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Essay on Global Warming

• Updated on  
• Apr 27, 2024

Being able to write an essay is an integral part of mastering any language. Essays form an integral part of many academic and scholastic exams like the SAT, and UPSC amongst many others. It is a crucial evaluative part of English proficiency tests as well like IELTS, TOEFL, etc. Major essays are meant to emphasize public issues of concern that can have significant consequences on the world. To understand the concept of Global Warming and its causes and effects, we must first examine the many factors that influence the planet’s temperature and what this implies for the world’s future. Here’s an unbiased look at the essay on Global Warming and other essential related topics.

Short Essay on Global Warming and Climate Change?

Since the industrial and scientific revolutions, Earth’s resources have been gradually depleted. Furthermore, the start of the world’s population’s exponential expansion is particularly hard on the environment. Simply put, as the population’s need for consumption grows, so does the use of natural resources , as well as the waste generated by that consumption.

Climate change has been one of the most significant long-term consequences of this. Climate change is more than just the rise or fall of global temperatures; it also affects rain cycles, wind patterns, cyclone frequencies, sea levels, and other factors. It has an impact on all major life groupings on the planet.

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What is Global Warming?

Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century, primarily due to the greenhouse gases released by people burning fossil fuels . The greenhouse gases consist of methane, nitrous oxide, ozone, carbon dioxide, water vapour, and chlorofluorocarbons. The weather prediction has been becoming more complex with every passing year, with seasons more indistinguishable, and the general temperatures hotter.

The number of hurricanes, cyclones, droughts, floods, etc., has risen steadily since the onset of the 21st century. The supervillain behind all these changes is Global Warming. The name is quite self-explanatory; it means the rise in the temperature of the Earth.

Also Read: What is a Natural Disaster?

What are the Causes of Global Warming?

According to recent studies, many scientists believe the following are the primary four causes of global warming:

• Deforestation 
• Greenhouse emissions
• Carbon emissions per capita

Extreme global warming is causing natural disasters , which can be seen all around us. One of the causes of global warming is the extreme release of greenhouse gases that become trapped on the earth’s surface, causing the temperature to rise. Similarly, volcanoes contribute to global warming by spewing excessive CO2 into the atmosphere.

The increase in population is one of the major causes of Global Warming. This increase in population also leads to increased air pollution . Automobiles emit a lot of CO2, which remains in the atmosphere. This increase in population is also causing deforestation, which contributes to global warming.

The earth’s surface emits energy into the atmosphere in the form of heat, keeping the balance with the incoming energy. Global warming depletes the ozone layer, bringing about the end of the world. There is a clear indication that increased global warming will result in the extinction of all life on Earth’s surface.

Also Read: Land, Soil, Water, Natural Vegetation, and Wildlife Resources

Solutions for Global Warming

Of course, industries and multinational conglomerates emit more carbon than the average citizen. Nonetheless, activism and community effort are the only viable ways to slow the worsening effects of global warming. Furthermore, at the state or government level, world leaders must develop concrete plans and step-by-step programmes to ensure that no further harm is done to the environment in general.

Although we are almost too late to slow the rate of global warming, finding the right solution is critical. Everyone, from individuals to governments, must work together to find a solution to Global Warming. Some of the factors to consider are pollution control, population growth, and the use of natural resources.

One very important contribution you can make is to reduce your use of plastic. Plastic is the primary cause of global warming, and recycling it takes years. Another factor to consider is deforestation, which will aid in the control of global warming. More tree planting should be encouraged to green the environment. Certain rules should also govern industrialization. Building industries in green zones that affect plants and species should be prohibited.

Also Read: Essay on Pollution

Effects of Global Warming

Global warming is a real problem that many people want to disprove to gain political advantage. However, as global citizens, we must ensure that only the truth is presented in the media.

This decade has seen a significant impact from global warming. The two most common phenomena observed are glacier retreat and arctic shrinkage. Glaciers are rapidly melting. These are clear manifestations of climate change.

Another significant effect of global warming is the rise in sea level. Flooding is occurring in low-lying areas as a result of sea-level rise. Many countries have experienced extreme weather conditions. Every year, we have unusually heavy rain, extreme heat and cold, wildfires, and other natural disasters.

Similarly, as global warming continues, marine life is being severely impacted. This is causing the extinction of marine species as well as other problems. Furthermore, changes are expected in coral reefs, which will face extinction in the coming years. These effects will intensify in the coming years, effectively halting species expansion. Furthermore, humans will eventually feel the negative effects of Global Warming.

Also Read: Concept of Sustainable Development

Sample Essays on Global Warming

Here are some sample essays on Global Warming:

Essay on Global Warming Paragraph in 100 – 150 words

Global Warming is caused by the increase of carbon dioxide levels in the earth’s atmosphere and is a result of human activities that have been causing harm to our environment for the past few centuries now. Global Warming is something that can’t be ignored and steps have to be taken to tackle the situation globally. The average temperature is constantly rising by 1.5 degrees Celsius over the last few years.

The best method to prevent future damage to the earth, cutting down more forests should be banned and Afforestation should be encouraged. Start by planting trees near your homes and offices, participate in events, and teach the importance of planting trees. It is impossible to undo the damage but it is possible to stop further harm.

Also Read: Social Forestry

Essay on Global Warming in 250 Words

Over a long period, it is observed that the temperature of the earth is increasing. This affected wildlife, animals, humans, and every living organism on earth. Glaciers have been melting, and many countries have started water shortages, flooding, and erosion and all this is because of global warming. 

No one can be blamed for global warming except for humans. Human activities such as gases released from power plants, transportation, and deforestation have increased gases such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere.                                              The main question is how can we control the current situation and build a better world for future generations. It starts with little steps by every individual. 

Start using cloth bags made from sustainable materials for all shopping purposes, instead of using high-watt lights use energy-efficient bulbs, switch off the electricity, don’t waste water, abolish deforestation and encourage planting more trees. Shift the use of energy from petroleum or other fossil fuels to wind and solar energy. Instead of throwing out the old clothes donate them to someone so that it is recycled. 

Donate old books, don’t waste paper.  Above all, spread awareness about global warming. Every little thing a person does towards saving the earth will contribute in big or small amounts. We must learn that 1% effort is better than no effort. Pledge to take care of Mother Nature and speak up about global warming.

Also Read: Types of Water Pollution

Essay on Global Warming in 500 Words

Global warming isn’t a prediction, it is happening! A person denying it or unaware of it is in the most simple terms complicit. Do we have another planet to live on? Unfortunately, we have been bestowed with this one planet only that can sustain life yet over the years we have turned a blind eye to the plight it is in. Global warming is not an abstract concept but a global phenomenon occurring ever so slowly even at this moment. Global Warming is a phenomenon that is occurring every minute resulting in a gradual increase in the Earth’s overall climate. Brought about by greenhouse gases that trap the solar radiation in the atmosphere, global warming can change the entire map of the earth, displacing areas, flooding many countries, and destroying multiple lifeforms. Extreme weather is a direct consequence of global warming but it is not an exhaustive consequence. There are virtually limitless effects of global warming which are all harmful to life on earth. The sea level is increasing by 0.12 inches per year worldwide. This is happening because of the melting of polar ice caps because of global warming. This has increased the frequency of floods in many lowland areas and has caused damage to coral reefs. The Arctic is one of the worst-hit areas affected by global warming. Air quality has been adversely affected and the acidity of the seawater has also increased causing severe damage to marine life forms. Severe natural disasters are brought about by global warming which has had dire effects on life and property. As long as mankind produces greenhouse gases, global warming will continue to accelerate. The consequences are felt at a much smaller scale which will increase to become drastic shortly. The power to save the day lies in the hands of humans, the need is to seize the day. Energy consumption should be reduced on an individual basis. Fuel-efficient cars and other electronics should be encouraged to reduce the wastage of energy sources. This will also improve air quality and reduce the concentration of greenhouse gases in the atmosphere. Global warming is an evil that can only be defeated when fought together. It is better late than never. If we all take steps today, we will have a much brighter future tomorrow. Global warming is the bane of our existence and various policies have come up worldwide to fight it but that is not enough. The actual difference is made when we work at an individual level to fight it. Understanding its import now is crucial before it becomes an irrevocable mistake. Exterminating global warming is of utmost importance and each one of us is as responsible for it as the next.  

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Essay on Global Warming UPSC

Always hear about global warming everywhere, but do we know what it is? The evil of the worst form, global warming is a phenomenon that can affect life more fatally. Global warming refers to the increase in the earth’s temperature as a result of various human activities. The planet is gradually getting hotter and threatening the existence of lifeforms on it. Despite being relentlessly studied and researched, global warming for the majority of the population remains an abstract concept of science. It is this concept that over the years has culminated in making global warming a stark reality and not a concept covered in books. Global warming is not caused by one sole reason that can be curbed. Multifarious factors cause global warming most of which are a part of an individual’s daily existence. Burning of fuels for cooking, in vehicles, and for other conventional uses, a large amount of greenhouse gases like carbon dioxide, and methane amongst many others is produced which accelerates global warming. Rampant deforestation also results in global warming as lesser green cover results in an increased presence of carbon dioxide in the atmosphere which is a greenhouse gas.  Finding a solution to global warming is of immediate importance. Global warming is a phenomenon that has to be fought unitedly. Planting more trees can be the first step that can be taken toward warding off the severe consequences of global warming. Increasing the green cover will result in regulating the carbon cycle. There should be a shift from using nonrenewable energy to renewable energy such as wind or solar energy which causes less pollution and thereby hinder the acceleration of global warming. Reducing energy needs at an individual level and not wasting energy in any form is the most important step to be taken against global warming. The warning bells are tolling to awaken us from the deep slumber of complacency we have slipped into. Humans can fight against nature and it is high time we acknowledged that. With all our scientific progress and technological inventions, fighting off the negative effects of global warming is implausible. We have to remember that we do not inherit the earth from our ancestors but borrow it from our future generations and the responsibility lies on our shoulders to bequeath them a healthy planet for life to exist. 

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Climate Change and Global Warming Essay

Global Warming and Climate Change are two sides of the same coin. Both are interrelated with each other and are two issues of major concern worldwide. Greenhouse gases released such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere cause Global Warming which leads to climate change. Black holes have started to form in the ozone layer that protects the earth from harmful ultraviolet rays. 

Human activities have created climate change and global warming. Industrial waste and fumes are the major contributors to global warming. 

Another factor affecting is the burning of fossil fuels, deforestation and also one of the reasons for climate change.  Global warming has resulted in shrinking mountain glaciers in Antarctica, Greenland, and the Arctic and causing climate change. Switching from the use of fossil fuels to energy sources like wind and solar. 

When buying any electronic appliance buy the best quality with energy savings stars. Don’t waste water and encourage rainwater harvesting in your community. 

Also Read: Essay on Air Pollution

Tips to Write an Essay

Writing an effective essay needs skills that few people possess and even fewer know how to implement. While writing an essay can be an assiduous task that can be unnerving at times, some key pointers can be inculcated to draft a successful essay. These involve focusing on the structure of the essay, planning it out well, and emphasizing crucial details.

Mentioned below are some pointers that can help you write better structure and more thoughtful essays that will get across to your readers:

• Prepare an outline for the essay to ensure continuity and relevance and no break in the structure of the essay
• Decide on a thesis statement that will form the basis of your essay. It will be the point of your essay and help readers understand your contention
• Follow the structure of an introduction, a detailed body followed by a conclusion so that the readers can comprehend the essay in a particular manner without any dissonance.
• Make your beginning catchy and include solutions in your conclusion to make the essay insightful and lucrative to read
• Reread before putting it out and add your flair to the essay to make it more personal and thereby unique and intriguing for readers  

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Ans. Both natural and man-made factors contribute to global warming. The natural one also contains methane gas, volcanic eruptions, and greenhouse gases. Deforestation, mining, livestock raising, burning fossil fuels, and other man-made causes are next.

Ans. The government and the general public can work together to stop global warming. Trees must be planted more often, and deforestation must be prohibited. Auto usage needs to be curbed, and recycling needs to be promoted.

Ans. Switching to renewable energy sources , adopting sustainable farming, transportation, and energy methods, and conserving water and other natural resources.

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Digvijay Singh

Having 2+ years of experience in educational content writing, withholding a Bachelor's in Physical Education and Sports Science and a strong interest in writing educational content for students enrolled in domestic and foreign study abroad programmes. I believe in offering a distinct viewpoint to the table, to help students deal with the complexities of both domestic and foreign educational systems. Through engaging storytelling and insightful analysis, I aim to inspire my readers to embark on their educational journeys, whether abroad or at home, and to make the most of every learning opportunity that comes their way.

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This was really a good essay on global warming… There has been used many unic words..and I really liked it!!!Seriously I had been looking for a essay about Global warming just like this…

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I want to learn how to write essay writing so I joined this page.This page is very useful for everyone.

Hi, we are glad that we could help you to write essays. We have a beginner’s guide to write essays ( https://leverageedu.com/blog/essay-writing/ ) and we think this might help you.

It is not good , to have global warming in our earth .So we all have to afforestation program on all the world.

thank you so much

Very educative , helpful and it is really going to strength my English knowledge to structure my essay in future

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Global warming is the increase in 𝓽𝓱𝓮 ᴀᴠᴇʀᴀɢᴇ ᴛᴇᴍᴘᴇʀᴀᴛᴜʀᴇs ᴏғ ᴇᴀʀᴛʜ🌎 ᴀᴛᴍᴏsᴘʜᴇʀᴇ

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Science News

Extreme weather in 2022 showed the global impact of climate change.

This year’s extremes were a glimpse of the future, if climate change continues unabated

A sign on the 110 freeway in Los Angeles warns drivers of extreme heat and urges energy conservation during a heat wave that baked the western United States in September.

Patrick T. Fallon/AFP/Getty Images

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By Carolyn Gramling

December 22, 2022 at 1:58 pm

It was another shattering year.

Climate change amped up weather extremes around the globe, smashing temperature records, sinking river levels to historic lows and raising rainfall to devastating highs. Droughts set the stage for wildfires and worsened food insecurity. Researchers found themselves pondering the limits of humans’ ability to tolerate extreme heat ( SN: 7/27/22 ).

The extreme events from 2022 pinpointed on the map below are just a sample of this year’s climate disasters. Each was exacerbated by human-caused climate change or is in line with projections of regional impacts.

In its Sixth Assessment Report, released in 2021 and 2022, the United Nations’ Intergovernmental Panel on Climate Change, or IPCC, warned that humans are dramatically overhauling Earth’s climate ( SN: 8/9/21 ). Earth’s average surface temperature has already risen by at least 1.1 degree Celsius  since preindustrial times, thanks to human inputs of heat-trapping gases to the atmosphere, particularly carbon dioxide and methane ( SN: 3/10/22 ). That warming has shifted the flow of energy around the planet, altering weather patterns, raising sea levels and  turning past extremes into new normals ( SN: 2/1/22 ).

And the world will have to weather more such climate extremes as carbon keeps accumulating in the atmosphere and global temperatures continue to rise. But IPCC scientists and others hope that, by highlighting the regional and local effects of climate change, the world will ramp up its efforts to reduce climate-warming emissions — averting a more disastrous future.

More Stories from Science News on Climate

The Arctic is warming rapidly. These clouds may hold clues as to why

Warm water is sneaking underneath the Thwaites Glacier — and rapidly melting it

‘The High Seas’ tells of the many ways humans are laying claim to the ocean

As the Arctic tundra warms, soil microbes likely will ramp up CO 2 production

A new approach to fighting wildfires combines local knowledge and AI

A ruinous hailstorm in Spain may have been supercharged by warming seas

Three reasons why the ocean’s record-breaking hot streak is devastating

Will stashing more CO 2 in the ocean help slow climate change?

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• State of the climate: How the world warmed in 2022

Zeke Hausfather

With a new year underway, most of the climate data for the whole of 2022 is now available. And this data shows that last year set new records for individual locations as well as the world as a whole. 

Here, Carbon Brief examines the latest data across the oceans, atmosphere, cryosphere and surface temperature of the planet (see the links below to navigate between sections). This 2022 review reveals:

• Ocean heat content: It was the warmest year on record for ocean heat content, which increased notably between 2021 and 2022.
• Surface temperature: It was between the fifth and sixth warmest year on record for surface temperature for the world as a whole, at between 1.1C and 1.3C above pre-industrial levels across different temperature datasets. The last eight years have been the eight warmest years since records began in the mid-1800s.
• A persistent triple-dip La Niña: The year ended up cooler than it would otherwise be due to persistent La Niña conditions in the tropical Pacific. Carbon Brief finds that 2022 would have been the second warmest year on record after 2020 in the absence of short-term variability from El Niño and La Niña events. 
• Warming over land: It was the warmest year on record in 28 countries – including China, France, Germany, Ireland, Italy, New Zealand, Portugal, Spain and the Uk – and in areas where 850 million people live.
• Extreme weather: 2022 saw extreme heatwaves over Europe, China, India, Pakistan and South America, as well as catastrophic flooding in Pakistan, Brazil, West Africa and South Africa. Climate change played a clear role in increasing the severity of all of these events.
• Comparison with climate model data: Observations for 2022 are close to the central estimate of climate models featured in the IPCC fifth assessment report.
• Warming of the atmosphere: It was the seventh or eighth warmest year in the lower troposphere – the lowest part of the atmosphere – depending on which dataset is used. The stratosphere – in the upper atmosphere – is cooling, due in part to heat trapped in the lower atmosphere by greenhouse gases.
• Sea level rise: Sea levels reached new record-highs, with notable acceleration over the past three decades.
• Greenhouse gases: Concentrations reached record levels for CO2, methane and nitrous oxide.
• Sea ice extent: Arctic sea ice saw its 10th lowest minimum extent on record, and was generally at the low end of the historical range for the year. Antarctic sea ice saw a new record low extent for much of 2022.
• Looking ahead to 2022: Carbon Brief predicts that global average surface temperatures in 2023 are most likely to be slightly warmer than 2022, but are unlikely to set a new all-time record given lingering La Niña conditions in the first half of the year.

Record ocean heat content

Last year was the warmest on record for the heat content of the world’s oceans. Ocean heat content (OHC) has increased by around 428 zettajoules – a billion trillion joules – since the 1940s. The heat increase in 2022 alone compared to 2021 – about 11 zettajoules – is around 19 times as much as the total energy produced by all human activities on Earth in 2020 (the latest year in which global primary energy statistics are available).

Human-emitted greenhouse gases trap extra heat in the atmosphere. While some of this warms the Earth’s surface, the vast majority – around of 93% – goes into the oceans. About two thirds of this accumulates in the top 700 metres, but some also ends up in the deep oceans. Annual OHC estimates between 1950 and present for both the upper 700 metres (light blue shading) and 700-2000 metre )dark blue) depths of the ocean are shown in the figure below.

In many ways, OHC represents a much better measure of climate change than global average surface temperatures. It is where most of the extra heat ends up and is much less variable on a year-to-year basis than surface temperatures.

Changes in the amount or rate of warming are much easier to detect in the OHC record than on the surface. For example, OHC shows little evidence of slowing down over the past eight years, despite a growing focus by climate sceptics on global surface temperature trends over that period. It also shows a distinct acceleration after 1991, matching the increased rate of greenhouse gas emissions over the past few decades.

Just about every year since 1991 has set a new OHC record, showing that heat has continued to accumulate in the Earth system as concentrations of atmospheric greenhouse gases have increased.

Fifth or sixth warmest year on the surface 

Global surface temperatures in 2022 were among the warmest measured since records began in the mid-1800s. Data from NASA , NOAA and the Met Office Hadley Centre/University of East Anglia’s (UEA) HadCRUT5 records show that 2022 was the sixth warmest year on record, while data from Berkeley Earth , Copern i cus ERA5 , JRA-55 , and AIRS satellite data show it as the fifth warmest. In most cases differences between these group’s rankings are small and within the range of measurement uncertainty.

The figure below shows global surface temperature records from the principal research groups around the world since 1970. These are created by combining ship- and buoy-based measurements of ocean sea surface temperatures with temperature readings of the surface air temperature from weather stations on land. Temperatures are shown as anomalies relative to a 1981-2010 average; note that the 1981-2010 period is around 0.6 to 0.8C warmer than the 1880-99 pre-industrial period across the different groups.

The global warming seen is not due to any adjustments made to the underlying temperature records. The figure above includes a “raw records” line (shown as a dotted line) calculated by Carbon Brief using data not subject to any adjustments or corrections for changes in measurement techniques. These adjustments only modestly affect the record after 1950. Before then, the adjusted temperature records actually show less warming than the raw data.

Global surface temperature records can be calculated back to 1850, though some groups choose to start their records in 1880 when more data was available. Prior to 1850, records exist for some specific regions, but are not sufficiently widespread to calculate global temperatures with high accuracy (though work is ongoing to identify and digitise additional records to extend these further back in time). These longer surface temperature records are created by combining ship- and buoy-based measurements of ocean sea surface temperatures with temperature readings of the surface air temperature from weather stations on land (Copernicus ERA5 and JRA-55 are an exception, as they use weather model-based reanalysis to combine lots of different data sources over time). 

The chart below shows global temperature records since 1850, with temperatures shown relative to the 1880-99 period to highlight warming since the pre-industrial period . 

Temperatures in 2022 were between 1.1C and 1.3C warmer than temperatures in the late 19th century (between 1880 and 1899), depending on the temperature record chosen. Last year represented between the eighth (NOAA and NASA) and 14th (Berkeley Earth) consecutive year that global temperatures have exceeded 1C above pre-industrial levels across the different datasets.

The past eight years of the record really stand out as much warmer than anything that has come before. This can be seen in the figure below from Berkeley Earth . Each shaded curve represents the annual average temperature for that year. The further that curve is to the right, the warmer it was.

The width of each year’s curve reflects the uncertainty in the annual temperature values (caused by factors such as changes in measurement techniques and the fact that some parts of the world have fewer measurement locations than others).

Second warmest year on record when La Niña is removed

Year-to-year variability in temperature records is mostly due to the influence of El Niño and La Niña events , which have a short-term warming or cooling impact on the climate. Other dips are associated with large volcanic eruptions . The longer-term warming of the climate is due to increases in atmospheric CO2 and other greenhouse gases emitted from human activity.

Last year’s temperatures were dragged down a bit by a moderately strong La Niña event during the year, which strengthened in the second half of 2022 of the year (creating a relatively rare “ triple dip ” La Niña event). Due to a lag of a few months between La Niña conditions in the Pacific and their peak effect on global temperatures, La Niña conditions – projected to persist into the first quarter of 2023 – will contribute to lower temperatures this year than would have otherwise occurred.

The figure below shows the El Niño (red shading) and La Niña (blue) conditions over the past 70 years (collectively referred to as the El Niño-Southern Oscillation, or “ENSO”). While not unprecedented, the extended La Niña conditions since the latter part of 2020 have extended for an unusually long period of time.

To assess the effects of El Niño and La Niña on the surface temperature record, Carbon Brief has produced an estimate of what temperatures would be in the absence of these events. The figure below shows the published Berkeley Earth temperature record compared to Carbon Brief’s estimate without El Niño or La Niña events.

Removing the effects of El Niño and La Niña from the temperature record would make 2022 the second warmest year on record. ( Dr Gavin Schmidt at NASA GISS finds a similar result ). It would also result in 2020 being the warmest year on record, rather than 2016, as 2016 temperatures were boosted by a large El Niño event. 

Removing ENSO effects also results in a clear warming trend over the past eight years, showing that the apparently flat temperatures over the period is largely the result of a strong El Niño (2015 and 2016) followed by a persistent La Niña (2021 and 2022).

Once El Niño effects are removed, the cooling impact of major volcanic eruptions – such as those in 1982 and 1991 – are also much easier to spot in the temperature record.

Rapid warming for the world’s land regions

The focus on global surface temperature as a key metric of climate change is important, but it can obscure very different rates of change across the planet.

For example, while most of the Earth’s surface is covered by oceans, nearly all human settlements and activities are in land areas. The land has been warming around 70% faster than the oceans – and 40% faster than the global average – in the years since 1970.

The figure below breaks down the Berkeley Earth temperature dataset into land-only (red) and ocean-only (blue) temperatures.

While the world as a whole has warmed by around 1.3C since the pre-industrial period (1850-1900) in the Berkeley Earth dataset, land areas have warmed a much larger amount – by 1.8C on average. In contrast, the oceans have warmed more slowly – by around 0.8C since pre-industrial times. (See Carbon Brief ’s guest post on why the land and ocean warm at different rates.)

Different parts of the land and ocean are also warming at different rates. The warmth in 2022 covered large regions of the world, with particularly anomalously high temperatures over Europe, China, the Middle East and parts of the Arctic, and relatively cool temperatures over the tropical Pacific due to La Niña conditions. The figure below, from Berkeley Earth, shows the average annual temperatures, relative to 1951-80, across the world for the year.

A year of climate extremes

In addition to being the fifth or sixth warmest year on record for the surface and setting a new record for ocean heat content, 2022 saw many climate extremes around the world. These include record-breaking extreme heat events in the UK and Europe , China, India and Pakistan and South America , and catastrophic flooding in Pakistan , Brazil , West Africa and South Africa . 

In all of these cases, scientists working with the World Weather Attribution team have found that these extremes were made worse by human-driven climate change. At the same time, researchers found more limited evidence of the role of climate change in worsening droughts in both Madagascar and the Sahel region of Africa.

In 2022, 28 countries saw their warmest year on record according to Berkeley Earth . This includes Afghanistan, Andorra, Belgium, Bosnia and Herzegovina, China, Croatia, Fiji, France, Germany, Ireland, Italy, Kyrgyzstan, Liechtenstein, Luxembourg, Malta, Monaco, Morocco, New Zealand, Papua New Guinea, Portugal, San Marino, Spain, Switzerland, the UK, Tajikistan, Tonga, Tunisia and Vanuatu.

Areas home to 850 million people saw their warmest year on record during 2022, while there was no location on Earth where annual average temperatures were among the coldest on record. The figure below, also from Berkeley Earth, shows the regions of the world where either warm (red shading) or cold (blue) records were set in 2022.

While most of western Europe and parts of north-west Africa saw their warmest year on record, Europe as a whole only recorded its second-warmest year, slightly below the record set in 2020. However, 2022 was still nearly 2.5C warmer than pre-industrial levels for the region, as shown in the figure below.

The July heatwave in the UK and Europe was particularly notable, shattering records in many countries. On 19 July, UK temperatures surpassed 40C for the first time on record , reaching 40.3C. This far exceeded the previous high of 38.7C set in 2019. The figure below shows the new record at the Coningsby Royal Air Force station in Lincolnshire, compared to all the prior hourly temperature measurements at that location since 1973, and demonstrates just how anomalously warm it was.

Researchers at World Weather Attribution found that the extreme heat in the UK was made at least 10 times more likely due to human-caused climate change experienced to-date.

Antarctica also experienced an exceptional climate event in early 2022. An atmospheric river on 18 March brought unusually warm air into Antarctica, and briefly pushed temperatures at the Vostok station 38.5C above the normal levels. This is likely the largest deviation above a climate normal ever recorded at a station, though there has not been any link established between this particular event and climate change.

Temperatures in-line with climate model projections

Climate models provide physics-based estimates of future warming given different assumptions about future emissions, greenhouse gas concentrations and other climate-influencing factors .

Here, Carbon Brief examines a collection of climate models – known as CMIP5 – used in the 2013 fifth assessment report (AR5) from the Intergovernmental Panel on Climate Change (IPCC). In CMIP5, model estimates of temperatures prior to 2005 are a “hindcast” using known past climate influences, while temperatures projected after 2005 are a “forecast” based on an estimate of how things might change. 

The figure below shows the range of individual CMIP5 models projections since 1950, as well as future projections through to 2100 under the middle-of-the-road RCP4.5 emissions scenario. The black line shows the average of 38 different models, while the grey area shows the 95% ( two standard deviation ) range of the model projections. Observational temperatures are plotted on top of the climate model data, with individual observational records represented by coloured lines.

Observations fall well within the range of CMIP5 climate model projections over the past 70 years. Temperatures in 2022 are slightly below the model average (as the average of all the models effectively averages out short-term variability from El Niño and La Niña events). 

The climate model outputs shown here are blended – that is, they combine surface air temperature over the land with sea surface temperatures over the ocean in the same way they are measured in the observational climate record. This allows for a more accurate comparison of the two. 

The latest generation of models –  CMIP6 – are not compared to observations in this state of the climate report. The most recent report from the IPCC’s sixth assessment report (AR6) has changed the way that the collection of models is used. Rather than simply taking the average of all the models (and their range) – as was the case in previous IPCC reports – the IPCC decided to use a weighted subset of models that agreed well with historical observations. This also reflected a narrowing of climate sensitivity in the most recent IPCC report – such that a number of new models fall outside the “very likely” sensitivity range. 

While the IPCC AR6 provided a new set of future “assessed warming” projections, these start in the year 2015, which makes comparisons with observations over such a short period not very informative.

Warming troposphere and cooling stratosphere

In addition to surface measurements over the world’s land and oceans, satellite microwave sounding units have been providing estimates of temperatures at various layers of the atmosphere since 1979. 

The lowest layer they estimate – the lower troposphere – reflects temperatures a few kilometres above the surface and shows a pattern of warming similar (though not identical) to surface temperature changes. The record produced by Remote Sensing Systems (RSS) shows 2022 as the eighth warmest year on record in the lower troposphere, while the record from the University of Alabama, Huntsville (UAH) shows it as the seventh warmest. The chart below shows the two records – RSS in red and UAH in blue – for the lower troposphere (TLT).

The lower troposphere tends to be influenced more strongly by El Niño and La Niña events than the surface. Therefore, satellite records show correspondingly larger warming or cooling spikes during these events. This is why, for example, 1998 shows up as one of the warmest years in satellites, but not in surface records.

The two lower-tropospheric temperature records show large differences after the early 2000s. RSS shows an overall rate of warming quite similar to surface temperature records, while UAH shows considerably slower warming in recent years than has been observed on the surface. Both have seen large adjustments in recent years that have warmed RSS and cooled UAH compared to prior versions of each record. 

Overall, there is more agreement with RSS to other records that include satellite data (such as reanalysis products like ERA5 and JRA-55 , as well as the shorter AIRS satellite-based surface temperature record), while the UAH record is a bit of an outlier compared to the others.

In addition to a temperature record of the lower troposphere, RSS and UAH also provide measurements of the lower stratosphere – a region of the upper atmosphere around 18km above the surface. The figure below shows lower stratospheric temperatures (TLS) records for both RSS (red) and UAH (blue) from 1979 through 2022.

The stratosphere has been cooling for the last few decades in a clear fingerprint of human greenhouse gases, which warm the lower part of the atmosphere by trapping heat while cooling the upper atmosphere as less heat escapes. If other factors – such as changing solar output – were causing climate change, both the stratosphere and troposphere would be warming. 

The lower stratosphere is affected by a number of factors in addition to greenhouse gases – including volcanic eruptions and ozone depletion. These play a smaller role in influencing the upper stratosphere, where the cooling trend due to greenhouse gases trapping heat in the lower parts of the atmosphere shows up even more clearly. This is illustrated in the chart below, which shows satellite temperature measurements at the top of the stratosphere (top line), in the upper stratosphere (middle) and lower stratosphere (bottom).

Accelerating sea level rise

Modern-day sea levels have risen to a new high, due to a combination of melting land ice (such as glaciers and ice sheets), the thermal expansion of water as it warms, and changes in land water storage . In recent years, there have been larger contributions to sea level rise from melting ice sheets and glaciers, as warmer temperatures accelerate ice sheet losses in Greenland and Antarctica .

Since the early 1990s, the increase in global sea level has been estimated using altimeter data from satellites. Earlier global sea levels have been reconstructed from a network of global tide gauge measurements. This allows researchers to estimate how sea level has changed since the late 1800s . 

The chart below shows five different modern sea level rise datasets (coloured lines), along with satellite altimeter measurements from NASA satellites as assessed by the University of Colorado (in black) after 1993. (As sea level rise data has not yet been released for the whole year, the 2022 value is estimated based on data through October.)

Sea levels have risen by around 0.2 metres (200mm) since 1900. While sea level rise estimates mostly agree in recent decades, larger divergences are evident before 1980. There is also evidence of accelerating sea level rise over the post-1993 period when high-quality satellite altimetry data is available. (See Carbon Brief’s explainer on how climate change is accelerating sea level rise.)

A portion of this sea level rise is being driven by melting land glaciers. Scientists measure the mass of glaciers around the world using a variety of remote-sensing techniques, as well as through GRACE measurements of the Earth’s gravitational field. The balance between snow falling on a glacier and ice loss through melting and the breaking off – or “ calving ” – of icebergs determines if glaciers grow or shrink over time.

An international consortium called the World Glacier Monitoring Service tracks 164 different glaciers in 19 different regions around the world. The figure below shows the change in global average glacier mass from 1950 through to the end of 2021 (2022 values are not yet available). Note that glacier melt is reported in metres of water equivalent , which is a measure of how much mass has been lost on average.

Greenland ice sheets have become a larger contributor to sea level rise in recent years due to accelerating loss of mass. The year 2022 was the 26th in a row where Greenland lost ice overall, with 84Gt of ice lost over the 12 months from September 2021 to August 2022. Greenland last saw an annual net gain of ice in 1996.

The figure below, from a study published in late 2021, shows the cumulative mass balance change – that is, the net ice loss – from Greenland between 1970 and October 2021. The different coloured lines indicate estimates from different studies. The authors find that Greenland has lost around 6 trillion metric tons of ice over that period, or more than 700 tons lost per person for every person on the planet.

Atmospheric greenhouse gases concentrations reach new highs

Greenhouse gas concentrations reached a new high in 2022, driven by human emissions from fossil fuels, land use and agriculture.

Three greenhouse gases – CO2, methane (CH4) and nitrous oxide (N2O) – are responsible for the bulk of additional heat trapped by human activities. CO2 is by far the largest factor, accounting for roughly 42% of the increase in global surface temperatures since the pre-industrial era (1850-1900).

Methane accounts for 28%, while nitrous oxide accounts for around 5%. The remaining 25% comes from other factors including carbon monoxide, black carbon and halocarbons , such as CFCs.

Human emissions of greenhouse gases have increased atmospheric concentrations of CO2, methane and nitrous oxide to their highest levels in at least a few million years – if not longer. 

The figure below shows concentrations of these greenhouse gases – in parts per million (ppm) for CO2 (blue line) and parts per billion (ppb) for methane (orange) and nitrous oxide (red) – from the early 1980s through to October 2022 for CO2 and September 2022 for CH4 and N2O (the most recent data currently available).

Methane concentrations in particular have seen a sharp rise over the past decade after a plateau in the 2000s. This appears to be driven by both increased emissions from agriculture and fossil fuels, in roughly equal measure. 

Arctic and Antarctic sea ice

Arctic sea ice was at the low end of the historical (1979-2010) range for most of 2022, but did not set any new all-time low records. The summer minimum extent – the lowest recorded level for the year – was the joint-10th smallest since records began in the late 1970s.

Antarctic sea ice, on the other hand, saw new record low levels for much of the year, including February through April, June through August, late October and December. Unlike the Arctic, the long-term trend in sea ice extent in Antarctica is less clear . There is an active debate in the community about the relative role of climate change versus natural variability in the record lows experienced over the past two years, though it is clear that warming is driving at least some of the recent decline. 

The figure below shows both Arctic (red line) and Antarctic (blue line) sea ice extent for each day of the year, along with how it compares to the historical range (corresponding shading).

Looking forward to 2023 and beyond

With a “triple dip” La Niña event in the latter part of 2022, La Niña conditions are expected to persist for at least the first three months of 2023. Because there is a lag of a few months between when El Niño or La Niña conditions peak in the tropical Pacific and their impact on global temperatures, these La Niña conditions will likely have a lingering cooling influence on 2023 temperatures. 

Here, Carbon Brief provides its own prediction of likely 2023 temperatures using the NASA GISTEMP dataset – and based on a model using the year, temperatures over past three months, and projections of El Niño/La Niña conditions over the next six months. The figure below shows the Carbon Brief prediction in yellow, along with its 95% confidence interval (black bars) and the historical NASA GISTEMP record (grey dots).

While the uncertainties are still wide at this point, we find that 2023 is very likely to be between the third and ninth warmest year on record, with a best estimate of being the fifth warmest on record – similar to 2022. If an El Niño event develops in late 2023, however, it will make it likely that 2024 will set a new record.

There have been three other published predictions – from the UK Met Office , NASA’s Dr Gavin Schmidt and Berkeley Earth – of what temperatures might look like in 2023. The figure below shows the four different 2023 predictions compared to the NASA GISTEMP temperature record. These have been “normalised” to show 2023 warming relative to the 2001-20 period in the NASA dataset. This is to remove any differences in predictions due to divergences between datasets in earlier parts of the temperature record.

While the Met Office, Berkeley Earth and Carbon Brief estimates all have 2023 as similar (albeit a tad warmer) to 2022, with a relatively small chance of setting a new record, Dr Schmidt predicts that 2023 has a real chance of tying with 2016 and 2020 as the warmest year on record. It is worth noting that the Berkeley Earth projection ended up being the most accurate last year in predicting 2022 temperatures.

However, what matters for the climate is not the leaderboard of individual years. Rather, it is the long-term upward trend in global temperatures driven by human emissions of greenhouse gases . Until the world reduces emissions down to net-zero, the planet will continue to warm . 

It is almost certain that the next time the world sees a moderate to strong El Niño event, that year will set a new all-time temperature record. 

Similarly, as the chart below highlights, if the warming trend over the past 40 years continues, average surface temperatures are likely to pass 1.5C in the mid-2030s and 2C by around 2060.

DeBriefed 14 June 2024: Bonn climate talks; When Earth could breach 1.5C; How polluter taxes could raise climate funds

分析：月度碳排放量下降或表明中国已在2023年碳达峰

DeBriefed 7 June 2024: Sheinbaum and Modi elected; Hottest May; Factchecking net-zero costs

Guest post: Tracking the unprecedented impact of humans on the climate

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The IPCC Climate Change 2022 Impacts Report: Why it matters

Large-scale reduction in carbon dioxide pollution key to climate change response, scientists say.

This week some 270 top scientists from 67 countries, including two NOAA scientists, are completing the final details of a large-scale report: Climate Change 2022: Impacts, Adaptation & Vulnerability, the second part of the Sixth Assessment Report offsite link . The report will describe how climate change is already affecting the world’s human and natural systems.

View of the Chukchi Borderlands where the Arctic, Pacific and Atlantic ocean basins meet. (Image credit: Caitlin Bailey/Global Foundation for Ocean Exploration)

Additional Resources

United Nations Intergovernmental Panel on Climate Change offsite link

NOAA’s Climate.gov

NOAA’s Ocean Acidification Program

NOAA’s Alaska Fisheries Science Center

On Monday, February 28, the United Nations Intergovernmental Panel on Climate Change offsite link (IPCC) will release its latest report, which will focus on climate solutions and regional and local adaptation. It will also assess the feasibility of various adaptation strategies to curb current and predicted impacts of climate change.

The IPCC was established 34 years ago to provide actionable information on climate change for decision makers. IPCC reports are the result of a unique collaboration of scientific expertise and political consensus. The new report will reaffirm that the science pertaining to climate change is settled, and the most important response to climate change is large-scale reduction in carbon dioxide pollution that drives global warming.

...we have to act, we need a whole of society approach, no one can be left out, no household, no businesses, no government... Debra Roberts , Co-chair of the IPCC Working Group II report

To learn more about why this new report matters and what went into creating it, NOAA interviewed NOAA authors, Libby Jewett, director of the NOAA’s Ocean Acidification Program, and Kirstin Holsman, a research scientist from NOAA’s Alaska Fisheries Science Center. They served on an international team of authors who assessed scientific literature to prepare the new IPCC report’s chapter on North America.

The authors underwent a rigorous selection process offsite link , and have spent three years working with fellow scientists to provide the best available science on climate change impacts, vulnerabilities and adaptation in North America. Holsman is also an author of the report’s cross-chapter paper on Polar Regions.

Watch: The below video interview features NOAA scientists Libby Jewett and Kirstin Holsman  — contributors to the latest IPCC report.

In a recent briefing on the new report, Debra Roberts, co-chair of the IPCC Working Group II report and head of Sustainable and Resilient City Initiatives in eThekwini Municipality in Durban, South Africa, said the report will tell a story about how today’s civilization has been built on ways of life that have accelerated the decline of nature to the detriment of humans and ecosystems. The report’s authors will lay out a clear case for a major turnaround that will better integrate the world’s economic and environmental systems for a sustainable future.

Hans-Otto Pörtner, co-chair of the IPCC report and an expert on climate impacts on natural systems, said the report would call out the major barriers to creating a sustainable future in the face of rising temperatures and accelerating climate change impacts on every sector and every person on Earth.

“We have an education gap and an implementation gap,” Pörtner said. “The traffic rules to move toward more sustainable lives are not reaching people.” 

Added Roberts: “There is a strong message across all the IPCC reports that we have to act, we need a whole of society approach, no one can be left out, no household, no businesses, no government, and it's that whole of society scale that we haven’t put in place that is urgently needed.”

Media contact

Monica Allen,  monica.allen@noaa.gov , (202) 379-6693

Related Features //

A problem built into our relationship with energy itself. Photo by Ferdinando Scianna/Magnum

Deep warming

Even if we ‘solve’ global warming, we face an older, slower problem. waste heat could radically alter earth’s future.

by Mark Buchanan   + BIO

The world will be transformed. By 2050, we will be driving electric cars and flying in aircraft running on synthetic fuels produced through solar and wind energy. New energy-efficient technologies, most likely harnessing artificial intelligence, will dominate nearly all human activities from farming to heavy industry. The fossil fuel industry will be in the final stages of a terminal decline. Nuclear fusion and other new energy sources may have become widespread. Perhaps our planet will even be orbited by massive solar arrays capturing cosmic energy from sunlight and generating seemingly endless energy for all our needs.

That is one possible future for humanity. It’s an optimistic view of how radical changes to energy production might help us slow or avoid the worst outcomes of global warming. In a report from 1965, scientists from the US government warned that our ongoing use of fossil fuels would cause global warming with potentially disastrous consequences for Earth’s climate. The report, one of the first government-produced documents to predict a major crisis caused by humanity’s large-scale activities, noted that the likely consequences would include higher global temperatures, the melting of the ice caps and rising sea levels. ‘Through his worldwide industrial civilisation,’ the report concluded, ‘Man is unwittingly conducting a vast geophysical experiment’ – an experiment with a highly uncertain outcome, but clear and important risks for life on Earth.

Since then, we’ve dithered and doubted and argued about what to do, but still have not managed to take serious action to reduce greenhouse gas emissions, which continue to rise. Governments around the planet have promised to phase out emissions in the coming decades and transition to ‘green energy’. But global temperatures may be rising faster than we expected: some climate scientists worry that rapid rises could create new problems and positive feedback loops that may accelerate climate destabilisation and make parts of the world uninhabitable long before a hoped-for transition is possible.

Despite this bleak vision of the future, there are reasons for optimists to hope due to progress on cleaner sources of renewable energy, especially solar power. Around 2010, solar energy generation accounted for less than 1 per cent of the electricity generated by humanity. But experts believe that, by 2027, due to falling costs, better technology and exponential growth in new installations, solar power will become the largest global energy source for producing electricity. If progress on renewables continues, we might find a way to resolve the warming problem linked to greenhouse gas emissions. By 2050, large-scale societal and ecological changes might have helped us avoid the worst consequences of our extensive use of fossil fuels.

It’s a momentous challenge. And it won’t be easy. But this story of transformation only hints at the true depth of the future problems humanity will confront in managing our energy use and its influence over our climate.

As scientists are gradually learning, even if we solve the immediate warming problem linked to the greenhouse effect, there’s another warming problem steadily growing beneath it. Let’s call it the ‘deep warming’ problem. This deeper problem also raises Earth’s surface temperature but, unlike global warming, it has nothing to do with greenhouse gases and our use of fossil fuels. It stems directly from our use of energy in all forms and our tendency to use more energy over time – a problem created by the inevitable waste heat that is generated whenever we use energy to do something. Yes, the world may well be transformed by 2050. Carbon dioxide levels may stabilise or fall thanks to advanced AI-assisted technologies that run on energy harvested from the sun and wind. And the fossil fuel industry may be taking its last breaths. But we will still face a deeper problem. That’s because ‘deep warming’ is not created by the release of greenhouse gases into the atmosphere. It’s a problem built into our relationship with energy itself.

F inding new ways to harness more energy has been a constant theme of human development. The evolution of humanity – from early modes of hunter-gathering to farming and industry – has involved large systematic increases in our per-capita energy use. The British historian and archaeologist Ian Morris estimates, in his book Foragers, Farmers, and Fossil Fuels: How Human Values Evolve (2015), that early human hunter-gatherers, living more than 10,000 years ago, ‘captured’ around 5,000 kcal per person per day by consuming food, burning fuel, making clothing, building shelter, or through other activities. Later, after we turned to farming and enlisted the energies of domesticated animals, we were able to harness as much as 30,000 kcal per day. In the late 17th century , the exploitation of coal and steam power marked another leap: by 1970, the use of fossil fuels allowed humans to consume some 230,000 kcal per person per day. (When we think about humanity writ large as ‘humans’, it’s important to acknowledge that the average person in the wealthiest nations consumes up to 100 times more energy than the average person in the poorest nations.) As the global population has risen and people have invented new energy-dependent technologies, our global energy use has continued to climb.

In many respects, this is great. We can now do more with less effort and achieve things that were unimaginable to the 17th-century inventors of steam engines, let alone to our hominin ancestors. We’ve made powerful mining machines, superfast trains, lasers for use in telecommunications and brain-imaging equipment. But these creations, while helping us, are also subtly heating the planet.

All the energy we humans use – to heat our homes, run our factories, propel our automobiles and aircraft, or to run our electronics – eventually ends up as heat in the environment. In the shorter term, most of the energy we use flows directly into the environment. It gets there through hot exhaust gases, friction between tires and roads, the noises generated by powerful engines, which spread out, dissipate, and eventually end up as heat. However, a small portion of the energy we use gets stored in physical changes, such as in new steel, plastic or concrete. It’s stored in our cities and technologies. In the longer term, as these materials break down, the energy stored inside also finds its way into the environment as heat. This is a direct consequence of the well-tested principles of thermodynamics.

Waste heat will pose a problem that is every bit as serious as global warming from greenhouse gases

In the early decades of the 21st century , this heat created by simply using energy, known as ‘waste heat’, is not so serious. It’s equivalent to roughly 2 per cent of the planetary heating imbalance caused by greenhouse gases – for now. But, with the passing of time, the problem is likely to get much more serious. That’s because humans have a historical tendency to consistently discover and produce things, creating entirely new technologies and industries in the process: domesticated animals for farming; railways and automobiles; global air travel and shipping; personal computers, the internet and mobile phones. The result of such activities is that we end up using more and more energy, despite improved energy efficiency in nearly every area of technology.

During the past two centuries at least (and likely for much longer), our yearly energy use has doubled roughly every 30 to 50 years . Our energy use seems to be growing exponentially, a trend that shows every sign of continuing. We keep finding new things to do and almost everything we invent requires more and more energy: consider the enormous energy demands of cryptocurrency mining or the accelerating energy requirements of AI.

If this historical trend continues, scientists estimate waste heat will pose a problem in roughly 150-200 years that is every bit as serious as the current problem of global warming from greenhouse gases. However, deep heating will be more pernicious as we won’t be able to avoid it by merely shifting from one kind energy to another. A profound problem will loom before us: can we set strict limits on all the energy we use? Can we reign in the seemingly inexorable expansion of our activities to avoid destroying our own environment?

Deep warming is a problem hiding beneath global warming, but one that will become prominent if and when we manage to solve the more pressing issue of greenhouse gases. It remains just out of sight, which might explain why scientists only became concerned about the ‘waste heat’ problem around 15 years ago.

O ne of the first people to describe the problem is the Harvard astrophysicist Eric Chaisson, who discussed the issue of waste heat in a paper titled ‘Long-Term Global Heating from Energy Usage’ (2008). He concluded that our technological society may be facing a fundamental limit to growth due to ‘unavoidable global heating … dictated solely by the second law of thermodynamics, a biogeophysical effect often ignored when estimating future planetary warming scenarios’. When I emailed Chaisson to learn more, he told me the history of his thinking on the problem:

It was on a night flight, Paris-Boston [circa] 2006, after a UNESCO meeting on the environment when it dawned on me that the IPCC were overlooking something. While others on the plane slept, I crunched some numbers literally on the back of an envelope … and then hoped I was wrong, that is, hoped that I was incorrect in thinking that the very act of using energy heats the air, however slightly now.

The transformation of energy into heat is among the most ubiquitous processes of physics

Chaisson drafted the idea up as a paper and sent it to an academic journal. Two anonymous reviewers were eager for it to be published. ‘A third tried his damnedest to kill it,’ Chaisson said, the reviewer claiming the findings were ‘irrelevant and distracting’. After it was finally published, the paper got some traction when it was covered by a journalist and ran as a feature story on the front page of The Boston Globe . The numbers Chaisson crunched, predictions of our mounting waste heat, were even run on a supercomputer at the US National Center for Atmospheric Research, by Mark Flanner, a professor of earth system science. Flanner, Chaisson suspected at the time, was likely ‘out to prove it wrong’. But, ‘after his machine crunched for many hours’, he saw the same results that Chaisson had written on the back of an envelope that night in the plane.

Around the same time, also in 2008, two engineers, Nick Cowern and Chihak Ahn, wrote a research paper entirely independent of Chaisson’s work, but with similar conclusions. This was how I first came across the problem. Cowern and Ahn’s study estimated the total amount of waste heat we’re currently releasing to the environment, and found that it is, right now, quite small. But, like Chaisson, they acknowledged that the problem would eventually become serious unless steps were taken to avoid it.

That’s some of the early history of thinking in this area. But these two papers, and a few other analyses since, point to the same unsettling conclusion: what I am calling ‘deep warming’ will be a big problem for humanity at some point in the not-too-distant future. The precise date is far from certain. It might be 150 years , or 400, or 800, but it’s in the relatively near future, not the distant future of, say, thousands or millions of years. This is our future.

T he transformation of energy into heat is among the most ubiquitous processes of physics. As cars drive down roads, trains roar along railways, planes cross the skies and industrial plants turn raw materials into refined products, energy gets turned into heat, which is the scientific word for energy stored in the disorganised motions of molecules at the microscopic level. As a plane flies from Paris to Boston, it burns fuel and thrusts hot gases into the air, generates lots of sound and stirs up contrails. These swirls of air give rise to swirls on smaller scales which in turn make smaller ones until the energy ultimately ends up lost in heat – the air is a little warmer than before, the molecules making it up moving about a little more vigorously. A similar process takes place when energy is used by the tiny electrical currents inside the microchips of computers, silently carrying out computations. Energy used always ends up as heat. Decades ago, research by the IBM physicist Rolf Landauer showed that a computation involving even a single computing bit will release a certain minimum amount of heat to the environment.

How this happens is described by the laws of thermodynamics, which were described in the mid-19th century by scientists including Sadi Carnot in France and Rudolf Clausius in Germany. Two key ‘laws’ summarise its main principles.

The first law of thermodynamics simply states that the total quantity of energy never changes but is conserved. Energy, in other words, never disappears, but only changes form. The energy initially stored in an aircraft’s fuel, for example, can be changed into the energetic motion of the plane. Turn on an electric heater, and energy initially held in electric currents gets turned into heat, which spreads into the air, walls and fabric of your house. The total energy remains the same, but it markedly changes form.

We’re generating waste heat all the time with everything we do

The second law of thermodynamics, equally important, is more subtle and states that, in natural processes, the transformation of energy always moves from more organised and useful forms to less organised and less useful forms. For an aircraft, the energy initially concentrated in jet fuel ends up dissipated in stirred-up winds, sounds and heat spread over vast areas of the atmosphere in a largely invisible way. It’s the same with the electric heater: the organised useful energy in the electric currents gets dissipated and spread into the low-grade warmth of the walls, then leaks into the outside air. Although the amount of energy remains the same, it gradually turns into less organised, less usable forms. The end point of the energy process produces waste heat. And we’re generating it all the time with everything we do.

Data on world energy consumption shows that, collectively, all humans on Earth are currently using about 170,000 terawatt-hours (TWh), which is a lot of energy in absolute terms – a terawatt-hour is the total energy consumed in one hour by any process using energy at a rate of 1 trillion watts. This huge number isn’t surprising, as it represents all the energy being used every day by the billions of cars and homes around the world, as well as by industry, farming, construction, air traffic and so on. But, in the early 21st century , the warming from this energy is still much less than the planetary heating due to greenhouse gases.

Concentrations of greenhouse gases such as CO 2 and methane are quite small, and only make a fractional difference to how much of the Sun’s energy gets trapped in the atmosphere, rather than making it back out to space. Even so, this fractional difference has a huge effect because the stream of energy arriving from the Sun to Earth is so large. Current estimates of this greenhouse energy imbalance come to around 0.87 W per square meter, which translates into a total energy figure about 50 times larger than our waste heat. That’s reassuring. But as Cowern and Ahn wrote in their 2008 paper, things aren’t likely to stay this way over time because our energy usage keeps rising. Unless, that is, we can find some radical way to break the trend of using ever more energy.

O ne common objection to the idea of the deep warming is to claim that the problem won’t really arise. ‘Don’t worry,’ someone might say, ‘with efficient technology, we’re going to find ways to stop using more energy; though we’ll end up doing more things in the future, we’ll use less energy.’ This may sound plausible at first, because we are indeed getting more efficient at using energy in most areas of technology. Our cars, appliances and laptops are all doing more with less energy. If efficiency keeps improving, perhaps we can learn to run these things with almost no energy at all? Not likely, because there are limits to energy efficiency.

Over the past few decades, the efficiency of heating in homes – including oil and gas furnaces, and boilers used to heat water – has increased from less than 50 per cent to well above 90 per cent of what is theoretically possible. That’s good news, but there’s not much more efficiency to be realised in basic heating. The efficiency of lighting has also vastly improved, with modern LED lighting turning something like 70 per cent of the applied electrical energy into light. We will gain some efficiencies as older lighting gets completely replaced by LEDs, but there’s not a lot of room left for future efficiency improvements. Similar efficiency limits arise in the growing or cooking of food; in the manufacturing of cars, bikes and electronic devices; in transportation, as we’re taken from place to place; in the running of search engines, translation software, GPT-4 or other large-language models.

Even if we made significant improvements in the efficiencies of these technologies, we will only have bought a little time. These changes won’t delay by much the date when deep warming becomes a problem we must reckon with.

Optimising efficiencies is just a temporary reprieve, not a radical change in our human future

As a thought experiment, suppose we could immediately improve the energy efficiency of everything we do by a factor of 10 – a fantastically optimistic proposal. That is, imagine the energy output of humans on Earth has been reduced 10 times , from 170,000 TWh to 17,000 TWh . If our energy use keeps expanding, doubling every 30-50 years or so (as it has for centuries), then a 10-fold increase in waste heat will happen in just over three doubling times, which is about 130 years : 17,000 TWh doubles to 34,000 TWh , which doubles to 68,000 TWh , which doubles to 136,000 TWh , and so on. All those improvements in energy efficiency would quickly evaporate. The date when deep warming hits would recede by 130 years or so, but not much more. Optimising efficiencies is just a temporary reprieve, not a radical change in our human future.

Improvements in energy efficiency can also have an inverse effect on our overall energy use. It’s easy to think that if we make a technology more efficient, we’ll then use less energy through the technology. But economists are deeply aware of a paradoxical effect known as ‘rebound’, whereby improved energy efficiency, by making the use of a technology cheaper, actually leads to more widespread use of that technology – and more energy use too. The classic example, as noted by the British economist William Stanley Jevons in his book The Coal Question (1865), is the invention of the steam engine. This new technology could extract energy from burning coal more efficiently, but it also made possible so many new applications that the use of coal increased. A recent study by economists suggests that, across the economy, such rebound effects might easily swallow at least 50 per cent of any efficiency gains in energy use. Something similar has already happened with LED lights, for which people have found thousands of new uses.

If gains in efficiency won’t buy us lots of time, how about other factors, such as a reduction of the global population? Scientists generally believe that the current human population of more than 8 billion people is well beyond the limits of our finite planet, especially if a large fraction of this population aspires to the resource-intensive lifestyles of wealthy nations. Some estimates suggest that a more sustainable population might be more like 2 billion , which could reduce energy use significantly, potentially by a factor of three or four. However, this isn’t a real solution: again, as with the example of improved energy efficiency, a one-time reduction of our energy consumption by a factor of three will quickly be swallowed up by an inexorable rise in energy use. If Earth’s population were suddenly reduced to 2 billion – about a quarter of the current population – our energy gains would initially be enormous. But those gains would be erased in two doubling times, or roughly 60-100 years , as our energy demands would grow fourfold.

S o, why aren’t more people talking about this? The deep warming problem is starting to get more attention. It was recently mentioned on Twitter by the German climate scientist Stefan Rahmstorf, who cautioned that nuclear fusion, despite excitement over recent advances, won’t arrive in time to save us from our waste heat, and might make the problem worse. By providing another cheap source of energy, fusion energy could accelerate both the growth of our energy use and the reckoning of deep warming. A student of Rahmstorf’s, Peter Steiglechner, wrote his master’s thesis on the problem in 2018. Recognition of deep warming and its long-term implications for humanity is spreading. But what can we do about the problem?

Avoiding or delaying deep warming will involve slowing the rise of our waste heat, which means restricting the amount of energy we use and also choosing energy sources that exacerbate the problem as little as possible. Unlike the energy from fossil fuels or nuclear power, which add to our waste energy burden, renewable energy sources intercept energy that is already on its way to Earth, rather than producing additional waste heat. In this sense, the deep warming problem is another reason to pursue renewable energy sources such as solar or wind rather than alternatives such as nuclear fusion, fission or even geothermal power. If we derive energy from any of these sources, we’re unleashing new flows of energy into the Earth system without making a compensating reduction. As a result, all such sources will add to the waste heat problem. However, if renewable sources of energy are deployed correctly, they need not add to our deposition of waste heat in the environment. By using this energy, we produce no more waste heat than would have been created by sunlight in the first place.

Take the example of wind energy. Sunlight first stirs winds into motion by heating parts of the planet unequally, causing vast cells of convection. As wind churns through the atmosphere, blows through trees and over mountains and waves, most of its energy gets turned into heat, ending up in the microscopic motions of molecules. If we harvest some of this wind energy through turbines, it will also be turned into heat in the form of stored energy. But, crucially, no more heat is generated than if there had been no turbines to capture the wind.

The same can hold true for solar energy. In an array of solar cells, if each cell only collects the sunlight falling on it – which would ordinarily have been absorbed by Earth’s surface – then the cells don’t alter how much waste heat gets produced as they generate energy. The light that would have warmed Earth’s surface instead goes into the solar cells, gets used by people for some purpose, and then later ends up as heat. In this way we reduce the amount of heat being absorbed by Earth by precisely the same amount as the energy we are extracting for human use. We are not adding to overall planetary heating. This keeps the waste energy burden unchanged, at least in the relatively near future, even if we go on extracting and using ever larger amounts of energy.

Covering deserts in dark panels would absorb a lot more energy than the desert floor

Chaisson summarised the problem quite clearly in 2008:

I’m now of the opinion … that any energy that’s dug up on Earth – including all fossil fuels of course, but also nuclear and ground-sourced geothermal – will inevitably produce waste heat as a byproduct of humankind’s use of energy. The only exception to that is energy arriving from beyond Earth, this is energy here and now and not dug up, namely the many solar energies (plural) caused by the Sun’s rays landing here daily … The need to avoid waste heat is indeed the single, strongest, scientific argument to embrace solar energies of all types.

But not just any method of gathering solar energy will avoid the deep warming problem. Doing so requires careful engineering. For example, covering deserts with solar panels would add to planetary heating because deserts reflect a lot of incident light back out to space, so it is never absorbed by Earth (and therefore doesn’t produce waste heat). Covering deserts in dark panels would absorb a lot more energy than the desert floor and would heat the planet further.

We’ll also face serious problems in the long run if our energy appetite keeps increasing. Futurists dream of technologies deployed in space where huge panels would absorb sunlight that would otherwise have passed by Earth and never entered our atmosphere. Ultimately, they believe, this energy could be beamed down to Earth. Like nuclear energy, such technologies would add an additional energy source to the planet without any compensating removal of heating from the sunlight currently striking our planet’s surface. Any effort to produce more energy than is normally available from sunlight at Earth’s surface will only make our heating problems worse.

D eep warming is simply a consequence of the laws of physics and our inquisitive nature. It seems to be in our nature to constantly learn and develop new things, changing our environment in the process. For thousands of years, we have harvested and exploited ever greater quantities of energy in this pursuit, and we appear poised to continue along this path with the rapidly expanding use of renewable energy sources – and perhaps even more novel sources such as nuclear fusion. But this path cannot proceed indefinitely without consequences.

The logic that more energy equals more warming sets up a profound dilemma for our future. The laws of physics and the habits ingrained in us from our long evolutionary history are steering us toward trouble. We may have a technological fix for greenhouse gas warming – just shift from fossil fuels to cleaner energy sources – but there is no technical trick to get us out of the deep warming problem. That won’t stop some scientists from trying.

Perhaps, believing that humanity is incapable of reducing its energy usage, we’ll adopt a fantastic scheme to cool the planet, such as planetary-scale refrigeration or using artificially engineered tornadoes to transport heat from Earth’s surface to the upper atmosphere where it can be radiated away to space. As far-fetched as such approaches sound, scientists have given some serious thought to these and other equally bizarre ideas, which seem wholly in the realm of science fiction. They’re schemes that will likely make the problem worse not better.

We will need to transform the human story. It must become a story of doing less, not more

I see several possibilities for how we might ultimately respond. As with greenhouse gas warming, there will probably be an initial period of disbelief, denial and inaction, as we continue with unconstrained technological advance and growing energy use. Our planet will continue warming. Sooner or later, however, such warming will lead to serious disruptions of the Earth environment and its ecosystems. We won’t be able to ignore this for long, and it may provide a natural counterbalance to our energy use, as our technical and social capacity to generate and use ever more energy will be eroded. We may eventually come to some uncomfortable balance in which we just scrabble out a life on a hot, compromised planet because we lack the moral and organisational ability to restrict our energy use enough to maintain a sound environment.

An alternative would require a radical break with our past: using less energy. Finding a way to use less energy would represent a truly fundamental rupture with all of human history, something entirely novel. A rupture of this magnitude won’t come easily. However, if we could learn to view restrictions on our energy use as a non-negotiable element of life on Earth, we may still be able to do many of the things that make us essentially human: learning, discovering, inventing, creating. In this scenario, any helpful new technology that comes into use and begins using lots of energy would require a balancing reduction in energy use elsewhere. In such a way, we might go on with the future being perpetually new, and possibly better.

None of this is easily achieved and will likely mirror our current struggles to come to agreements on greenhouse gas heating. There will be vicious squabbles, arguments and profound polarisation, quite possibly major wars. Humanity will never have faced a challenge of this magnitude, and we won’t face up to it quickly or easily, I expect. But we must. Planetary heating is in our future – the very near future and further out as well. Many people will find this conclusion surprisingly hard to swallow, perhaps because it implies fundamental restrictions on our future here on Earth: we can’t go on forever using more and more energy, and, at the same time, expecting the planet’s climate to remain stable.

The world will likely be transformed by 2050. And, sometime after that, we will need to transform the human story. The narrative arc of humanity must become a tale of continuing innovation and learning, but also one of careful management. It must become a story, in energy terms, of doing less, not more. There’s no technology for entirely escaping waste heat, only techniques.

This is important to remember as we face up to the extremely urgent challenge of heating linked to fossil-fuel use and greenhouse gases. Global warming is just the beginning of our problems. It’s a testing ground to see if we can manage an intelligent and coordinated response. If we can handle this challenge, we might be better prepared, more capable and resilient as a species to tackle an even harder one.

The disruption nexus

Moments of crisis, such as our own, are great opportunities for historic change, but only under highly specific conditions

Roman Krznaric

History of science

His radiant formula

Stephen Hawking’s greatest legacy – a simple little equation now 50 years old – revealed a shocking aspect of black holes

Roger Highfield

What is intelligent life?

Our human minds hold us back from truly understanding the many brilliant ways that other creatures solve their problems

Abigail Desmond & Michael Haslam

Pleasure and pain

Eulogy for silence

Tinnitus is like a constant scream inside my head, depriving me of what I formerly treasured: the moments of serene quiet

Diego Ramírez Martín del Campo

History of ideas

Chaos and cause

Can a butterfly’s wings trigger a distant hurricane? The answer depends on the perspective you take: physics or human agency

Erik Van Aken

Philosophy of mind

Do plants have minds?

In the 1840s, the iconoclastic scientist Gustav Fechner made an inspired case for taking seriously the interior lives of plants

Rachael Petersen

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Why 2022 will matter for climate action

As the world picks up speed in its race against climate change and moves forward from the 2021 Glasgow Climate Change Conference, let’s look at ten key global events in 2022 that will shape critical conversations and influence public policy decisions around one of the most defining issues of our time.  

(TBD) | 5th UN Conference on Least Developed Countries (LDC5) | Doha, Qatar

There are 46 countries , spanning from Afghanistan to Zambia, that are considered Least Developed Countries (LDCs). They are home to about 13 percent of the world’s population and 40 percent of its poorest people. They are highly vulnerable to countless shocks - from economic, public health to climate change. They remain at the forefront of the climate crisis and are disproportionately affected by extreme weather events. And unfortunately, they lack critical financing to support climate-resilient measures and infrastructure.  

LDC5 , a conference that happens every 10 years - will include a high-level thematic roundtable on climate change to discuss the unique and urgent issues that LDCs face and the necessary support that they need to ensure that much-needed economic growth does not take place at the expense of their already fragile ecosystems and diminishing natural resources.  

February - September | IPCC  Assessment Report | Global

The Intergovernmental Panel on Climate Change (IPCC), which publishes assessments of climate science every six to seven years, will launch its first comprehensive assessment report since the adoption of the Paris Agreement in 2015. 

The IPCC’s Sixth Assessment Report (AR6) will encompass contributions from three working groups led by some of the world’s leading scientists on the physical understanding of the climate system and climate change [Working Group I - published in August 2021]; the impacts of climate change [Working Group II]; and the progress on mitigation and efforts to limit emissions [Working Group III].   

End of February | Working Group II Report | Impacts, Adaptation and Vulnerability  

This report will cover the impacts of climate change on human and natural systems, observing their vulnerabilities, ability and limitations to adapt to climate change. It will look at options for creating a sustainable future through an equitable and integrated approach to mitigation and adaptation efforts at all scales.   

Early April | Working Group III Report | Mitigation of Climate Change

This report will focus on global and national efforts to mitigate the devastating and varying impacts of climate change, looking at innovation and solutions in energy and urban systems, and in sectors such as agriculture, forestry and land use, buildings, transport and industry. It will look at the link between short to medium and long-term plans to curb emissions, highlighting the importance of governments’ national action plans, the nationally determined contributions (NDCs) under the Paris Agreement.   

September | Synthesis Report | Climate Change 2022

Finally, the Synthesis report , which will integrate contributions from the three Working Groups as well as from the Special Reports produced within the cycle - Global Warming of 1.5C ; Climate Change and Land ; and the Ocean and Cryosphere in a Changing Climate - will be launched ahead of COP27.

2 - 6 May  | XV World Forestry Congress 2022 | Seoul, Republic of Korea

Eliminating emissions from deforestation and promoting forest regrowth and landscape restoration could reduce global net emissions by up to 30 percent. Over the next decade, forests could provide as much as 50 percent of the cost-effective mitigation available. 

Taking place under the theme, Building a Green, Healthy and Resilient Future with Forests, the World Forestry Congress will focus on six sub-themes, including reversing forest loss, sustainable use of nature-based solutions and forest resources, and forest monitoring and data collection.    

9 - 21 May | 15th UN Conference on Desertification | Côte d'Ivoire

The Intergovernmental Panel on Climate Change warned in 2019 that roughly 500 million people live in areas that experience desertification. When land is degraded, it becomes less productive, restricting what can be grown and reducing the soil’s ability to absorb carbon. This exacerbates climate change and extreme weather events such as drought, heatwaves and dust storms, while climate change in turn exacerbates land degradation in many different ways.

The next Conference on Desertification will be an urgent call to scale up land restoration as well as nature-based solutions for climate action.    

2 - 3 June | Stockholm+50 | Sweden

Fifty years ago, the first world conference on the environment played a significant role in drawing attention to the inextricable goals of poverty alleviation and environmental protection - a link that has influenced climate debates ever since, recognizing the interconnections between humans and nature. 

Consequently, the conference gave birth to environmental diplomacy - in an effort to reconcile economic development and environmental management, paving the way for the establishment of the UN Environment Programme (UNEP) and the concept of sustainable development. It also resulted in the formation of national environmental ministries and a series of new global agreements to protect the environment.  

Today, as UNEP marks five decades of its work to strengthen environmental diplomacy, standards and practices, it will host Stockholm+50 with Sweden and Kenya, aiming to recommit and strengthen our ability to overcome the triple planetary crisis of climate change, nature and biodiversity loss, and pollution and waste.  

26 - 30 June | World Urban Forum 11 | Katowice, Poland

Cities across the globe are facing – and fighting – climate change . Home to 4.5 billion people today, cities are projected to grow by almost 50 percent by 2050. They are engines of growth and innovation, generating 80 percent of the world’s GDP along with 70 percent of global carbon emissions. In recent years, as the epicentre of growth, cities have been struggling to respond to the COVID-19 pandemic and to prepare for the worsening impact of climate change.

By 2050, 800 million people in 570 coastal cities could see sea-level rise of half a meter and intensifying storm surges. Global warming may leave more than 1.6 billion urbanites facing an average summertime temperature of 35C. Despite the growing challenges, cities have also been on the frontline of the climate movement and more recently, more than 1,000 cities announced their intention to reach net-zero greenhouse gas emissions by 2050.

Organized under the theme, Transforming our Cities for a Better Urban Future , the forthcoming World Urban Forum will be an opportunity to look at the future of cities based on existing trends, challenges and opportunities as well as how they can be better prepared to handle present and future shocks.   

Sacred plant helps forge a climate-friendly future in Paraguay

El Niño and climate crisis raise drought fears in Madagascar

The El Niño climate pattern, a naturally occurring phenomenon, can significantly disrupt global weather systems, but the human-made climate emergency is exacerbating the destructive effects.

“Verified for Climate” champions: Communicating science and solutions

Gustavo Figueirôa, biologist and communications director at SOS Pantanal, and Habiba Abdulrahman, eco-fashion educator, introduce themselves as champions for “Verified for Climate,” a joint initiative of the United Nations and Purpose to stand up to climate disinformation and put an end to the narratives of denialism, doomism, and delay.

Facts and figures

• What is climate change?
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Cutting emissions

• Explaining net zero
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News | January 12, 2023

Nasa says 2022 fifth warmest year on record, warming trend continues.

Lee esta nota de prensa en español here .

Earth's average surface temperature in 2022 effectively tied with 2015 as the fifth warmest on record, according to an analysis by NASA. Continuing the planet's long-term warming trend, global temperatures in 2022 were 1.6 degrees Fahrenheit (0.89 degrees Celsius) above the average for NASA's baseline period (1951-1980), scientists from NASA's Goddard Institute for Space Studies (GISS) in New York reported.

“This warming trend is alarming,” said NASA Administrator Bill Nelson. “Our warming climate is already making a mark: Forest fires are intensifying; hurricanes are getting stronger; droughts are wreaking havoc and sea levels are rising. NASA is deepening our commitment to do our part in addressing climate change. Our Earth System Observatory will provide state-of-the-art data to support our climate modeling, analysis and predictions to help humanity confront our planet’s changing climate.”

The past nine years have been the warmest years since modern recordkeeping began in 1880. This means Earth in 2022 was about 2 degrees Fahrenheit (or about 1.11 degrees Celsius) warmer than the late 19th century average.

“The reason for the warming trend is that human activities continue to pump enormous amounts of greenhouse gases into the atmosphere, and the long-term planetary impacts will also continue,” said Gavin Schmidt, director of GISS, NASA's leading center for climate modeling.

Human-driven greenhouse gas emissions have rebounded following a short-lived dip in 2020 due to the COVID-19 pandemic. Recently, NASA scientists, as well as international scientists, determined carbon dioxide emissions were the highest on record in 2022. NASA also identified some super-emitters of methane – another powerful greenhouse gas – using the Earth Surface Mineral Dust Source Investigation instrument that launched to the International Space Station last year.

The Arctic region continues to experience the strongest warming trends – close to four times the global average – according to GISS research presented at the 2022 annual meeting of the American Geophysical Union, as well as a separate study .

Communities around the world are experiencing impacts scientists see as connected to the warming atmosphere and ocean. Climate change has intensified rainfall and tropical storms, deepened the severity of droughts, and increased the impact of storm surges. Last year brought torrential monsoon rains that devastated Pakistan and a persistent megadrought in the U.S. Southwest. In September, Hurricane Ian became one of the strongest and costliest hurricanes to strike the continental U.S.

Tracking Our Changing Planet

NASA’s global temperature analysis is drawn from data collected by weather stations and Antarctic research stations, as well as instruments mounted on ships and ocean buoys. NASA scientists analyze these measurements to account for uncertainties in the data and to maintain consistent methods for calculating global average surface temperature differences for every year. These ground-based measurements of surface temperature are consistent with satellite data collected since 2002 by the Atmospheric Infrared Sounder on NASA's Aqua satellite and with other estimates.

NASA uses the period from 1951-1980 as a baseline to understand how global temperatures change over time. That baseline includes climate patterns such as La Niña and El Niño, as well as unusually hot or cold years due to other factors, ensuring it encompasses natural variations in Earth's temperature.

Many factors can affect the average temperature in any given year. For example, 2022 was one of the warmest on record despite a third consecutive year of La Niña conditions in the tropical Pacific Ocean. NASA scientists estimate that La Niña’s cooling influence may have lowered global temperatures slightly (about 0.11 degrees Fahrenheit or 0.06 degrees Celsius) from what the average would have been under more typical ocean conditions.

A separate, independent analysis by the National Oceanic and Atmospheric Administration (NOAA) concluded that the global surface temperature for 2022 was the sixth highest since 1880. NOAA scientists use much of the same raw temperature data in their analysis and have a different baseline period (1901-2000) and methodology. Although rankings for specific years can differ slightly between the records, they are in broad agreement and both reflect ongoing long-term warming.

NASA's full dataset of global surface temperatures through 2022, as well as full details with code of how NASA scientists conducted the analysis, are publicly available from GISS.

GISS is a NASA laboratory managed by the Earth Sciences Division of the agency's Goddard Space Flight Center in Greenbelt, Maryland. The laboratory is affiliated with Columbia University's Earth Institute and School of Engineering and Applied Science in New York.

For more information about NASA's Earth science programs, visit:

https://www.nasa.gov/earth

News Media Contacts

Tylar Greene Headquarters, Washington 202-358-0030 [email protected]

Jacob Richmond Goddard Space Flight Center, Greenbelt, Md. 301-286-0535 [email protected]

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Climate Change 2022: Impacts, Adaptation and Vulnerability

The working group ii contribution to the ipcc sixth assessment report assesses the impacts of climate change, looking at ecosystems, biodiversity, and human communities at global and regional levels. it also reviews vulnerabilities and the capacities and limits of the natural world and human societies to adapt to climate change., summary for policymakers.

The Summary for Policymakers (SPM) provides a high-level summary of the key findings of the Working Group II Report and is approved by the IPCC member governments line by line.

Technical Summary

The Technical Summary (TS) provides extended summary of key findings and serves as a link between the comprehensive assessment of the Working Group II Report and the concise SPM.

Full Report

The 18 Chapters and 7 Cross-Chapter Papers of the Working Group II Report assess the impacts of climate change on nature and humanity, and their capacities and limits for adaptation.

Frequently Asked Questions

The collection of Frequently Asked Questions (FAQs) contains all of the report’s FAQs as well as overarching FAQs, which were produced as a special outreach material

Fact Sheets

The regional and crosscutting factsheets give a snapshot of the key findings, distilled from the relevant Chapters and Cross-Chapter Papers, the TS and the Global to Regional Atlas.

Global to Regional Atlas

The Global to Regional Atlas provides visual summaries and case studies on climate change impacts and risks, vulnerabilities and adaptation, building on the report key findings.

Point of departure and key concepts

Chapter 1 introduces the Working Group II contribution to AR6, explains its framing and context, and elaborates on the key concepts used in the report.

Terrestrial and freshwater ecosystems and their services

Chapter 2 provides a global assessment of climate change impacts and risks to terrestrial and freshwater ecosystems and their services as well as adaptation options to reduce risks.

Ocean and coastal ecosystems and their services

Chapter 3 provides a global assessment of climate change impacts and risks to ocean and coastal ecosystems and their services as well as adaptation options to reduce risks.

Chapter 4 assesses current climate change impacts on the global water cycle, projected water-related risks for human and natural systems, and adaptation options and effectiveness.

Food, fibre, and other ecosystem products

Chapter 5 provides a global assessment of climate change impacts and risks to agriculture, forestry, fisheries and aquaculture, as well as adaptation solutions and limits.

Cities, settlements and key infrastructure

Chapter 6 assesses climate change impacts and risks to cities, human settlements and key infrastructure as well as enabling conditions and options for adaptation.

Health, wellbeing and the changing structure of communities

Chapter 7 provides a global assessment of current climate change impacts and projected risks to health and wellbeing, as well as adaptations solutions and limits.

Poverty, livelihoods and sustainable development

Chapter 8 assesses climate change impacts and future risks to the most vulnerable and marginalized people and livelihoods as well as enabling conditions and options for adaptation.

Chapter 9 assesses climate change impacts and risks, vulnerability as well as enabling conditions, barriers and options for adaptation and climate resilient development in Africa.

Chapter 10 assesses climate change impacts and risks, vulnerability as well as enabling conditions, barriers and options for adaptation and climate resilient development in Asia.

Australasia

Chapter 11 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in Australia and New Zealand.

Central and South America

Chapter 12 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in Central and South America.

Chapter 13 assesses climate change impacts and risks, vulnerability as well as enabling conditions, barriers and options for adaptation and climate resilient development in Europe.

North America

Chapter 14 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in North America.

Small Islands

Chapter 15 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in Small Islands.

Key risks across sectors and regions

Chapter 16 synthesizes observed climate change impacts, adaptation-related responses, limits to adaptation and the key risks identified across sectors and regions.

Decision-making options for managing risk

Chapter 17 assesses the options, processes and enabling conditions for climate risk management as well as the governance and applicability of adaptation options in various contexts.

Climate resilient development pathways

Chapter 18 assesses the ways climate impacts and risks hinder Climate Resilient Development (CRD) in different sectoral and regional contexts as well as the ways of achieving CRD.

Cross-Chapter Papers

Cross-Chapter Paper 1

Biodiversity hotspots (land, coasts and oceans).

CCP1 assesses the impacts and vulnerability to climate change of terrestrial, freshwater and marine ecosystems considered to be biodiversity hotspots.

Cross-Chapter Paper 2

Cities and settlements by the sea.

CCP2 assesses climate change impacts and risks to coastal cities and settlements, their vulnerability as well as enabling conditions and options for adaptation.

Cross-Chapter Paper 3

Deserts, semi-arid areas, and desertification.

CCP3 assesses climate change impacts and risks to deserts and semi-arid areas, including desertification, as well as options for adaptation and climate resilient development.

Cross-Chapter Paper 4

Mediterranean region.

CCP4 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in the Mediterranean region.

Cross-Chapter Paper 5

CCP5 assesses climate change impacts and risks, vulnerability as well as barriers and options for adaptation and climate resilient development in mountain regions.

Cross-Chapter Paper 6

Polar regions.

CCP6 assesses the climate change impacts and risks to ecosystems and human systems in Polar Regions, as well as options for adaptation and climate resilient development.

Cross-Chapter Paper 7

Tropical forests.

CCP7 assesses climate change impacts and risks, as well as barriers and options for adaptation and increasing climate resilience in tropical forests.

Contributors

Expert reviewers.

Global Temperature Report for 2022

Berkeley Earth, a California-based non-profit research organization, has been preparing independent analyses of global mean temperature changes since 2013. The following is our report on global mean temperature during 2022.

We conclude that 2022 was nominally the fifth warmest year on Earth since 1850. Our estimate of the global mean temperature in 2022 was slightly warmer than 2021 and similar to 2015. Given the uncertainties associated with temperature measurements, 2022 and 2015 are essentially tied, making 2022 consistent with either the fifth or sixth warmest year. .

The last eight years have included all eight of the warmest years observed in the instrumental record.

Year-to-year rankings are likely to reflect short-term natural variability. In 2021 and 2022, a persistent La Niña event has reduced temperatures somewhat compared to years without a La Niña event. Overall, the long-term trend remains consistent with an ongoing pattern of global warming. The cyclic warming and cooling due to El Niño and La Niña are one of the largest sources of year-to-year internal variability in the global average temperature, often adding or subtracting 0.1 °C from the global average. It is fairly likely that once El Niño related warming returns, that we will also see a new record warm year.

While not a record warm year overall, 8.5% of the Earth’s surface did have a record warm annual average locally in 2022. By chance, these areas coincided with a number of major population centers, including in Western Europe. We estimate that 850 million people experienced a record warm annual average in 2022. None of the Earth’s surface had a record cold annual average in 2022.

In addition, 2022 was notable for:

• New national record high annual averages for 28 countries, including the UK, Spain, France, Germany, New Zealand, and China
• Record warmth in Western Europe, including the first ever 40 °C day in the United Kingdom
• Ongoing long-lived La Nina event, providing a extended period of slightly reduced temperatures
• March heatwave in Antarctica that produced the highest temperature excursion above normal ever measured anywhere on Earth
• Droughts affecting Europe, China, and US Southwest. Floods in Pakistan.
• Nominally the 7 th warmest year on land and the 6 th warmest year in the oceans.

Annual Temperature Anomaly

The global mean temperature in 2022 is estimated to have been 1.24 °C (2.24 °F) above the average temperature from 1850-1900, a period often used as a pre-industrial baseline for global temperature targets. This is ~0.03 °C (~0.05 °F) warmer than in 2021. As a result, 2021 is nominally the fifth warmest year to have been directly observed, though the years 2015, 2017, 2018, 2021, and 2022 all cluster closely together relative to their uncertainty estimates. In particular 2022 and 2015 are essentially tied, and 2022 could just as easily be regarded as the 6 th warmest year.

This global mean temperature in 2022 is equivalent to 0.91 °C (1.64 °F) above the 1951-1980 average, which is often used as a reference period for comparing global climate analyses.

The last eight years stand out as the eight warmest years to have been directly observed.

The temperature uncertainties can be visualized using the schematic below where each year’s temperature estimate is represented by a distribution reflecting its uncertainty. In the analysis that Berkeley Earth conducts, the uncertainty on the mean temperature is approximately 0.03 °C (0.05 °F) for recent years. The global mean temperature in 2022 fell squarely between those observed in 2015 & 2017. These three years have substantially overlapping uncertainties, leading to an associated uncertainty in the true relative rankings of these years.

The last eight years have been part of a period of significant warmth well above all previous years since 1850. This reflects the long-term trend towards global warming. Though 2022 is cooler than some of the other recent years, its overall temperature remains consistent with the long-term warming trend.

Land Average Temperature in 2022

On land, 2022 was nominally the seventh warmest year observed, and is effectively tied with 2021 and 2015.

In 2022, the land average temperature was 1.70 ± 0.04 °C above the average temperature from 1850 to 1900. As discussed below, though it was only the fifth warmest year globally, some territories saw record warm annual averages in 2022.

Temperature Distribution in 2022

The following map shows how local temperatures in 2022 have increased relative to the average temperature in 1951-1980. Prominent warmth over Europe and Asia is visible this year, as is La Niña associated cooling in the Pacific.

As can be expected from the global warming caused by greenhouse gases, the temperature increase over the globe is broadly distributed, affecting nearly all land and ocean areas. In 2022, 88% of the Earth’s surface was significantly warmer than the average temperature during 1951-1980, 7% was of a similar temperature, and only 5% was significantly colder.

We estimate that 8.5% of the Earth’s surface set a new local record for the warmest annual average. As discussed below, these locations with record warm annual averages are home to ~850 million people.

In 2022, no places on Earth experienced a record cold annual average.

Land areas generally show more than twice as much warming as the ocean. When compared to the 1850-1900 averages, the land average in 2022 has increased 1.70 ± 0.04 °C (3.07 ± 0.07 °F) and the ocean surface temperature, excluding sea ice regions, has increased 0.86 ± 0.04 °C (1.55 ± 0.06 °F).

2022 is nominally the 7 th warmest year on land, though the difference between 5 th , 6 th , and 7 th is negligible. For the ocean surface, we find that 2022 nominally ranks as the 6 th warmest year. However, the differences between the 5 th , 6 th , 7 th and 8 th warmest years in the ocean are all small compared to the measurement uncertainty. The following figure shows land and ocean temperature changes relative to the average from 1850 to 1900. The tendency for land averages to increase more quickly than ocean averages is clearly visible.

As in other recent years, 2022 also shows strong warming over the Arctic that exceeds the Earth’s mean rate of warming. Over the last 40 years, the Arctic has warmed at ~4 times the average global rate. This is consistent with the process known as Arctic amplification. By melting sea ice and decreasing snow cover, warming in the Arctic allows more sunlight to be absorbed, which in turn leads to additional warming. However, 2022 was not as warm as other recent years, and is ranked only 10 th overall, slightly ahead of 2021, but significantly cooler than 2020 or 2016. Similarly, Arctic sea ice melt in 2022 was less extreme than other recent years, though still well ahead on what was typical 30 years ago.

Both the tendency for land to warm faster than ocean and the higher rate of warming over the Arctic are expected based on our understanding of how increases in greenhouse gas concentrations will impact the Earth’s climate. As has been reported by the Global Carbon Project and other observers, 2022 saw a new record for the level of carbon dioxide in the atmosphere . This is due to the continued accumulation of carbon dioxide from human activities. The annual amount of carbon dioxide emitted in 2022 was 1.0% higher than 2021 and set a new all-time high. The previous record high for carbon dioxide emissions occurred in 2019 before a brief decline due to the COVID-19 pandemic.

Development of La Niña

The emergence of the La Niña weather phenomenon in the latter half of 2020 had a substantial influence on temperatures at the end of 2020, and an even larger impact on 2021 and 2022.

La Niña is characterized by the emergence of a large area of relatively cool water in the eastern equatorial Pacific, as can be clearly seen in the annual average map above. In addition to the immediate cooling in the Pacific, La Niña can have far-reaching effects on global circulation and weather patterns. This disruption of weather patterns tends to be associated with an extended period of somewhat reduced global average temperatures that can last for months beyond the peak of the La Niña in the Pacific.

Notably, the monthly time series of ocean average temperatures shifted sharply lower at the end of 2020 due to La Niña, and has remained below the highs seen in 2016 and 2020. These somewhat reduced ocean temperatures helped to keep the global average temperature in 2022 lower than in other recent years.

Ocean temperatures in the equatorial Pacific have maintained their La Niña conditions throughout 2022. The current La Niña began in 2020 and is expected to continue into early 2023, making it relatively long-lived. During La Niña conditions, the Eastern Equatorial Pacific Ocean is characterized by below normal temperatures, and increased downward transport of surface heat. As a result, global mean temperatures tend to be somewhat lower during La Niña years. During El Niño years, the opposite is present, as warm water in the Eastern Pacific releases extra heat into the atmosphere.

Roughly speaking, we expect each 1 °C (2 °F) temperature shift in the main El Niño / La Niña region to drive a corresponding ~0.1 °C (~0.2 °F) variation in the global mean temperature, with a lag of 3-6 months. In other words, we expect the effect of La Niña in 2022 was roughly to make the annual average ~0.1 °C (~0.2 °F) colder than it might otherwise have been.

When the variability in the Pacific inevitably shifts back towards an El Niño — as appears likely in mid-to-late 2023 — the additional 0.1-0.2 °C (0.2-0.4 °F) of warmth expected to be released by El Niño will greatly increase the odds that the following year will be a new record for global average temperature (i.e. a possible 2024 record, if El Niño does return in mid/late 2023).

National Average Temperature

Though the focus of our work is on global and regional climate analysis, it is also possible to use our data to estimate national temperature trends.

In Berkeley Earth’s estimation, 2022 had the warmest annual average since instrumental records began in the following 28 countries:

Afghanistan, Andorra, Belgium, Bosnia and Herzegovina, China, Croatia, Fiji, France, Germany, Ireland, Italy, Kyrgyzstan, Liechtenstein, Luxembourg, Malta, Monaco, Morocco, New Zealand, Papua New Guinea, Portugal, San Marino, Spain, Switzerland, United Kingdom, Tajikistan, Tonga, Tunisia, and Vanuatu

This is similar to 25 countries that set national average records in 2021 and significantly fewer than the 45 countries that experienced record warming in 2020. However, it still represents a substantial fraction of the world’s population that has just lived through the warmest year in their local history. Looking at the specific sub-national locations where record annual averages occurred, we estimate that approximately 850 million people live in places that observed their locally warmest year during 2022.

The following chart provides a summary of the warming that countries experienced in 2022 relative their 1951 to 1980 averages.

These estimates for the changes in national annual average temperatures are derived from our global temperature fields. Due to uncertainties in the analysis and the limits of our spatial resolution some national average estimates may differ slightly from the values reported by their respective national weather agencies.

During 2023, Berkeley Earth will be launching an updated high resolution analysis which will improve our ability to characterize such local, regional, and national changes, and reduce uncertainties associated with topography and small-scale weather variability.

Temperatures in Europe

Western Europe was particularly noteworthy for extraordinary warmth in 2022, with many countries setting new national records, including, Spain, France, Germany, Italy, and the United Kingdom.

Governments in Europe attributed more than 26,000 deaths to summer heat waves, though this may be an underestimate as 53,000 excess deaths were reported in July alone. The summer heat waves included the first ever 40 °C (104 °F) day in the UK , a milestone that would be virtually impossible without global warming and was also met with an outbreak of wildfires.

The associated summer drought was one of the worst in Europe during the last 500 years . Warm weather in Europe continued all the way into winter, and has resulted in unusually low levels of snow in the Alps .

Considered as a whole, the European continent experienced it’s second warmest year on record in 2022.

Weather station chart showing the July heat wave that ultimately pushed multiple UK weather stations above 40 °C for the first time since observations have begun, greatly exceeding previous measurements at this site and setting a new all-time record in the process.

Antarctic Heatwave

One of the most remarkable weather events in 2022 was the March heatwave impacting Antarctica .

An intrusion of an atmospheric river into the Antarctic plateau briefly pushed local temperatures at the manned Vostok station +38.5 °C (+69.3 °F) above normal for this time of year.

This is the largest temperature excursion above normal ever measured at any weather station anywhere on Earth.

Monthly Temperature Patterns

Every month in 2022 was at least 1.0 °C (1.8 °F) warmer than the 1850 to 1900 average. However, the first several months of the year were relatively cool compared to other recent years, partly due to the effects of La Niña. June was the only month in 2022 that set a record high average for the month. The relatively coldest month was November which ranked 13 th in 2022.

Long-term Trend

Though it is interesting to understand the characteristics of individual years, global warming is ultimately about the long-term evolution of Earth’s climate. The following chart shows a ten-year moving average of the Earth’s surface temperature, plotted relative to the average temperature from 1850-1900.

Since 1980, the overall trend is +0.19 °C/decade (+0.34 °F/decade) and has changed little during this period. By continuing this trend, we can make a rough guess of how the near-future climate may develop if the forces driving global warming continue to progress at their present rate.

As shown in the chart, several recent years have had temperatures more than 1.2 °C (2.2 °F) above the average temperature from 1850-1900, often used as an estimate of the pre-industrial climate. The Paris Agreement on Climate Change aims to keep global temperature rise to well below 2 °C (3.6 °F) and encourages parties to strive for warming of no more than 1.5 °C (2.7 °F). At the current rate of progression, the increase in Earth’s long-term average temperature will reach 1.5 °C (2.7 °F) above the 1850-1900 average by around 2034 and 2 °C (3.6 °F) will be reached around 2060. The increasing abundance of greenhouse gases in the atmosphere due to human activities is the direct cause of this recent global warming. If the Paris Agreement’s goal of no more than 2 °C (3.6 °F) warming is to be reached, significant progress towards reducing greenhouse gas emissions needs to be made soon.

Global Mean Temperature Prediction for 2023

Based on historical variability and current conditions, it is possible to roughly estimate what global mean temperature might be expected in 2023. Our current estimate is that 2023 is likely to be similar to 2022 or slightly warmer. With the current continuation of La Niña conditions, it is likely that 2023 remains relatively cool. The swings from El Niño to La Niña and back again are the largest source of interannual variability in the global temperature record, with La Niña associated with cooler conditions. However, there remains a modest chance (14%) that 2023 could end up as a new warmest year if the El Niño / La Niña system swings back to warmth early in 2023.

It is nearly certain (>99% likelihood) that 2023 will remain within the top-ten warmest years; however, there is a ~50% chance that 2023 will rank no higher than the 5 th warmest year.

Though 2023 is expected to be somewhat cool, that does not mean that global warming has stopped. Like 2022, the central estimate for 2023 remains close to the long-term trend. Minor year-to-year fluctuations are entirely natural and may provide the world with a year of slightly less exceptional weather, but over the long-term temperatures are expected to continue along a warming trend as long as humans continue to add additional greenhouse gases to the atmosphere.

A potential shift towards El Niño in mid-to-late 2023 would likely push 2024 towards record warmth.

Comparisons with Other Groups

When preparing our year-end reports, Berkeley Earth traditionally compares our global mean temperature analysis to the results of four other groups that also report global mean surface temperature. The following chart compares Berkeley Earth’s analysis of global mean temperature to that of the NASA’s GISTEMP , NOAA’s GlobalTemp , the UK’s HadCRUT , and  ECMWF ‘s reanalysis. All of these groups produce a similar understanding of recent climate change. As of the time this document was being finalized, 2022 values for HadCRUT were not available.

While Berkeley Earth and ECMWF view 2022 as nominally the 5 th warmest year, NASA and NOAA place 2022 as nominally the 6 th warmest year. Given the tiny margin of difference between the 5 th and 6 th warmest years, we don’t consider these differences between analysis groups to be significant.

Slight disagreements in the ranking are common and reflect both the uncertainty in these estimations and the differences in how various research programs look at the Earth. Each uses a somewhat different selection of source data and different methods of interpolation and correcting for measurement errors. Some methods are more limited than others. For example, NOAA omits most of the polar regions when estimating mean temperature changes. As a result, it is not surprising to see small disagreements among the groups.

• Methodology

In reconstructing the changes in global mean temperature since 1850, Berkeley Earth has examined 21 million monthly-average temperature observations from 50,498 weather stations. Of these 18,460 stations and 168,000 monthly averages are available for 2022.

The weather station data is combined with sea surface temperature data from the UK Met Office’s Hadley Centre (HadSST). This ocean data is based on 456 million measurements collected by ships and buoys, including 13 million observations obtained in 2022. We reprocess and interpolate the HadSST data to provide a more complete picture of the oceans. After combining the ocean data with our land data, we arrive at a global picture of climate change since 1850.

Uncertainties arise primarily from the incomplete spatial coverage of historical weather observations, from noise in measurement devices, and from biases introduced due to systematic changes in measurement technologies and methods. The total uncertainty is much less than the long-term changes in climate during the last 170 years.

This report is based on such weather observations as had been recorded into global archives as of early January 2022. It is common for additional observations to be added to archives after some delay. Consequently, temperature analysis calculations can be subject to revisions as new data becomes available. Such revisions are typically quite small and are considered unlikely to alter the qualitative conclusions presented in this report.

This report was prepared by Berkeley Earth. The contents of this report, including all images may be reused under the terms of the Creative Commons BY-NC 4.0  copyright license for any non-commercial purpose and in any forum, consistent with the terms of that license. 

Members of the news media may also use the materials in this report for any news reporting purpose provided that Berkeley Earth is properly acknowledged, without concern for whether or not the CC BY-NC 4.0 license is followed. 

For more information about licensing for commercial purposes, please contact [email protected] .

Updated data files will appear at our data page , and are updated monthly.

In particular, monthly and annual time series are available.

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• Biology Article
• Essay on Global Warming

Essay On Global Warming

Essay on global warming is an important topic for students to understand. The essay brings to light the plight of the environment and the repercussion of anthropogenic activities. Continue reading to discover tips and tricks for writing an engaging and interesting essay on global warming.

Essay On Global Warming in 300 Words

Global warming is a phenomenon where the earth’s average temperature rises due to increased amounts of greenhouse gases. Greenhouse gases such as carbon dioxide, methane and ozone trap the incoming radiation from the sun. This effect creates a natural “blanket”, which prevents the heat from escaping back into the atmosphere. This effect is called the greenhouse effect.

Contrary to popular belief, greenhouse gases are not inherently bad. In fact, the greenhouse effect is quite important for life on earth. Without this effect, the sun’s radiation would be reflected back into the atmosphere, freezing the surface and making life impossible. However, when greenhouse gases in excess amounts get trapped, serious repercussions begin to appear. The polar ice caps begin to melt, leading to a rise in sea levels. Furthermore, the greenhouse effect is accelerated when polar ice caps and sea ice melts. This is due to the fact the ice reflects 50% to 70% of the sun’s rays back into space, but without ice, the solar radiation gets absorbed. Seawater reflects only 6% of the sun’s radiation back into space. What’s more frightening is the fact that the poles contain large amounts of carbon dioxide trapped within the ice. If this ice melts, it will significantly contribute to global warming. 

A related scenario when this phenomenon goes out of control is the runaway-greenhouse effect. This scenario is essentially similar to an apocalypse, but it is all too real. Though this has never happened in the earth’s entire history, it is speculated to have occurred on Venus. Millions of years ago, Venus was thought to have an atmosphere similar to that of the earth. But due to the runaway greenhouse effect, surface temperatures around the planet began rising. 

If this occurs on the earth, the runaway greenhouse effect will lead to many unpleasant scenarios – temperatures will rise hot enough for oceans to evaporate. Once the oceans evaporate, the rocks will start to sublimate under heat. In order to prevent such a scenario, proper measures have to be taken to stop climate change.

More to Read: Learn How Greenhouse Effect works

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• Table Of Contents

Human activity affects global surface temperatures by changing Earth ’s radiative balance—the “give and take” between what comes in during the day and what Earth emits at night. Increases in greenhouse gases —i.e., trace gases such as carbon dioxide and methane that absorb heat energy emitted from Earth’s surface and reradiate it back—generated by industry and transportation cause the atmosphere to retain more heat, which increases temperatures and alters precipitation patterns.

Global warming, the phenomenon of increasing average air temperatures near Earth’s surface over the past one to two centuries, happens mostly in the troposphere , the lowest level of the atmosphere, which extends from Earth’s surface up to a height of 6–11 miles. This layer contains most of Earth’s clouds and is where living things and their habitats and weather primarily occur.

Continued global warming is expected to impact everything from energy use to water availability to crop productivity throughout the world. Poor countries and communities with limited abilities to adapt to these changes are expected to suffer disproportionately. Global warming is already being associated with increases in the incidence of severe and extreme weather, heavy flooding , and wildfires —phenomena that threaten homes, dams, transportation networks, and other facets of human infrastructure. Learn more about how the IPCC’s Sixth Assessment Report, released in 2021, describes the social impacts of global warming.

Polar bears live in the Arctic , where they use the region’s ice floes as they hunt seals and other marine mammals . Temperature increases related to global warming have been the most pronounced at the poles, where they often make the difference between frozen and melted ice. Polar bears rely on small gaps in the ice to hunt their prey. As these gaps widen because of continued melting, prey capture has become more challenging for these animals.

Recent News

global warming , the phenomenon of increasing average air temperatures near the surface of Earth over the past one to two centuries. Climate scientists have since the mid-20th century gathered detailed observations of various weather phenomena (such as temperatures, precipitation , and storms) and of related influences on climate (such as ocean currents and the atmosphere’s chemical composition). These data indicate that Earth’s climate has changed over almost every conceivable timescale since the beginning of geologic time and that human activities since at least the beginning of the Industrial Revolution have a growing influence over the pace and extent of present-day climate change .

Giving voice to a growing conviction of most of the scientific community , the Intergovernmental Panel on Climate Change (IPCC) was formed in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP). The IPCC’s Sixth Assessment Report (AR6), published in 2021, noted that the best estimate of the increase in global average surface temperature between 1850 and 2019 was 1.07 °C (1.9 °F). An IPCC special report produced in 2018 noted that human beings and their activities have been responsible for a worldwide average temperature increase between 0.8 and 1.2 °C (1.4 and 2.2 °F) since preindustrial times, and most of the warming over the second half of the 20th century could be attributed to human activities.

AR6 produced a series of global climate predictions based on modeling five greenhouse gas emission scenarios that accounted for future emissions, mitigation (severity reduction) measures, and uncertainties in the model projections. Some of the main uncertainties include the precise role of feedback processes and the impacts of industrial pollutants known as aerosols , which may offset some warming. The lowest-emissions scenario, which assumed steep cuts in greenhouse gas emissions beginning in 2015, predicted that the global mean surface temperature would increase between 1.0 and 1.8 °C (1.8 and 3.2 °F) by 2100 relative to the 1850–1900 average. This range stood in stark contrast to the highest-emissions scenario, which predicted that the mean surface temperature would rise between 3.3 and 5.7 °C (5.9 and 10.2 °F) by 2100 based on the assumption that greenhouse gas emissions would continue to increase throughout the 21st century. The intermediate-emissions scenario, which assumed that emissions would stabilize by 2050 before declining gradually, projected an increase of between 2.1 and 3.5 °C (3.8 and 6.3 °F) by 2100.

Many climate scientists agree that significant societal, economic, and ecological damage would result if the global average temperature rose by more than 2 °C (3.6 °F) in such a short time. Such damage would include increased extinction of many plant and animal species, shifts in patterns of agriculture , and rising sea levels. By 2015 all but a few national governments had begun the process of instituting carbon reduction plans as part of the Paris Agreement , a treaty designed to help countries keep global warming to 1.5 °C (2.7 °F) above preindustrial levels in order to avoid the worst of the predicted effects. Whereas authors of the 2018 special report noted that should carbon emissions continue at their present rate, the increase in average near-surface air temperature would reach 1.5 °C sometime between 2030 and 2052, authors of the AR6 report suggested that this threshold would be reached by 2041 at the latest.

The AR6 report also noted that the global average sea level had risen by some 20 cm (7.9 inches) between 1901 and 2018 and that sea level rose faster in the second half of the 20th century than in the first half. It also predicted, again depending on a wide range of scenarios, that the global average sea level would rise by different amounts by 2100 relative to the 1995–2014 average. Under the report’s lowest-emission scenario, sea level would rise by 28–55 cm (11–21.7 inches), whereas, under the intermediate emissions scenario, sea level would rise by 44–76 cm (17.3–29.9 inches). The highest-emissions scenario suggested that sea level would rise by 63–101 cm (24.8–39.8 inches) by 2100.

The scenarios referred to above depend mainly on future concentrations of certain trace gases, called greenhouse gases , that have been injected into the lower atmosphere in increasing amounts through the burning of fossil fuels for industry, transportation , and residential uses. Modern global warming is the result of an increase in magnitude of the so-called greenhouse effect , a warming of Earth’s surface and lower atmosphere caused by the presence of water vapour , carbon dioxide , methane , nitrous oxides , and other greenhouse gases. In 2014 the IPCC first reported that concentrations of carbon dioxide, methane, and nitrous oxides in the atmosphere surpassed those found in ice cores dating back 800,000 years.

Of all these gases, carbon dioxide is the most important, both for its role in the greenhouse effect and for its role in the human economy. It has been estimated that, at the beginning of the industrial age in the mid-18th century, carbon dioxide concentrations in the atmosphere were roughly 280 parts per million (ppm). By the end of 2022 they had risen to 419 ppm, and, if fossil fuels continue to be burned at current rates, they are projected to reach 550 ppm by the mid-21st century—essentially, a doubling of carbon dioxide concentrations in 300 years.

A vigorous debate is in progress over the extent and seriousness of rising surface temperatures, the effects of past and future warming on human life, and the need for action to reduce future warming and deal with its consequences. This article provides an overview of the scientific background related to the subject of global warming. It considers the causes of rising near-surface air temperatures, the influencing factors, the process of climate research and forecasting, and the possible ecological and social impacts of rising temperatures. For an overview of the public policy developments related to global warming occurring since the mid-20th century, see global warming policy . For a detailed description of Earth’s climate, its processes, and the responses of living things to its changing nature, see climate . For additional background on how Earth’s climate has changed throughout geologic time , see climatic variation and change . For a full description of Earth’s gaseous envelope, within which climate change and global warming occur, see atmosphere .

ENCYCLOPEDIC ENTRY

Global warming.

The causes, effects, and complexities of global warming are important to understand so that we can fight for the health of our planet.

Earth Science, Climatology

Tennessee Power Plant

Ash spews from a coal-fueled power plant in New Johnsonville, Tennessee, United States.

Photograph by Emory Kristof/ National Geographic

Global warming is the long-term warming of the planet’s overall temperature. Though this warming trend has been going on for a long time, its pace has significantly increased in the last hundred years due to the burning of fossil fuels . As the human population has increased, so has the volume of fossil fuels burned. Fossil fuels include coal, oil, and natural gas, and burning them causes what is known as the “greenhouse effect” in Earth’s atmosphere.

The greenhouse effect is when the sun’s rays penetrate the atmosphere, but when that heat is reflected off the surface cannot escape back into space. Gases produced by the burning of fossil fuels prevent the heat from leaving the atmosphere. These greenhouse gasses are carbon dioxide , chlorofluorocarbons, water vapor , methane , and nitrous oxide . The excess heat in the atmosphere has caused the average global temperature to rise overtime, otherwise known as global warming.

Global warming has presented another issue called climate change. Sometimes these phrases are used interchangeably, however, they are different. Climate change refers to changes in weather patterns and growing seasons around the world. It also refers to sea level rise caused by the expansion of warmer seas and melting ice sheets and glaciers . Global warming causes climate change, which poses a serious threat to life on Earth in the forms of widespread flooding and extreme weather. Scientists continue to study global warming and its impact on Earth.

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UN climate report: It’s ‘now or never’ to limit global warming to 1.5 degrees

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A new flagship UN report on climate change out Monday indicating that harmful carbon emissions from 2010-2019 have never been higher in human history, is proof that the world is on a “fast track” to disaster, António Guterres has warned , with scientists arguing that it’s ‘now or never’ to limit global warming to 1.5 degrees.

Reacting to the latest findings of the Intergovernmental Panel on Climate Change ( IPCC ), the UN Secretary-General insisted that unless governments everywhere reassess their energy policies, the world will be uninhabitable.

#LIVE NOW the press conference to present the #IPCC’s latest #ClimateReport, #ClimateChange 2022: Mitigation of Climate Change, the Working Group III contribution to the Sixth Assessment Report. Including a Q&A session with registered media. https://t.co/iIl81zXev7 IPCC IPCC_CH

His comments reflected the IPCC’s insistence that all countries must reduce their fossil fuel use substantially, extend access to electricity, improve energy efficiency and increase the use of alternative fuels, such as hydrogen.

Unless action is taken soon, some major cities will be under water, Mr. Guterres said in a video message, which also forecast “unprecedented heatwaves, terrifying storms, widespread water shortages and the extinction of a million species of plants and animals”.

Horror story

The UN chief added: “This is not fiction or exaggeration. It is what science tells us will result from our current energy policies. We are on a pathway to global warming of more than double the 1.5-degree (Celsius, or 2.7-degrees Fahreinheit) limit ” that was agreed in Paris in 2015.

Providing the scientific proof to back up that damning assessment, the IPCC report – written by hundreds of leading scientists and agreed by 195 countries - noted that greenhouse gas emissions generated by human activity, have increased since 2010 “across all major sectors globally”.

In an op-ed article penned for the Washington Post, Mr. Guterres described the latest IPCC report as "a litany of broken climate promises ", which revealed a "yawning gap between climate pledges, and reality."

He wrote that high-emitting governments and corporations, were not just turning a blind eye, "they are adding fuel to the flames by continuing to invest in climate-choking industries. Scientists warn that we are already perilously close to tipping points that could lead to cascading and irreversible climate effects."

Urban issue

An increasing share of emissions can be attributed to towns and cities , the report’s authors continued, adding just as worryingly, that emissions reductions clawed back in the last decade or so “have been less than emissions increases, from rising global activity levels in industry, energy supply, transport, agriculture and buildings”.

Striking a more positive note - and insisting that it is still possible to halve emissions by 2030 - the IPCC urged governments to ramp up action to curb emissions.

The UN body also welcomed the significant decrease in the cost of renewable energy sources since 2010, by as much as 85 per cent for solar and wind energy, and batteries.

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• ‘Lifeline’ of renewable energy can steer world out of climate crisis
• 8 reasons not to give up hope - and take climate action

Encouraging climate action

“We are at a crossroads. The decisions we make now can secure a liveable future,” said IPCC Chair Hoesung Lee. “ I am encouraged by climate action being taken in many countries . There are policies, regulations and market instruments that are proving effective. If these are scaled up and applied more widely and equitably, they can support deep emissions reductions and stimulate innovation.”

To limit global warming to around 1.5C (2.7°F), the IPCC report insisted that global greenhouse gas emissions would have to peak “before 2025 at the latest, and be reduced by 43 per cent by 2030”.

Methane would also need to be reduced by about a third, the report’s authors continued, adding that even if this was achieved, it was “almost inevitable that we will temporarily exceed this temperature threshold”, although the world “could  return to below it by the end of the century”.

Now or never

“ It’s now or never, if we want to limit global warming to 1.5°C (2.7°F); without immediate and deep emissions reductions across all sectors, it will be impossible ,” said Jim Skea, Co-Chair of IPCC Working Group III, which released the latest report.

Global temperatures will stabilise when carbon dioxide emissions reach net zero. For 1.5C (2.7F), this means achieving net zero carbon dioxide emissions globally in the early 2050s; for 2C (3.6°F), it is in the early 2070s, the IPCC report states.

“This assessment shows that limiting warming to around 2C (3.6F) still requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by a quarter by 2030.”

Policy base

A great deal of importance is attached to IPCC assessments because they provide governments with scientific information that they can use to develop climate policies.

They also play a key role in international negotiations to tackle climate change.

Among the sustainable and emissions-busting solutions that are available to governments, the IPCC report emphasised that rethinking how cities and other urban areas function in future could help significantly in mitigating the worst effects of climate change.

“These (reductions) can be achieved through lower energy consumption (such as by creating compact, walkable cities), electrification of transport in combination with low-emission energy sources, and enhanced carbon uptake and storage using nature,” the report suggested. “There are options for established, rapidly growing and new cities,” it said.

Echoing that message, IPCC Working Group III Co-Chair, Priyadarshi Shukla, insisted that “the right policies, infrastructure and technology…to enable changes to our lifestyles and behaviour, can result in a 40 to 70 per cent reduction in greenhouse gas emissions by 2050. “The evidence also shows that these lifestyle changes can improve our health and wellbeing.”

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‘Hanging by a Thread’: U.N. Chief Warns of Missing a Key Climate Target

His comments came as the world body’s weather agency said it expected Earth to soon surpass the record high temperatures experienced in 2023.

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By Raymond Zhong

With the planet in the grips of its highest temperatures in more than 100,000 years, scientists with the United Nations weather agency have crunched the numbers and come to a stark conclusion: More record-hot years are all but inevitable.

In the next five years, there’s a nearly 90 percent chance Earth will set yet another record for its warmest year, surpassing the scorching highs experienced in 2023, the World Meteorological Organization said in a report Wednesday .

The chances are almost as great that, in at least one of these five calendar years, the average global temperature will be 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, higher than it was at the dawn of the industrial age. That’s the level of warming that countries set out to avoid under the 2015 Paris Agreement.

“The target of limiting long-term global warming to 1.5 degrees Celsius is hanging by a thread,” the United Nations secretary general, António Guterres, said in a speech on Wednesday at the American Museum of Natural History in New York City. He called for urgent action in a number of areas, including slashing carbon dioxide emissions and adopting renewable energy, helping poor countries finance their climate plans, and clamping down on the fossil fuel industry.

On the last subject, Mr. Guterres reiterated past exhortations to end taxpayer subsidies for oil and gas . But he also turned his attention to a new target: He urged governments to ban advertising by fossil-fuel companies, comparing oil and coal producers to the tobacco industry, which faces advertising restrictions worldwide. And he urged the news media and tech companies to stop displaying their ads.

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• DOI: 10.1007/s00382-024-07300-4
• Corpus ID: 270410046

The changing pattern of global teleconnection and the seasonal precipitation in the High Mountain Asia region

• Soumyadeep Roy , Charu Singh
• Published in Climate Dynamics 10 June 2024
• Environmental Science, Geography

48 References

Emergence of changing central-pacific and eastern-pacific el niño-southern oscillation in a warming climate, validation and comparison of climate reanalysis data in the east asian monsoon region, linking the north atlantic oscillation to winter precipitation over the western himalaya through disturbances of the subtropical jet, validation of era5-land temperature and relative humidity on four peruvian glaciers using on-glacier observations, on the solid and liquid precipitation characteristics over the north-west himalayan region around the turn of the century, a comprehensive validation for gpm imerg precipitation products to detect extremes and drought over mainland china, rising surface pressure over tibetan plateau strengthens indian summer monsoon rainfall over northwestern india, precipitation over southern africa: is there consensus among global climate models (gcms), regional climate models (rcms) and observational data, asymmetric impacts of el niño and la niña on the pacific–north american teleconnection pattern: the role of subtropical jet stream, an appraisal of seasonal precipitation dynamics over the north-west himalayan region under future warming scenarios, related papers.

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• Published: 04 June 2024

Global groundwater warming due to climate change

• Susanne A. Benz   ORCID: orcid.org/0000-0002-6092-5713 1 , 2 ,
• Dylan J. Irvine   ORCID: orcid.org/0000-0002-3543-6221 3 ,
• Gabriel C. Rau 4 ,
• Peter Bayer   ORCID: orcid.org/0000-0003-4884-5873 5 ,
• Kathrin Menberg 6 ,
• Philipp Blum 6 ,
• Rob C. Jamieson 1 ,
• Christian Griebler 7 &
• Barret L. Kurylyk   ORCID: orcid.org/0000-0002-8244-3838 1  

Nature Geoscience volume  17 ,  pages 545–551 ( 2024 ) Cite this article

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• Climate-change impacts
• Projection and prediction

Aquifers contain the largest store of unfrozen freshwater, making groundwater critical for life on Earth. Surprisingly little is known about how groundwater responds to surface warming across spatial and temporal scales. Focusing on diffusive heat transport, we simulate current and projected groundwater temperatures at the global scale. We show that groundwater at the depth of the water table (excluding permafrost regions) is conservatively projected to warm on average by 2.1 °C between 2000 and 2100 under a medium emissions pathway. However, regional shallow groundwater warming patterns vary substantially due to spatial variability in climate change and water table depth. The lowest rates are projected in mountain regions such as the Andes or the Rocky Mountains. We illustrate that increasing groundwater temperatures influences stream thermal regimes, groundwater-dependent ecosystems, aquatic biogeochemical processes, groundwater quality and the geothermal potential. Results indicate that by 2100 following a medium emissions pathway, between 77 million and 188 million people are projected to live in areas where groundwater exceeds the highest threshold for drinking water temperatures set by any country.

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Earth’s climatic system warms holistically in response to the radiative imbalance from increased concentrations of greenhouse gases 1 . While the ocean absorbs most of this additional heat 2 , the terrestrial subsurface and groundwater also function as a heat sink. With a stable climate, seasonal temperature variation penetrates to a depth of 10–20 m, below which temperatures generally increase with depth in accordance with the geothermal gradient 3 . However, present-day borehole temperature–depth profiles frequently show an inversion (that is, temperature decreasing with depth) for up to 100 m due to recent, decadal surface warming 4 . Deviations from steady-state subsurface temperatures in deep boreholes (for example, >300 m) have been used to evaluate terrestrial heat storage and to estimate past, pre-observational surface temperature changes at a global scale 5 . Previous multi-continental synthesis studies on subsurface warming provide critical information on climate dynamics, but impacts on groundwater resources and associated implications are commonly ignored.

With the advent of the Gravity Recovery and Climate Experiment (GRACE) satellites, global datasets and global hydrological models, there is an emerging body of global-scale groundwater research 6 , 7 , 8 , 9 . However, global-scale groundwater studies so far have focused on resource quantity (for example, levels, recharge rates and gravity signals), whereas global-scale research into groundwater quality, including temperature, is rare. Furthermore, prominent syntheses of the relationship between anthropogenic climate change and groundwater (for example, refs. 10 , 11 ) concentrate on quantity leaving quality aspects unexplored 12 . Water temperature, sometimes known as the ‘master environmental variable’ (ref. 13 ), is an understudied groundwater quality parameter in the context of climate change.

Whereas global studies of river and lake warming have been conducted 14 , 15 , there are no global assessments of climate change impacts on groundwater temperatures (GWTs). This is despite the high importance of groundwater, which represents the largest global reservoir of unfrozen freshwater 16 , providing at least part of the water supply for half the world 17 and close to half of the global irrigation demand 18 . It also sustains terrestrial and aquatic ecosystems 19 , particularly in the face of climate change 10 . Given the role of temperature as an overarching water quality variable and observational evidence of groundwater warming in different countries in response to recent climate change 4 , 20 , 21 , the potential impact of climate warming on groundwater temperatures at a global scale remains a critical knowledge gap.

Groundwater temperature influences a suite of biogeochemical processes that alter groundwater quality 22 . For example, an increase in temperatures reduces gas solubility and raises metabolism of organisms, with an increased rate of oxygen consumption and a shift in redox conditions 23 . Because many aquifers already possess low oxygen concentrations, a small change in temperature could trigger a shift from an oxic to a hypoxic or even an anoxic regime 24 , 25 . This switch can in turn facilitate the mobilization of redox-sensitive constituents such as arsenic, manganese and phosphorus 26 , 27 . Increases in soluble phosphorus in groundwater discharging to surface water can trigger harmful algal blooms 28 , and elevated arsenic and manganese contents in potable water supplies pose direct risks to human health 29 . Groundwater warming will also cause a shift in groundwater community composition with a challenge to biodiversity and the risk of an impaired cycling of carbon and nutrients 24 , 25 . Shallow soil and groundwater warming may also cause temperatures in water distribution networks to cross critical thresholds, with potential health implications such as the growth of pathogens such as Legionella spp. 30 .

Diffusive discharge of thermally stable groundwater to surface water bodies modulates their temporal thermal regimes 30 . Also, focused groundwater inflows can create cold-water plumes that provide thermal refuge for stressed aquatic species 31 , including many prize cold-water fish. Accordingly, groundwater warming will increase ambient water temperatures in surface water bodies and the temperatures of groundwater-sourced thermal refuges. Spring ecosystems will also be affected. For example, crenobionts (true spring water species) have a very narrow temperature optimum and tolerance; hence, warming groundwater near the mouths of springs will lead to changes in their reproduction cycles, food web interactions and finally a loss of sensitive species 32 .

Groundwater warming can also have positive effects as the accumulated thermal energy can be recycled through shallow, low-carbon geothermal energy systems 33 . Whereas studies typically focus on recycling the waste heat from anthropogenic sources, particularly from subsurface urban heat islands 34 , the subsurface heat accumulating due to climate change also has the potential to sustainably satisfy local heating demands 35 . However, increased warming will make cooling systems less efficient 36 .

Here we develop and apply a global-scale heat-transport model (thermal diffusion) to quantify groundwater temperatures in space and time and their response to recent and projected climate change (Fig. 1a,b ). Our objective is to reveal the potential magnitude and long-term implications of ongoing shallow groundwater warming and to identify ‘hotspots’ of concern. The model utilizes standard climate projections to drive global groundwater warming down to 100 m below ground surface but with a focus on temperatures at the depth of the water table. We discuss (1) where aquifer warming will influence the viability of shallow geothermal heat recycling in the shallow subsurface (Fig. 1c ), (2) given how it impacts microbial activity and groundwater chemistry, where groundwater temperature may cross key thresholds set by drinking water standards (Fig. 1d ) and (3) where discharge of warmed groundwater will have the most pronounced impact on river temperatures and aquatic ecosystems (Fig. 1e ). Our model is global, and its resolution limits detailed capture of small-scale processes, producing conservative results based on tested hydraulic and thermal assumptions, including realistic advection from basin-scale recharge. More localized processes may lead to higher groundwater temperatures in areas with increased downward flow (for example, river-based recharge) or elevated surface temperatures (for example, urban heat islands) (Supplementary Note 1 provides details).

a – e , Increases in surface air and ground surface temperatures ( a ) drive increases in groundwater temperatures ( b ) that, in turn, impact the geothermal potential for shallow geothermal energy systems ( c ), groundwater chemistry and microbiology, which in turn impacts water quality ( d ) and groundwater-dependent ecosystems ( e ). Figure created with images from the UMCES IAN Media Library under a Creative Commons license CC BY-SA 4.0 .

Groundwater temperatures

We use gridded data to calculate transient subsurface temperature–depth profiles across the globe ( Methods ). Besides past and current temperatures, we present potential (modest mitigation) and worst-case (no mitigation) projections to 2100 based on the Shared Socioeconomic Pathway (SSP) 2–4.5 or SSP 5–8.5 climate scenarios of phase 6 the Coupled Model Intercomparison Project (CMIP6) (ref. 37 ). Results can be accessed and visually explored using an interactive Google Earth Engine app available at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . Figure 2a–c displays maps of mean GWT at the depth of the water table and at 5 and 30 m below ground surface for 2020.

a – c , Map of modelled mean annual temperatures at the depth of the water table ( a ), at 5 m below ground surface ( b ) and at 30 m below ground surface ( c ) in 2020. d , Comparison of modelled and observed groundwater temperatures. Blue markers are (multi-) annual mean temperatures observed between 2000 and 2015 at an unspecified depth against modelled temperatures of the same time period at 30 m depth. Grey markers are temperatures of a single point in time versus modelled temperatures of the same time and depth. A histogram of the errors (observed minus modelled temperatures) is shown in the upper left corner. e , Modelled temperature–depth profiles showing mean annual temperatures and the seasonal envelope for the locations displayed in a . Please note that we use bulk thermal properties, and the water table depth is thus not an input parameter into our model.

Comparison with measured data demonstrates a good accuracy of the model given the global scale with a root mean square error of 1.4 °C and a coefficient of determination of 0.75 (Fig. 2d ). An in-depth discussion on model reliability, uncertainty and limitations is given in Supplementary Note 2 .

The median GWT at the water table in 2020 was 21.0 °C (5.6 °C, 29.3 °C; 10th, 90th percentile; Fig. 2a ). In comparison, using the same ECMWF re-analysis (ERA-5) data product, air temperatures in 2020 were lower at 17.6 °C (1.4 °C, 27.0 °C). This thermal offset is attributable to various processes and conditions including snow pack insulation in colder climates 38 and increased temperatures with depth following the geothermal gradient.

Simulated temperature–depth profiles are displayed at six example locations in Fig. 2e , including their seasonal envelope. Supplementary Note 3 provides a discussion of seasonality. Whereas all locations show an inversion of the temperature–depth profile, the depth at which this thermal gradient ‘inflection point’ (ref. 4 ) is reached varies greatly based on the rate and duration of recent climate change. At the example location in Mexico, temperatures begin to increase with depth (as expected based on the local geothermal gradient) from approximately 10 m downwards, whereas at the example location in Brazil, the inflection point reaches a depth of 45 m (Fig. 2c ). Globally, it has reached 15 (<1, 40) m (Extended Data Fig. 1a ). Heat advection from vertical groundwater flow may also influence the depth of the inflection point 4 , but only heat diffusion is considered in our model as this is the dominant heat-transport mechanism at the modelled spatial scale ( Methods ).

To better assess the impact of recent climate change on groundwater temperatures at the water table depth, we compare annual mean GWTs from 2000 and 2020. Over this 20-year period, GWTs increased on average by 0.3 (0.0, 0.8) °C (Fig. 3a ). We do not find any distinct large-scale patterns. However, some of the highest temperature increases occur in parts of Russia (for example, > + 1. 5 ∘ C north of Novosibirsk), while parts of Canada experienced cooling (for example, < −0. 5 °C in Saskatoon) between the two years. Both regions have shallow water tables, with GWTs tightly coupled to seasonal surface temperature variations and short-term intra-annual changes, rather than just the long-term surface temperature signals. As such, one hot summer can drastically alter the modelled GWT difference between 2000 and 2020. The influence of weather conditions for a given year is also notable in the depth profiles for six selected locations (Fig. 3d ). Noticeable variations occur in the upper 5 m of mean temperature range profiles with temperature changes of 1.1 °C at the location in Australia, compared with 0.5 °C at the location in Nigeria. These effects of intra-annual and short-term interannual variations in weather are attenuated at greater depths (for example, 30 m). Long-term (climate change) effects penetrate deeper, although groundwater warming may be less pronounced with depth due to the time lag between surface and subsurface temperature signals (Fig. 3c ).

a – d , Recent (2000 to 2020) changes. e – h , Projected (2000–2100) changes. a , e , Map of the change in annual mean temperature at the depth of the water table. The line in the legend indicates 0 °C. b , c , f , g , Temperature change 5 m below the land surface ( b , f ) and 30 m below the land surface ( c , g ). d , h , Change in temperatures between 2000 and 2020 ( d ) and difference between 2000 and 2100 ( h ) as depth profiles for selected locations (symbols in a and e ). Lines in h indicate median projections, whereas 25th to 75th percentiles (pct.) are presented as shading.

Over the entire century (between 2000 and 2100), groundwater warming is also projected to increase; globally averaged GWTs at the water table (at its current level) increase by 2.1 (0.8, 3.0) °C following SSP 2–4.5 median projections (Fig. 3e–g ; Extended Data Fig. 2 for 25th (1.7 (0.6, 2.5) °C) and 75th percentile (2.6 (1.0, 3.6) °C) projections) and by 3.5 (1.0, 5.5) °C following SSP 5–8.5 median projections (Extended Data Figs. 3a–d and 4 ; 25th percentile projections 3.0 (0.8, 5.8) °C; 25th percentile projections 4.6 (1.3, 7.1) °C).

We observe a clear signal of climate change by studying the depth down to which the temperature profile is reversed and temperatures are decreasing outside of seasonal effects. In 2100 the geothermal gradient inflection point is projected to reach 45 (9, 90) m on average following SSP 2–4.5 median projections (40 (6, 90) m for 25th percentile and 45 (15, 80) m for 75th percentile projections) or 60 (40, 100) m following SSP 5–8.5 median projections (60 (35, >100) m for 25th percentile and 60 (45, >100) m for 75th percentile projections; Extended Data Figs. 1b,c and 5 ).

Accumulated energy

The overall increase in GWT can be quantified as accumulated energy ( Methods ). By 2020, a net energy amount of 14 × 10 21  J has already been absorbed by the terrestrial subsurface (Fig. 4a ; 119 (45, 202) MJ m −2 ) since the beginning of the industrial revolution. In comparison, 436 × 10 21  J or about 25 times more has been absorbed by the oceans over a similar time period 39 . A review of Earth’s energy imbalance identifies a total heat gain of 358 × 10 21  J for the time period 1971–2018 only, attributing about 6% of that to land areas including permafrost regions (21 × 10 21  J, that is, a similar magnitude as our estimate) 40 . In a similar range is the 23.8 × 10 21  J that was stored in the continental landmass since 1960 following a recent study; 90% is from heat storage 41 .

a – c , Current status in 2020. d – f , Projected status in 2100 under SSP 2–4.5. a , d , Accumulated heat from the surface to 100 m depth. The line in the legend indicates 0 MJ m −2 . b , e , Map showing locations where maximum monthly GWTs at the thermal gradient inflection point (coldest depth) are above guidelines for drinking water temperatures (DWTs) 43 . c , f , GWT changes between 2000 and 2020 ( c ) and between 2000 and 2100 ( f ) at stream sites with a groundwater signature 49 . The line in the legend indicates 0 °C.

We project that by 2100 accumulated subsurface energy will be 41 × 10 21  J following SSP 2–4.5 median projections (343 (251, 463) MJ m −2 ; Fig. 4d ), 30 × 10 21  J following 25th percentile projections (255 (162, 361) MJ m −2 ) and 50 × 10 21  J following 75th percentile projections (424 (324, 560) MJ m −2 ; Extended Data Fig. 6 ). Under SSP 5–8.5 we get 62 × 10 21  J for the median projections (518 (384, 689) MJ m −2 ; Extended Data Fig. 3e ), 49 × 10 21  J for the 25th percentile projections (412 (285, 564) MJ m −2 ) and 77 × 10 21  J for the 75th percentile projections (644 (493, 844) MJ m −2 ; Extended Data Fig. 7 ). This accumulated heat can be extracted from the subsurface through wells in productive aquifers, but in lower-permeability zones and the unsaturated zone, less-efficient borehole heat exchangers would be necessary 33 . Hence, we assessed the energy accumulated in the saturated zone only (below the current water table) in Extended Data Fig. 8 —on average, there is 68 (13, 133) MJ m −2 of heat in the global subsurface saturated zone in 2020.

By comparing the accumulated aquifer thermal energy in the United States (about 45 MJ m −2 ) with local residential heating demands (about 35,000 MJ per household in 2015 following the US Energy Information Administration 2015 Energy Consumption Survey), we find that, if recycled, the energy accumulated below an average home (250 m 2 for the floor area in new single-family houses following the 2015 ‘Characteristics of new housing’ report, US Department of Commerce) in 2020 would fulfil about four months of heating demands. However, by 2100, global heat storage in the saturated zone is projected to increase to 233 (75, 363) MJ m −2 following SSP 2–4.5 and 352 (105, 536) MJ m −2 following SSP 5–8.5 median projections (Extended Data Figs. 8 and 9 for 25th and 75th percentile projections). With heating demands projected to decline due to higher temperatures and improved building insulation, recycling this subsurface heat will therefore become more feasible and is a carbon-reduced heat source that will benefit from climate change 35 . Conversely, cooling systems that rely on geothermal sources will be less efficient.

Implications for drinking water quality

Whereas groundwater warming offers benefits for geothermal heating systems, the accumulated heat also threatens water quality. In many developing countries or in poor and rural areas within developed countries, groundwater may be consumed directly without treatment or storage. It may also indirectly impact temperatures of drinking water within pipes 42 . In these regions in particular, the changes in water chemistry or microbiology that are associated with groundwater warming have to be carefully considered.

According to the World Health Organization, only 18 of 125 countries have temperature guidelines for drinking water 43 . These temperature guidelines, which are often aesthetic guidelines, range from 15 °C to 34 °C, with a median of 25 °C. Figure 4b shows where annual maximum groundwater temperatures at the geothermal gradient inflection point, that is, the most conservative depth as it is the coldest point in the temperature–depth profile, are above these thresholds in 2020. At this time, more than 29 million people live in areas where our modelled maximum GWT exceeded 34 °C. If water is extracted at the depth of the water table, this increases to close to 31 million (Extended Data Fig. 10 ). Following SSP 2–4.5 median projections by 2100, these numbers will increase to 77 million to 188 million depending on the depth of extraction (72 to 101 for 25th percentile projection; 86 to 395 for 75th percentile projections; Fig. 4d and Extended Data Figs. 5 and 9 ). Following SSP 5–8.5 median projections, 59 million to 588 million people will live in areas where maximum GWTs exceed the highest thresholds for drinking water temperatures (54 to 314 for 25th percentile projection; 66 to 1,078 for 75th percentile projections; Extended Data Figs. 3f , 6 and 9 ). Due to the different population distributions, SSP 5–8.5 projects fewer people at risk than SSP 2–4.5 for the lower estimates.

Implications for groundwater-dependent ecosystems

The ecosystems most dependent on groundwater are those in the aquifers themselves. A temperature increase may threaten groundwater biodiversity and ecosystem services 44 , 45 . Also, the increased metabolic rates of microbes caused by warming will accelerate the cycling of organic and inorganic matter, additionally fuelled by the increasing importance of dissolved organic carbon to the subsurface 46 . Combined with decreasing groundwater recharge as projected for many North African, southern European and Latin American countries 47 , this may transform oxic subsurface environments into anoxic 24 .

Groundwater warming also threatens many riverine groundwater-dependent ecosystems and the industries (for example, fisheries) that they support 48 . To capitalize on past continental-scale research related to groundwater, river temperature and ecosystems, we compare our modelled spatial patterns of groundwater warming in the conterminous United States to a recent distributed analysis of 1,729 stream sites 49 . The amplitude and phase of seasonal temperature signals in these surface water bodies were used to reveal the thermal influence and source depth of groundwater discharge to these streams, with about 40% classified as groundwater dominated. Our results show that GWT at the water table for the groundwater-dominated stream sites increased by 0.1 (0.0, 0.4) °C between 2000 and 2020 and 1.3 (0.3, 2.6) °C and 1.9 (0.4, 4.5) °C between 2000 and 2100 following SSP 2–4.5 and SSP 5–8.5 median projections, respectively (Fig. 4c,f and Extended Data Fig. 3g ). Twenty-fifth percentile projections reveal 0.7 (−0.1, 1.5) °C and 1.0 (0.0, 2.9) °C and 75th percentile projections 2.0 (0.5, 4.0) °C and 2.9 (0.6, 6.7) °C between 2000 and 2100 following SSP 2–4.5 and SSP 5–8.5, respectively (Extended Data Figs. 6 and 7 ).

The warming groundwater will inevitably raise the ambient temperature of surface water systems thermally influenced by groundwater discharge. Furthermore, such groundwater warming will even more strongly impact the thermal regimes of groundwater-fed thermal refuges (for example, at the outlets of springs or groundwater-dominated tributaries flowing into rivers) and cause them to more regularly cross critical temperature thresholds for resident species seeking relief from thermal stress. Given the connection between aquifer thermal regimes and river sediment temperatures 50 , groundwater warming also threatens the thermal suitability of benthic ecosystems and spawning areas for fish 51 , posing a major risk to fisheries and other dependent industries.

Summary and model application

In summary, global climate change is leading to increased atmospheric and surface water temperatures, both of which have already been assessed across spatial scales ranging from local to global. Here we contribute to the global analyses of environmental temperature change and of groundwater resources through the presentation of projected groundwater temperature change to 2100 at a global scale. Our analyses are based on reasonable hydraulic and thermal assumptions providing conservative estimates and allow for both the hindcasting and forecasting of groundwater temperatures. Future groundwater temperature forecasts are based on both SSP 2–4.5 and 5–8.5 climate scenarios. We provide global temperature maps at the depth of the water table, 5 and 30 m below land surface, and these highlight that places with shallow water tables and/or high rates of atmospheric warming will experience the highest groundwater warming rates globally. Importantly, given the vertical dimension of the subsurface, groundwater warming is inherently a three-dimensional (3D) phenomenon with increased lagging of warming with depth, making aquifer warming dynamics distinct from the warming of shallow or well-mixed surface water bodies.

To facilitate more detailed future analyses, the temperature maps are included in a Google Earth Engine app at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . The gridded GWT output could be integrated with global river temperature models 52 to more holistically understand future warming in aquifers and connected rivers. Whereas the warming of Earth’s groundwater poses some opportunities for geothermal energy production, it increasingly threatens ecosystems and the industries depending on them, and it will degrade drinking water quality, primarily in less-developed regions.

Diffusive heat transport

We hindcast monthly subsurface temperatures (and therefore also groundwater temperatures (GWTs) based on the assumption of local equilibrium) from the surface to a depth of 100 m for the years 2000 to 2020. We also force our model with future projections following SSP 2–4.5 and SSP 5–8.5 up to the year 2100. Subsurface temperatures in the shallow crust are generally controlled by one-dimensional (1D) (vertical) diffusive heat transport. Heat advection due to water flow plays a lesser and often inconsequential role in controlling subsurface temperatures 54 , 55 , 56 , particularly at larger spatial scales that average out focused groundwater flows in faults and fractures and groundwater exchange with surface water bodies. We adopt our 1D diffusion-dominated approach rather than a 3D numerical model of coupled groundwater flow and heat transfer as there are presently neither the parameterization data nor the computing power to enable such a coupled, 3D water and thermal transport model at a global scale. Also, whereas the influence of heat advection on steady-state or transient, subsurface temperature–depth profiles can be detected with precise temperature loggers and yields valuable insight into vertical groundwater fluxes when heat is used as a groundwater tracer 57 , the rate of shallow groundwater warming is often not thought to be strongly influenced by typical basin-average, vertical groundwater flux rates. Accordingly, heat advection has been ignored in some past local-scale groundwater warming studies (for example, ref. 58 ). However, to further investigate the thermal effects of multi-dimensional flow, we run a suite of scenarios and find that advection only exerts a minor influence on groundwater warming rates for typical groundwater flow conditions (Supplementary Note 1 ), enabling us to employ our approach.

Appropriate initial conditions can be far more important for reliable simulation of temperature–depth profiles than the inclusion of heat advection 59 . To ensure our initial conditions are not influenced by any preceding climate change, we initiate our model in 1880 when the industrial revolution had not yet increased atmospheric greenhouse gasses and the climate was relatively stable. As default initial setting, we define a temperature–depth profile that increases linearly with depth z from the surface T S in accordance with the geothermal gradient a : T ( z ) =  T S  +  a z (ref. 55 ). In permafrost regions, warming above critical thresholds requires latent heat to thaw ground in addition to the sensible heat to raise the temperature. As we do not include latent heat effects, model results are not presented for permafrost regions 60 .

We use the following analytical solution to the transient 1D heat diffusion equation for a semi-infinite homogeneous medium subject to a series of n step changes in surface temperature 55 :

where j is a step change counter (counting by month), t is time, T S ( t ) is the time series of the ground surface temperature, D is the thermal diffusivity and erfc is the complementary error function. This equation is often used in an inverse manner to reconstruct pre-observational ground surface temperature history from observed, deep temperature–depth profiles, demonstrating its utility for investigating the response of subsurface thermal regimes to surface warming.

We run our model in Google Earth Engine (GEE) 61 , and the results are presented in the form of a Google Earth Engine app openly accessible at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles . The application presents zoomable maps of annual mean, maximum and minimum GWT at different depths and seasonal variability (maximum minus minimum) for selected years and climate scenarios. All datasets were created at a native 5 km resolution at Earth’s surface. However, Google Earth Engine automatically rescales images shown on the map based on the zoom level of the user. Charts that represent temperatures at a given location at a 5 km scale are created by clicking on the map and can be exported in CSV, SVQ or PNG file formats. For all analyses showing annual mean data at the water table depth, we first calculate monthly temperatures at the associated monthly groundwater level before averaging the results.

Ground surface temperatures

We use two distinct ground surface temperature time series: (1) one for the analysis of current (2020) temperatures based primarily on the ERA-5 data 62 and (2) one for the analysis of projected changes based on CMIP6 data 37 . On the basis of available computational power and data, we are not able to utilize monthly temperatures for the entire time period between the years 1880 and 2100. Instead, we present monthly temperatures from 1981 onwards and annual mean temperatures for 1880. The threshold 1981 is selected as ERA-5 data were available in Google Earth Engine from this point on when developing the model.

As these data are input into the analytical step function model (equation ( 1 )), we supplement them with mean temperatures of the early 1980s (that is, three-year mean 1981 to 1984) to reduce artefacts of the sudden onset of seasonal signals in our data. An example of the ground surface temperature time series is shown in Supplementary Fig. 11 .

For the analysis of current GWT, we use monthly mean soil temperature at 0–7 cm depth for the years 1981 to 2022 based on the ERA-5-Land monthly average reanalysis product 62 to form the ground surface temperature boundary condition for equation ( 1 ). These data have a native resolution of 9 km at the surface and are available through the GEE data catalogue. We also used annual ground temperature anomalies of 1880 of the top layer following the Goddard Institute for Space Studies (GISS) atmospheric model E 63 . This dataset gives the temperature difference between 1880 and 1980 in a horizontal resolution of 4° × 5° (approximately 444 km × 555 km at the equator) and can be extracted from https://data.giss.nasa.gov/modelE/transient/Rc_ij.1.11.html . To obtain absolute temperatures of 1880, we subtract the anomalies from three-year mean temperatures (1981 to 1984) of the ERA-5 data.

Future projections of ground surface temperatures are based on monthly soil temperatures closest to the surface for scenarios SSP 2–4.5 and SSP 5–8.5 from the CMIP6 programme available from 2015 to 2100. Model selection and methodology follow previous work 64 , but were updated to CMIP6 based on availability. In total we use nine models: BCC-CSM2-MR, CanESM5, GFDL-ESM4, GISS-E2-1-G, HadGEM3-GC31-LL, IPSL-CM6A-LR, MIROC6, MPI-ESM1-2-LR, NorESM2-MM. Where available, we used data from the variant label r1i1p1f1; however, for GISS-E2-1-G and HadGEM3-GC31-LL, these were not available, and we had to use r1i1p1f2 or r1i1p1f3 instead. Furthermore NorESM2-MM was missing data for January 2015; thus, we replaced them with data from December 2014 from the historic scenario. Data were collected from the World Climate Research Programme at https://esgf-node.llnl.gov/search/cmip6/ . In addition, monthly data of the historic scenario were prepared for January 1981 to December 2014 and the annual mean data for 1880. To account for the difference between the CMIP6 models and ERA-5 reanalysis, we adjust the CMIP6 outputs based on mean temperatures \(\overline{T}\) from ERA-5 between 1981 and 2014 (that is, the overlap between ERA-5 and the CMIP6 historic scenario) for each of the CMIP6 models separately as follows:

Temperatures are determined for each model before being presented as the median and the 25th and 75th percentiles.

Thermal diffusivity

For our analysis we use the ground thermal diffusivity D :

where λ (W m −1  °C −1 ) is the bulk thermal conductivity and C V (J m −3  °C −1 ) is the bulk volumetric heat capacity. Ground thermal conductivity and volumetric heat capacity for various water saturation values are derived following previous examples 35 , 65 . This method links λ and C V values for different soil and/or rock types following the VDI 4640 guidelines 66 to a global map of soil and/or rock type. This map is based on grain size information of the unconsolidated sediment map database (GUM) 67 . Where there is no available sediment class, we link to soil type in GUM. When this is also not available, we rely on the global lithological map database (GLiM) 68 . All required datasets were uploaded to Google Earth Engine in their native resolution. For assigned values, refer to Supplementary Table 1 .

We acknowledge that the distribution of subsurface thermal properties is heterogeneous. However, specific heat capacity and thermal conductivity for rocks are both well constrained to within less than half an order of magnitude 69 , 70 compared with the many orders of magnitude for hydraulic conductivity 71 . We also note that water saturation can change the individual thermal properties and have accordingly run our model for six example locations with three different diffusivity values: (1) a dry soil, (2) a moist soil (default) and (3) a water saturated soil (Supplementary Fig. 12 ). The influence of water saturation on thermal diffusivity can be complex as both the heat capacity and thermal conductivity increase with water content (equation ( 3 )). Overall, for locations with unconsolidated material in the shallow subsurface, groundwater warming rates increase with water saturation. However, the effect is nonlinear and the overall impact of water saturation on the thermal diffusivity is negligible for relative saturation values between 0.5 and 1 (ref. 72 ). A map of the diffusivity utilized here is given in Supplementary Fig. 13a .

Geothermal gradient

When advection is absent, the geothermal gradient a (°C m −1 ; equation ( 1 )) is the rate of temperature change with depth due to the geothermal heat flow Q (W m −2 ) and thermal conductivity λ (W m −1  °C −1 ):

with global values for λ derived as described earlier, and the mean heat flow Q available as a global 2° equal area grid (about 222 km at the equator) 73 . Due to their resolution, these data do not incorporate fractures and major faults, and we thus are not able to estimate groundwater temperatures at these locations properly. The grid was uploaded to GEE in its native resolution for analysis (Supplementary Fig. 13b ).

Water table depth

Much of our analysis and interpretation focuses on the future projection of temperatures at the water table depth. We therefore use the results of a previously published global groundwater model 74 , 75 with a 30 sec grid (about 1 km at the equator) to obtain the mean water table depth for 2004 to 2014. These data are available as monthly averages that we uploaded to GEE in their native resolution. In temperate climates, the model underestimates the observed water table depth by 1.5 m, and we therefore set the minimum water table depth to 1.5 m as was done in a previous study 35 . Still, whereas the global-scale hydro(geo)logical model of Fan et al. 74 , 75 can reveal large-scale patterns, it is of limited use for small-scale analysis and must be used with caution. Hence we run additional information for best- and worst-case scenarios where we add or subtract 10 m to the depth of the water table (Supplementary Note 4 ).

To calculate mean annual GWTs at the water table, temperatures for each month were determined at the corresponding water table depth by setting z in equation ( 1 ) to this depth. Future changes of water table elevation are challenging to predict, and we therefore base our analysis on the assumption that future water table elevations are unchanging. If we assume that the water table will rise, then warming would be more extreme; should the water table lower, warming as projected here is overestimated. A more detailed discussion, modelling water table changes of ± 10 m, can be found in Supplementary Note 4 . However, we note that a modelled temperature–depth profile (equation ( 1 )) is not impacted by the choice of the water table depth, and thus the results at 10 and 30 m are independent of the water table model.

Model evaluation

To assess the performance of our GWT calculations, we use two datasets of measured GWT or borehole temperatures. First, we compare our data to (multi-)annual mean shallow GWTs introduced in Benz et al. 35 . These data comprise more than 8,000 individual locations, primarily in Europe, where GWTs were measured at least twice between 2000 and 2015 at less than 60 m depth. Measurements are filtered based on their seasonal radius, a measure describing if a well was observed uniformly over the seasons and mean temperatures are therefore free of seasonal bias 76 . Second, we compare our data to temperature–depth profiles from the Borehole Temperatures and Climate Reconstruction Database at https://geothermal.earth.lsa.umich.edu/core.html . For these data, an exact date and depth of measurement are known. We filter the database based on time of measurement and depth of the first measurement, using only data taken after the year 2000 and starting at less than 30 m depth, resulting in 72 borehole measurements. To evaluate the model, we compare it to the observed groundwater temperatures described above. We compare the shallow (multi-)annual mean temperatures to mean temperatures at 30 m depth (the middle between 0 m and 60 m, the maximum depth of the observations) between 2000 and 2015. For the dataset of one-time borehole temperature–depth profiles, we compare the shallowest data points to temperatures from our model at the same depth (rounded to the nearest metre), month and year.

Example locations

We use six locations distributed over all latitudes as examples in many of our figures, with locations in Australia (longitude 149.12°, latitude −35.28°), Brazil (−47.92°, −15.77°), China (116.39°, 39.90°), Mexico (−99.12°, 19.46°), Norway (10.74°, 59.91°) and Nigeria (7.49°, 9.05°). For convenience, each point is at the location of the capital city. However, as our model is not able to adequately describe the impact of urban heat on measured groundwater temperatures, groundwater at these locations is expected to be warmer, potentially by several degrees. Our focus is on the rate of warming in response to climate change.

Depth of the geothermal gradient ‘inflection point’

To find the depth d i down to which annual mean temperature–depth profiles T ( z ) are inverted (that is, decrease with depth as opposed to increase following the geothermal gradient 4 ), we find the maximum depth where T ( d i ) >  T ( d i +1 ). Given our computational resources, we test this at a resolution of 1-m steps for the first 10 m, then in 5-m steps down to 50 m depth and lastly in 10-m steps down to the maximal depth of 100 m.

To quantify shallow subsurface accumulated energy I (J m −2 ), we compare mean annual temperature–depth profiles down to 100 m depth to the initial conditions T ( z ) =  T S ( t  = 1,880) +  a z by solving the following integral in 1-m steps:

This analysis utilizes annual mean subsurface temperatures \(\overline{T}(z)\) for 2020 or 2100 for the current and projected analyses, respectively. The volumetric heat capacity C V ( z ) of the unsaturated zone (for z above the water table) and the saturated zone (for z below the water table) uses discrete values given in Supplementary Table 1 .

Drinking water temperature thresholds

To assess the impact of groundwater warming on drinking water resources, we compare annual maximum groundwater temperatures to thresholds for drinking water temperatures summarized by the World Health Organization 43 . We do so for temperatures at the depth of the thermal gradient inflection point, the coldest point in the temperature profile and thus a best-case scenario, and for the depth of the water table to capture the 6% to 20% of wells that are no more than 5 m deeper than the water table 77 . To quantify populations at risk of exceeding the threshold, we compare the resulting maps with population counts. For temperatures in 2022, we use the 2015 United Nations-adjusted population density from the Population of World Version 4.11 Model 78 . For future scenarios, we rely on the global population projection grids for 2100 from the SSPs 79 , 80 . These data are available through the socioeconomic data and applications centre.

Impact on surface water bodies

Temperatures in surface water bodies are strongly influenced by atmospheric heat fluxes, but groundwater discharge and other processes can decouple temperatures in the atmosphere and water column. In the United States, 1,729 stream sites have been analysed by Hare et al. 49 to determine the dominance of groundwater discharge and to ascertain the relative depth (shallow or deep) of the associated aquifers. We use these sites to extract changes in mean annual groundwater temperature at the depth of the water table from our results to assess the impact of groundwater warming on these surface water bodies.

Data availability

Raster files (5 km resolution, in the GeoTIFF format) and tables (.CSV) used to create all figures of this study are made available at the Scholars Portal Dataverse at https://doi.org/10.5683/SP3/GE4VEQ (ref. 81 ). An online tool to facilitate exploration of our groundwater temperature model is available at https://susanneabenz.users.earthengine.app/view/subsurface-temperature-profiles .

Code availability

All codes used are also available at the Scholars Portal Dataverse under https://doi.org/10.5683/SP3/GE4VEQ (ref. 81 ). This includes codes written with Jupyter Notebook (Python) and Google Earth Engine (Javascript and GoogleColab/Python) and a detailed description of the process (readme.txt).

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Acknowledgements

S.A.B. was supported through a Banting postdoctoral fellowship, administered by the government of Canada, and since October 2022 as a Freigeist fellow of the Volkswagen Foundation. B.L.K. was supported through the Canada Research Chairs programme. K.M. was supported by the Margarete von Wrangell programme of the Ministry of Science, Research and the Arts Baden-Württemberg (MWK). We thank C. Tissen for sharing data she collected in her study on groundwater temperature anomalies in Europe 53 and the many other people and agencies collecting groundwater temperature data and making them available through (publicly accessible) databases. Without these data, successful validation of our method would not have been possible.

Open access funding provided by Karlsruher Institut für Technologie (KIT).

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Authors and affiliations.

Centre for Water Resources Studies and Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, Canada

Susanne A. Benz, Rob C. Jamieson & Barret L. Kurylyk

Institute of Photogrammetry and Remote Sensing, Karlsruhe Institute of Technology, Karlsruhe, Germany

Susanne A. Benz

Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia

Dylan J. Irvine

School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales, Australia

Gabriel C. Rau

Department of Applied Geology, Martin Luther University Halle-Wittenberg, Halle, Germany

Peter Bayer

Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany

Kathrin Menberg & Philipp Blum

Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria

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Contributions

S.A.B., B.L.K. and D.J.I. designed the study. S.A.B., B.L.K., D.J.I., G.C.R., P. Blum, K.M. and P. Bayer developed the methodology. S.A.B. prepared all data and code for analysis and designed figures. D.J.I. designed Fig. 1 . D.J.I. and G.C.R. designed, performed and led the discussion of the analysis in Supplementary Note 1 . S.A.B., B.L.K., D.J.I. and G.C.R. wrote the manuscript. All authors interpreted results and edited the manuscript together.

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Correspondence to Susanne A. Benz or Barret L. Kurylyk .

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Nature Geoscience thanks Maria Klepikova and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Thomas Richardson, in collaboration with the Nature Geoscience team.

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Extended data

Extended data fig. 1 depth to the inflection point..

Shown is the depth down to which we can trace the impact of climate change in form of inverted temperature-depth profiles, that is temperature is decreasing with depth and not increasing with depth as expected based on the geothermal gradient. a and b , The depth to the geothermal inflection point in 2020 and 2100 following SSP 2-4.5. c , The depth to the geothermal inflection point in 2100 following SSP 5-8.5.

Extended Data Fig. 2 Change in groundwater temperatures following SSP 2-4.5, 25th and 75th percentile projections.

a – f , Map of the change in annual mean temperature between 2000 and 2100 following SSP 2-4.5 at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b and e , Annual mean groundwater temperature 5 m below the surface. c and f , Annual mean groundwater temperature 30 m below the surface. a – c , Annual mean groundwater temperature 25th percentile projected changes. d – f , Annual mean groundwater temperature 75th percentile projected changes.

Extended Data Fig. 3 Change in groundwater temperatures between 2000 and 2100 and implications following SSP 5-8.5.

a , Map of the change in annual mean temperature between 2000 and 2100 following SSP 5-8.5 (median projections) at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b , temperature change 5 m below the surface, and c , 30 m below the surface. d , Change in temperatures between 2000 and 2100 as depth profiles for selected locations. Lines indicate median projections whereas 25th to 75th percentile are presented as shading. e , Accumulated heat down to 100 m depth. The line in the legend indicates 0 MJ per m 2 . f , Map showing locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs). g , GWT changes between 2000 and 2100 at stream sites with a groundwater signature.

Extended Data Fig. 4 Change in groundwater temperatures following SSP5-8.5, 25th and 75th percentile projections.

a and d , Map of the change in annual mean temperature between 2000 and 2100 following SSP5-8.5 at the depth of the water table (under consideration of its seasonal variation). Temperatures in 2000 are based on the historic CMIP6 scenario. The line in the legend indicates 0 ∘ C. b and e , Annual mean groundwater temperature 5 m below the surface. c and f , Annual mean groundwater temperature 30 m below the surface. a to c , Annual mean groundwater temperature 25th percentile projected changes. d to f , Annual mean groundwater temperature 75th percentile projected changes.

Extended Data Fig. 5 Depth to the inflection point for 25th and 75th SSP projections.

The depth down to which we can trace the impact of climate change in form of inverted temperature-depth profiles, that is temperature is decreasing with depth and not increasing with depth as expected based on the geothermal gradient. a and b , The inflection point for SSP2-4.5 in 2100 based on 25th percentile or 75th percentile projections, respecively. c and d , The inflection point for SSP5-8.5 in 20100 based on 25th percentile or rather 75th percentile projections.

Extended Data Fig. 6 Implication of groundwater warming for SSP 2-4.5 25th and 75th percentile projections.

a and d , Accumulated heat down to 100 m depth for SSP 2-4.5 25th and 75th percentile projections, respectively. The line in the legend indicates 0 MJ per m 2 . b and e , Locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs) for SSP 2-4.5 25th and 75th percentile projections, respectively. c and f , GWT changes between 2000 and 2100 at stream sites with a groundwater signature for SSP 2-4.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 7 Implication of groundwater warming for SSP 5-8.5 25th and 75th percentile projections.

a and d , Accumulated heat down to 100 m depth for SSP 5-8.5 25th and 75th percentile projections, respectively. The line in the legend indicates 0 MJ per m 2 . b and e , Locations where maximum monthly GWTs at the thermal gradient inflection point (that is coldest depth) in 2100 are above guidelines for drinking water temperatures (DWTs) for SSP 5-8.5 25th and 75th percentile projections, respectively. c and f , GWT changes between 2000 and 2100 at stream sites with a groundwater signature for SSP 5-8.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 8 Accumulated heat in the saturated zone (that is, below the water table) down to 100 m depth.

a , Accumulated heat in the saturated zone in 2020. b and c , Accumulated heat in the saturated zone in 2100 following median projections of SSP2-4.5 and SSP5-8.5, respectively.

Extended Data Fig. 9 Accumulated heat in the saturated zone (defined as below the water table down to 100 m depth) and maximum temperatures (based on monthly GWTs) at the depth of the geothermal inflection point showing exceedence of guideline thresholds for drinking water temperatures (DWTs) for 25th and 75th percentile SSP projections.

a and b , Accumulated heat in the saturated zone for SSP 2-4.5 25th and 75th percentile projections, respectively. c and d , Locations where maximum temperatures exceed guideline thresholds for drinking water temperatures (DWTs) for SSP 2-4.5 25th and 75th percentile projections, respectively. e and f , Accumulated heat in the saturated zone for SSP 5-8.5 25th and 75th percentile projections, respectively. g and h , Locations where maximum temperatures exceed guideline thresholds for DWTs for SSP 5-8.5 25th and 75th percentile projections, respectively.

Extended Data Fig. 10 Locations where maximum monthly GWTs at the depth of the water table exceed guideline thresholds for drinking water temperatures (DWTs).

a , Maximum monthly GWTs at the depth of the water table in 2020. b and c , Maximum monthly GWTs at the depth of the water table in 2100 following median projections of SSP2-4.5 and SSP5-8.5, respectively.

Supplementary information

Supplementary information.

Supplementary Notes 1–4, Figs. 1–17 and Tables 1–5.

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Benz, S.A., Irvine, D.J., Rau, G.C. et al. Global groundwater warming due to climate change. Nat. Geosci. 17 , 545–551 (2024). https://doi.org/10.1038/s41561-024-01453-x

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Received : 31 May 2023

Accepted : 12 April 2024

Published : 04 June 2024

Issue Date : June 2024

DOI : https://doi.org/10.1038/s41561-024-01453-x

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