This year is now virtually certain to beat 2023 as the hottest year on record, Carbon Brief analysis shows.
It will also be the first full year to surpass 1.5C above pre-industrial levels across the majority of observational records.
In this latest “state of the climate” quarterly update, Carbon Brief finds:
- The year 2024 has seen record warm temperatures for seven of the nine months of the year where data is so far available.
- The world, as a whole, has warmed approximately 1C since 1970 – and 1.2C to 1.4C since the mid-1800s.
- A strong El Niño event contributed to exceptionally high global temperatures early in the year, but record or near-record temperatures persisted despite the fading of El Niño in recent months.
- Record global temperatures have been seen across many regions of the planet over the first nine months of the year.
- Global temperatures are closely aligned with the projections from climate models.
- Global sea ice extent is currently at record lows and Antarctic sea ice has spent much of the year at near-record lows – second only to those seen in 2023.
The warmest year on record
In this latest quarterly state of the climate assessment, Carbon Brief has analysed records from five different research groups that report global surface temperature records: NASA’s GISTEMP; NOAA’s GlobalTemp; Hadley/UEA’s HadCRUT5; Berkeley Earth; and Copernicus/ECMWF.
The figure below shows Carbon Brief’s estimate of where 2024 temperatures will end up in each of the groups, based on the year to date and expected El Niño-Southern Oscillation (ENSO) conditions in the tropical Pacific for the remainder of the year.
The dots reflect the best estimate, while the whiskers show the two sigma (95%) confidence interval of the projections. The prior record year (2023 in all groups) is shown by the coloured square.

Carbon Brief’s project of 2024 annual global average surface temperatures for each group, along with 95% confidence intervals and prior record (2023) values. 1.5C above pre-industrial (1850-1900) levels is shown by a dashed line. The average projection represents a composite of all five records following the WMO approach. Chart by Carbon Brief.
In all cases, the projected global average temperature for 2024 is virtually certain to exceed the prior record set in 2023.
Three of the five groups (Hadley, Berkeley and Copernicus/ECMWF) are very likely to show annual temperatures exceeding 1.5C above pre-industrial levels (defined here as the 1850-1900 period), while the NASA record has a roughly 40% chance of exceeding 1.5C. Only NOAA’s record is unlikely to show global temperatures above 1.5C this year.
These differences in warming since pre-industrial across different datasets primarily result from choice of ocean records used, as well as differences in approaches to filling in gaps between observations in the early part of the records (e.g. pre-1900s). It reflects the uncertainty in the degree of warming since the mid-1800s, with projected 2024 temperatures ranging from 1.44C (NOAA) to 1.61C (Berkeley Earth).
The figure also provides a composite average of the five different datasets, following the approach used in the sixth assessment report (AR6) from the Intergovernmental Panel on Climate Change (IPCC) and by the WMO. Carbon Brief’s analysis finds that 2024 will be the first year above 1.5C in the composite average.
This provides a way to determine the first year where we can reasonably say that the world has passed that warming level – even though 2023 exceeded 1.5C in the Berkeley Earth dataset and 2024 will not exceed 1.5C in the NOAA dataset.
(It is important to note that exceeding 1.5C in a single year is not equivalent to breaching the Paris Agreement limit. The goal is generally considered to refer to long-term warming – typically over two or three decades – rather than annual temperatures that include the short-term influence of natural fluctuations in the climate, such as El Niño.)
The figure below shows the annual temperatures from each of these groups between 1970 and present, with the year-to-date 2024 temperatures for each record shown as individual points.

Annual global average surface temperatures from NASA GISTEMP, NOAA GlobalTemp, Hadley/UEA HadCRUT5, Berkeley Earth and Copernicus/ECMWF (lines), along with 2024 temperatures to date (January-September, coloured shapes). Each series is aligned by using a 1981-2010 baseline, with warming since pre-industrial based on the IPCC AR6 estimate of warming between pre-industrial and the 1981-2010 period. Chart by Carbon Brief.
There is strong agreement between the different temperature records, with all of them showing approximately 1C warming between 1970 and present. Global temperatures have been around 1.3 above pre-industrial levels in recent years (with a range of 1.2C to 1.4C across the different temperature datasets, reflecting that the differences between them are larger in the 1800s and early 1900s).
As the chart below shows, 2024 (purple line) started out remarkably warm as a result of a strong El Niño event that built in 2023 (red) and peaked near the beginning of the year.
However, global temperatures have remained quite elevated despite the fading of El Niño conditions, setting records through June and remaining quite close to 2023’s exceptional highs in recent months.
Overall, 2024 has set or tied all-time records for seven of the 10 months available to-date in the ERA5 record. (This record uses weather model-based reanalysis to combine lots of different data sources over time.)

Temperatures for each month from 1940 to 2024 from Copernicus/ECMWF ERA5. Anomalies plotted with respect to a 1850-1900 baseline. Chart by Carbon Brief.
While human emissions of CO2 and other greenhouse gases are responsible for effectively all of the Earth’s long-term warming, temperatures in any given year are strongly influenced by short-term variations in the Earth’s climate that are typically associated with El Niño and La Niña events.
These fluctuations in temperature between the ocean and atmosphere in the tropical Pacific help make some individual years warmer and some cooler.
The figure below shows a range of different ENSO forecast models produced by different scientific groups. The values shown are sea surface temperature variations in the tropical Pacific – the El Niño 3.4 region – for three-month periods.

Most models expect neutral conditions in the tropical Pacific, with only a few crossing the -0.5C Niño 3.4 sea surface temperature (SST) anomaly that represents the development of a formal La Niña event.
This should result in relatively cooler temperatures in 2025, though it is possible that the year ends up warmer than anticipated given the continuation of high temperatures in recent months – despite the absence of El Niño conditions.
Large areas of record warmth
While global average temperatures are an important indicator of changes to the broader climate system over time as a result of human activities, these impacts will differ as some regions experience more rapid warming or extreme heat events than is reflected in the global average.
The figure below shows the parts of the world that saw record warm or cold temperatures over the first three quarters of 2024 (January through to September) in the Berkeley Earth dataset compared to all prior years since global temperature record began in 1850.

Notably, no area on Earth saw record cold (or even the second, third, fourth or fifth coldest temperatures on record). Nearly all of Central America and large parts of South America saw their warmest year to date on record, as did much of eastern Europe, Africa, China, south-east Asia, and Korea.
The figure below shows the temperature anomaly over the first nine months of the year compared to the 1951-80 baseline period used by Berkeley Earth. Warming was particularly pronounced over land regions, with many areas already showing warming of 1.5C or 2C above that baseline.

Temperatures are tracking 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.
The figure below shows the range of individual models forecasts featured in AR6 – known collectively as the CMIP6 models – between 1970 and 2030, with grey shading and the average projection across all the models shown in black. Individual observational temperature records are represented by coloured lines.

Twelve-month average global average surface temperatures from CMIP6 models and observations between 1970 and 2024. Models use SSP2-4.5 forcings after 2015.Anomalies plotted with respect to a 1981-2010 baseline. Chart by Carbon Brief.
While global temperatures were running below the pace of warming projected by climate models for much of the period between 2008 and 2022, the past two years have been closer to the model average.
However, the CMIP6 models may be biassed a bit too warm, with a subset of “hot” models pushing up the average. The IPCC used an approach that weighted models based on how well they reproduced historical temperatures, rather than simply averaging all the models together.
Excluding these hotter models from the analysis results in observations over recent years much closer to the multi-model average and near the centre of the uncertainty range across all models. It also reveals that the past two years – 2023 and 2024 – have been near the upper end of the model range.

Twelve-month average global average surface temperatures from CMIP5 models and observations between 1970 and 2024. Models use SSP2-4.5 forcings after 2015. Anomalies plotted with respect to a 1981-2010 baseline. Chart by Carbon Brief.
Record low global sea ice extent
Highly accurate observations of Arctic and Antarctic sea ice have been available since polar-observing satellites became available in the late 1970s.
Arctic sea ice extent during the first three-quarters of 2024 has been below or at the low end of the historical 1979-2010 range, but has not seen any record daily lows.
Antarctic sea ice, on the other hand, set new all-time low records for a few days in July and September, and has generally been the second lowest on record (after 2023) from June onwards.
The figure below shows both Arctic (red) and Antarctic (blue) sea ice extent in 2024, the historical range in the record between 1979 and 2010 (shaded areas) and the record lows (dotted black line).
Unlike global temperature records (which only report monthly averages), sea ice data is collected and updated on a daily basis, allowing sea ice extent to be viewed through to the present day.

Arctic and Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The bold lines show daily 2024 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted black lines show the record lows for each pole. Chart by Carbon Brief.
Global sea ice extent is estimated by combining both Arctic and Antarctic sea ice extent. The figure below shows global sea ice extent in each year, with 2024 shown in red. Currently global sea ice extent is at record-low levels, below the prior record for this date set in 2023.

Methodological note
A statistical multivariate regression model was used to estimate the range of likely 2024 annual temperatures for each group that provides a temperature record. This model used the average temperature over the first six months of the year, the average ENSO 3.4 region value during the first nine months of the year and the average predicted ENSO 3.4 value during the last three months of the year to estimate the annual temperatures.
The model was trained on the relationship between these variables and annual temperatures over the period of 1950-2023. The model then uses this fit to predict both the most likely 2024 annual value for each group, as well as the 95% confidence interval. The predicted ENSO 3.4 region values for the last three months of 2024 are taken from the IRI plume forecast.
The percent likelihood of different year ranks for 2024 is estimated by using the output of the regression model, assuming a normal distribution of results. This allows Carbon Brief to estimate what percent of possible 2024 annual values fall above and below the temperatures of prior years for each group, as well as the likelihood of the year exceeding 1.5C in each record.
The post State of the climate: 2024 will be first year above 1.5C of global warming appeared first on Carbon Brief.
State of the climate: 2024 will be first year above 1.5C of global warming
Climate Change
Despite African walkout, fractious land COP ends without drought deal
The African continent’s hopes for a legally binding agreement to combat drought have been dashed again, as UN land restoration talks in Mongolia passed the issue onto the next set of talks in Egypt in two years’ time.
For over a decade, Africa has pushed for a UN protocol on drought risk management that would acknowledge drought as an issue requiring a regional and global – not just a national – response, potentially paving the way for more finance to help ensure water is available when drought hits.
A formal protocol would enable countries to transition from reacting to drought once it hits to “a proactive enabling mechanism to address drought and its effects such as migration”, said a Tunisian negotiator on behalf of the African Group of countries last week. Once land is regularly too dry and infertile to grow crops or graze animals, people often leave to seek a living elsewhere.
But this effort to adopt a protocol, led by Africa, has been resisted at successive land restoration COPs under the UN Convention to Combat Desertification (UNCCD), mainly by developed countries, which argue that a legally weaker alternative – a framework – would be faster and cheaper to set up.
Governments at the previous COP in Saudi Arabia in 2024 failed to reach agreement despite talks running past midnight, while this year’s saw African officials coordinate a walkout from negotiating rooms on Wednesday morning, according to two sources at the talks.
Drought deal delayed until 2028
The IISD’s Earth Negotiations Bulletin, a non-governmental organisation which unlike the media is allowed to watch and report on closed-door talks, said a call to suspend negotiations on Wednesday showed negotiations had reached “boiling point” and “made some jaws drop”.
Negotiations resumed after a lunchtime meeting with the Mongolian COP presidency although governments were only eventually able to agree that they could not find consensus in Ulaanbaatar and should resume talks on an instrument to deal with drought in 2028.
Christine Colvin, WWF’s head of freshwater policy, told Climate Home News that, with droughts hitting from Honduras to the English region of Hampshire, something concrete – whether a protocol or a framework – is needed urgently “rather than the can being kicked down the road for another two years as will now happen with the protocol procrastination”.

But, in a closing press conference on Friday, the Mongolian minister presiding over talks celebrated that governments had reached consensus on several “contentious” issues and that agenda items blocked at this year’s COP17 would be put on the agenda for COP18 in Egypt.
US blocks agenda items
Other agenda items that divided countries were on measuring land degradation’s effects on women, enhancing the involvement of civil society and women in land COPs, and the UNCCD working more closely and effectively with the UN’s climate and nature conventions.
On the COP’s opening day two weeks ago, the US representative said the Trump government objects to these agenda items “on their premise and no amount of negotiation will allow us to join consensus on these items. As such we request that they be struck from the agenda at which time we will then be able to approve it, saving us valuable negotiating time.”
A US State Department spokesperson later told Climate Home News that the US wants the UN “to get back to basics by refocusing on its core mandate, eliminating overlap, and reducing competition for scarce resources”.
The spokesperson added, “that means prioritising the concrete work member states created [the UN] to do – rather than diverting limited time, attention, and resources toward social and political agendas, including gender-related initiatives.”

On COP’s first day, the European Union and Brazil pushed back against the blocking of these agenda items, with a Brazilian negotiator saying his country attaches “great importance” to them. But the Mongolian presidency directed governments to adopt the rest of the agenda without the controversial items, which were discussed privately with countries throughout the two weeks.
An EU statement, read out later by Irish minister Timmy Dooley, accused “some parties” (meaning national governments) of having adopted a “less constructive approach” and preventing “discussions on important matters from even commencing”.
The agenda items the US refused to engage with were never discussed and were only placed onto the agenda for the next COP on the last day. Those talks will take place in Egypt in two years’ time, with Donald Trump due then to be in his last year as US president.
No restoration without women
The blocking of the gender agenda item has stymied attempts, agreed on by governments at the last COP, to develop gender-specific indicators for the UNCCD’s next overall framework and to facilitate more women delegates at COPs. Women made up only about a quarter of delegates to COP15 in 2022, UNCCD analysis with the latest data shows
Criticising the move to keep gender off the agenda, the EU said in a statement that it welcomes “the attention being given at COP17 to women pastoralists and herders, recognising their contribution to sustainable land management and resilient rural livelihoods”.
The head of the UNCCD, former Egyptian environment minister Yasmine Fouad, said on Friday that “regardless that the agenda item was blocked”, she was proud that she and COP17 President Batmunkh Battsetseg had led the COP as women and attended the gender caucus (a meeting of groups supporting women at the talks).

“Without the women,” she told the closing press conference on Friday, “we will not be able to restore land, restore hope, restore life or restore even our children and grandchildren. And we will keep on pushing that agenda.”
The civil society agenda item aimed to allow NGOs to attend land COP negotiations, as they do at climate COPs, and included terms of reference for an Indigenous Peoples Caucus.
A representative of Indigenous Peoples told the COP’s closing plenary meeting that the group had “deep disappointment that the agenda of this COP has removed the dedicated space for indigenous peoples”. “We cannot restore the land while removing the voices of those who care for it,” she said.
On Tuesday, the UNCCD’s deputy head Andrea Meza was asked about Indigenous Peoples’ participation. She said that the blocking of “one agenda item” is “generating uncertainty in the progress” towards creating caucuses for Indigenous Peoples and for Local Communities within the talks.
Because of the “complex geopolitical situation” making it hard to obtain consensus, coalitions of the willing have become more important, she added.
Mining out, money in
Outside the formal negotiations, the summit was marked by a focus on the strongly Mongolian issues of the role played by pastoralists and rangelands like grasslands, as well as mining, in both degrading and restoring land.
Part of the conference was sponsored by Australian mining company Rio Tinto and its local partner Oyu Tolgoi. Their presence was protested by campaigners wearing T-shirts calling on the companies to “stop wasting drinking water” and to “get out of Mongolia”.

The UNCDD and others praised the success of the summit in raising more finance for land restoration. The COP saw institutions like the Asian Development Bank and Global Environment Facility pledge money to combat land degradation, with the UNCCD estimating that $645 million of new commitments were made.
An estimated $355 billion a year is needed through 2030 to meet global land restoration commitments, compared with around $77 billion currently invested. Private finance accounts for only around 6% of global investment, according to the UNCCD.
UNCCD chief scientist Baron Orr told a press conference that many of the announcements were public-private partnerships that use government money to “even the playing field” for companies that want to protect land, in a bid to ensure they are not disadvantaged compared with those that do not.
Such partnerships are a “huge opportunity”, he said, especially as “we’re not in a moment of public finance – public finance is tight in every country.”
The post Despite African walkout, fractious land COP ends without drought deal appeared first on Climate Home News.
Despite African walkout, fractious land COP ends without drought deal
Climate Change
Pacific islands seek backing for new regional fund ahead of COP31
Burdened by rising fuel import costs and an “ocean crisis” of record-breaking heat, Pacific island nations are seeking to build support for a new regional fund ahead of COP31, intended to channel investment into renewable energy, community resilience and ocean protection, experts said.
Leaders from the 18-member Pacific Islands Forum (PIF), including Australia and New Zealand, are expected to issue a call for global pledges to the Pacific Resilience Facility (PRF) at a high-level meeting this coming week in Palau, seeking to build a new model for financing climate action.
The new regional fund was formally launched in May this year and is meant to “serve communities at a community level”, swiftly channelling investments for their projects on the ground, according to Fiji’s assistant minister for foreign affairs, Lenora Qereqeretabua.
“We are expecting pledges for the PRF, and these funds will go to communities that apply,” she told journalists at an online briefing. “We have organised it in such a way that it makes our application processes much, much easier than applying for global funding.”
Qereqeretabua added that she expects that PRF funds will be “utilised by communities to protect themselves from climate change and the effects of climate change.”
The Pacific Islands Forum meeting is expected to shape the region’s priorities ahead of this year’s pre-COP, hosted by Fiji and Tuvalu, and COP31, which will be co-led by Australia and Türkiye.
At COP31, a dedicated session on the climate finance needs of small island states will seek to drive pledges into the PRF. The fund has so far received about $172 million in capital – with about $67 million coming from Australia – and aims to close the year with $500 million.
Ocean heat and fossil fuel shocks
Leaders from the Pacific will meet in Palau from Sunday amid an “ocean crisis” of record-breaking ocean heat caused by this year’s “super El Niño”, according to Kevin Chand, Pacific ocean policy director at National Geographic’s Pristine Seas conservation project.
Leaders at the PIF are expected to put forward commitments towards new marine protected areas, which will be key for shielding ecosystems from future climate extremes, Chand said. The forum is expected to issue a statement on the need for ocean action at COP31, and announce commitments towards reaching the global goal of protecting 30% of the planet’s land and sea ecosystems by 2030.
Rising ocean heat could lead to food insecurity and lost government earnings in the region, as key fish stocks like tuna start migrating away from their coastline in search of colder waters, said Coral Pasisi, director of climate change and sustainability at the Pacific Community (SPC).
Climate shocks are deepening existing economic pressures, as Pacific nations have spent up to a quarter of their GDP on fossil fuel imports due to the war in Iran, according to a recent report by the University of New South Wales (UNSW) in Australia.
Wesley Morgan, one of the study’s authors, told journalists that partner nations “ought to be putting their money where their mouth is”, and should support the energy transition in the Pacific by covering the upfront costs of switching from polluting diesel to solar power, batteries and electricity grid upgrades.
China keeps Indonesia’s battery dream afloat but future less certain
Given the increase in climate-related shocks and sea-level rise, the PIF should also mention the need to phase out fossil fuel extraction and consumption, said Sindra Sharma, international policy lead at the Pacific Islands Climate Action Network (PICAN).
Last year’s COP30 failed to deliver a global roadmap on transitioning away from fossil fuels, which led to a group of countries – including several Pacific island nations – pursuing their own fossil fuel phase-out summit in Santa Marta, Colombia. Next year’s conference will be hosted by Tuvalu and co-chaired by Ireland, which should also receive backing from the PIF, Sharma said.
Both the chairs of the Santa Marta coalition and the Australian COP31 co-presidency have vowed to continue a push for this topic to be discussed at COP31.

New fund to test allies
As local communities in the Pacific struggle to access global climate funds, the PRF’s planned model for quick, direct disbursements has “very solid and good” intentions, Sharma said, but it will need political and financial backing from donor countries.
“The proof is going to be when the fund actually starts operating and delivering to communities,” she added. “If there is too much bureaucracy in being able to access the funds, for example. These things will have to be scrutinised.”
The facility aims to deliver funds in two categories: one for climate adaptation and “disaster resilience”, and another for social and community resilience that includes areas like community capacity-building, education, data analytics and financial management, among others. It will launch its first call for proposals at the PIF.
Morgan added that Australia will need to “leverage global interests” so that funding is directed to the Pacific Resilience Facility “or else the Pacific won’t be able to trust Australia as a partner”. The country ratified the PRF treaty in May, triggering its entry into force.
“The perception [of Australia] in the region is genuinely divided, and it’s worth being honest about it,” Sharma said, adding that the pre-COP31 in Fiji, which is usually limited to a technical space for negotiations, will determine how meaningful Australia’s advocacy for the Pacific can be.
This time, Pacific nations want to use the pre-COP in early October as an opportunity to demonstrate the challenges their largely low-lying islands face and to advocate for their political priorities, including a renewed global effort to limit global warming to 1.5C by cutting emissions faster and deeper. World leaders are due to visit Tuvalu to experience the frontline of rising sea levels, although Australia and Fiji have yet to confirm who will attend.
“In Bonn, Australia was largely missing on the negotiated outcomes that we so urgently need to see. It’s not enough to get Pacific priorities on the agenda. Agenda placement is not delivery,” Sharma added.
The post Pacific islands seek backing for new regional fund ahead of COP31 appeared first on Climate Home News.
Pacific islands seek backing for new regional fund ahead of COP31
Climate Change
Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year
More than 40% of children under the age of 10 globally are already experiencing at least 20 additional “heat-stress days” due to climate change.
This is according to a new attribution study, published in Science Advances, which combines climate models with demographic data to assess the age groups and regions that are exposed to the most hot, humid days.
The study finds that children up to the age of nine already face more additional heat-stress days globally as a result of climate change than any other age group.
It adds that south Asia and west Africa are recording the greatest childhood exposure to dangerous levels of humid heat – largely because these regions have a rapidly growing population with the highest proportion of young children.
As the climate warms, children will continue to be more exposed to heat stress than any other age group, the paper warns.
The lead author of the study tells Carbon Brief that the findings should inform discussions about climate justice, noting that children in developing countries “have contributed the least to historical greenhouse gas emissions”.
Humid heat
High temperatures can be deadly. For example, the heatwaves that swept across Europe in the summer of 2026 have been linked to tens of thousands of “excess deaths”.
A prominent 2021 study found that children born in the 21st century will be exposed to more extreme weather events in their lifetimes than their parents and grandparents.
Four years later, a study conducted by scientists from the same team found that more than half of children born in 2020 – around 62 million people – will experience “unprecedented lifetime exposure” to heatwaves, even if warming is limited to 1.5C.
Now, the latest research from the same team finds that children already face greater exposure to dangerous levels of humid heat than adults as a result of human-caused climate change.
Extreme heat is particularly dangerous when combined with high humidity. In hot weather, the human body produces sweat to cool itself down. However, as humidity increases, sweating becomes less effective.
The study uses wet-bulb globe temperature – a measure of temperature that takes humidity and wind into account – to calculate heat stress. It defines a “heat-stress day” as any day with a wet-bulb globe temperature above 28C, as this is considered the threshold for “moderate heat stress”
The authors then use climate models to simulate global temperature patterns in the present-day climate. (The authors use the climate of 2023, in which human activity has caused 1.3C of warming, to represent the “present-day”.)
They then count the number of heat-stress days that each country records on average, per year. The authors then repeat this exercise, simulating a pre-industrial climate without human-caused warming.
By comparing the number of heat-stress days in the present-day climate with the number in a pre-industrial climate, the authors can determine how many extra heat-stress days were driven by climate change. They refer to these as “extra” or “attributable” heat-stress days.
The authors find that “low-latitude” countries, located in the tropics, record the most extra heat-stress days.
For example, the paper finds that people living in Côte d’Ivoire currently face 112 heat-stress days every year. It adds that around half of these are due to human-caused climate change.
In contrast, Germany sees only 0.1 heat-stress days per year in today’s climate on average, which is largely attributable to human-caused climate change.
Rosa Pietroiusti, a PhD student at Vrije Universiteit Brussel and lead author on the study, explains why this number may seem lower than expected.
She tells Carbon Brief that the paper “really focuses on humid heat, at levels that are relatively rarely felt in Europe”. She adds:
“Our data also doesn’t capture the urban heat island effect, due to the resolution of the data we use, which also would lead to underestimations of heat stress locally, and lead to a mismatch with what people are experiencing at local scales, particularly in cities.”
Inequality
Extreme heat affects some people more severely than others. Children, people over 65 and those with pre-existing medical conditions or certain disabilities are among the most vulnerable. This is because their bodies are less able to regulate their temperature.
The authors use gridded demographic data to determine the age structure of each country. From this, they calculate how many people from each age cohort are exposed to extra heat days as a result of climate change.
The research finds that globally, 583 million children under the age of 10 already live through at least 20 attributable heat days every year. This accounts for 44% of all children in this age bracket.
In comparison, 190 million people aged 60-69 face at least 20 attributable heat days per year, accounting for 30% of this age cohort.
The authors find that children face the greatest exposure to humid heat for two main reasons.
First, there are more young people alive today than older people, with 1.3 billion children aged under 10 in the world, compared to 0.6 billion people aged 60-69.
Second, they find that countries in Africa and Asia typically have rapidly growing populations with more young children. In contrast, many countries in the northern hemisphere – which are typically cooler – have older populations.
The map below shows how many extra stress heat days each country currently faces as a result of human-caused climate change. Darker reds indicate a higher number of attributable heat days. The blue circles show the percentage of the population under the age of 10, with larger circles indicating a higher percentage.

Warming world
The authors also repeat their analysis for a 1.5C and 2C warmer world. They use population estimates from the SSP2 scenario, which projects that the world’s population will peak at more than nine billion in the second half of the 21st century, with most growth occurring in low-latitude regions – especially in sub-Saharan Africa.
The research finds that, in today’s climate, 11% of all under 10s currently experience 100 or more extra heat-stress days per year due to climate change. In worlds warmed by 1.5C and 2C, the percentage rises to 13% and 23%, respectively.
In contrast, only 6% of all people aged 60-69 currently face 100 or more extra heat-stress days each year due to climate change. This number rises to 9% and 17% for 1.5C and 2C worlds, respectively.
These results are shown in the plot below. The three rows represent the climates of 2023 (top), a 1.5C world (middle) and a 2C world (bottom). The columns show different age cohorts, from the oldest on the left to the youngest on the right.
Each circle contains 100 coloured dots, with each dot representing 1% of the age cohort.
The colour of the dot represents exposure to annual heat-stress day, with darker dots indicating more heat-stress days. Grey dots mean that people experience fewer than one extra heat-stress day per year due to human-caused climate change, while black dots mean more than 150 extra heat-stress days due to climate change.
The figure shows that higher warming levels expose more people to heat stress and that younger cohorts tend to be worst affected.
For example, the top-right circle represents heat stress for under 10s in the present-day climate. Three of these dots are coloured black, indicating that 3% faced at least 150 attributable heat-stress days in 2023.

Pietroiusti tells Carbon Brief the study uses wet-bulb temperature because it is a “well-established heat stress metric”. However, she notes that it was not “explicitly defined to focus on children”. She continues:
“A really important step forward in the research community would be to link up climate science and health science experts to do research on what metrics are really most representative of, for example, health impacts and educational impacts that children will be suffering.”
Vulnerability
Dr Qinqin Kong, a postdoctoral researcher at the departments of medicine and health policy at Stanford University, who was not involved in the study, praises its “robust” methodology.
He tells Carbon Brief that the research provides “a timely quantitative evidence for discussions of climate justice, children’s rights and intergenerational equity”.
However, Kong suggests that the paper “may overstate the contrast between children and the elderly and underestimate the relative burden of older adults”.
He says:
“The elderly may also be more vulnerable due to their social circumstances. Children often benefit from parental supervision and caregiving, whereas many older adults live alone, have limited mobility and face barriers to accessing cooling or emergency assistance during heat events.”
Kong also notes that “people and societies in the mid-latitudes [for example, across much of Europe and North America] are less adapted to heat”, which may make them vulnerable to its impacts.
For example, he says that Europe “shows substantially stronger relative risk of heat mortality likely due to less heat-acclimatised populations, lower air conditioning prevalence and urban designs that don’t favour heat dissipation”.
Similarly, Dr Daniel Vecellio – a researcher at the University of Nebraska, who was not involved in the study – tells Carbon Brief that children are an “understudied cohort”.
However, he says there is “reason for hope” because “children are typically pretty good behavioural adapters to extreme heat” and because people who are “chronically exposed to extreme heat” will “have a better chance at better acclimatisation”.
Pietroiusti tells Carbon Brief that global reporting on heatwaves is often skewed towards wealthier nations.
For example, she notes that large-scale databases of disasters, such as EM-DAT, often underrepresent heatwaves in Africa, due in part to a lack of news coverage and formal reporting. She adds:
“Studies like this, which start from the climate data, can start to fill some of these gaps.”
She adds that the paper should inform discussions about climate justice, noting that children in developing countries, who are most severely affected by the increase in heat-stress days, “have contributed the least to historical greenhouse gas emissions”.
Pietroiusti, R. et al. (2026) Age-specific exposure to human-induced increases in humid heat, Science Advances, doi:10.1126/sciadv.aeb3232
The post Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year appeared first on Carbon Brief.
Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year
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