The year 2023 saw the coronation at Westminster Abbey of a new king, the mugshot of a former US president and the rebranding of a social media platform to a single letter.
But behind the biggest stories of the year, thousands of studies detailing new research also made the headlines. And climate change and energy were among the topics that received the most attention.
Each year, Altmetric tracks how often research papers from academic journals are mentioned in online news articles as well as on blogs and social media platforms. It then gives each paper a score according to the attention it receives.
Using Altmetric data for 2023, Carbon Brief has compiled its annual list of the 25 most talked-about climate- or energy-related papers that were published the previous year.
(The list focuses on peer-reviewed research papers only – commentaries or other papers that are not formally peer-reviewed are not included.)
The infographic above shows which papers made it into the top 10, while the article includes analysis of the full list of 25, including the diversity of their authors and which journals feature most frequently.
The list covers research into the climate projections of a major oil company, the human cost of global warming and the catastrophic failure of breeding penguins – as well as the curious case of the high-scoring paper that received almost no news coverage at all.
Antarctic ice shelves
The most talked-about journal papers of 2023 are again dominated by research relating to Covid-19, continuing the pattern seen in recent years.
For example, the highest-scoring paper of any published in 2023 is a review into the effectiveness of measures to reduce the spread of respiratory viruses, such as Covid, swine flu and severe acute respiratory syndrome (Sars).
The study’s Altmetric score of 25,730 puts it almost 10,000 points ahead of the second-placed paper, which is also about Covid.
But the top-scoring paper relating to climate is not far behind, landing fourth in the overall list with a score of 13,886.
The study, “Change in Antarctic ice shelf area from 2009 to 2019”, gains the highest score for any climate paper in any of Carbon Brief’s annual reviews by some distance – the previous highest was 7,803 in 2022.
(For Carbon Brief’s previous Altmetric articles, see the links for 2022, 2021, 2020, 2019, 2018, 2017, 2016 and 2015.)
The study, published in the Cryosphere, uses satellite observations to produce a dataset of changes in the “calving front” – that is, where icebergs break off – and area of the ice shelves that surround Antarctica between 2009 and 2019. It shows that, overall, the area of Antarctic ice shelves has grown by around 5,300 square kilometres (km2) since 2009, with 18 ice shelves retreating and 16 larger shelves growing in area.
Specifically, ice-shelf area has decreased on the Antarctic Peninsula (by 6,693km2) and in west Antarctica (by 5,563km2), and increased in east Antarctica (by 3,532km2) and on the large Ross and Ronne-Filchner ice shelves (by 14,028km2), the paper says.
The map from the study below shows the growth (blue) and retreat (red) of ice shelves around Antarctica, where the size of the circles indicates the scale of the change from 2009 to 2019.
While the high scores of climate-related papers in previous years have primarily been driven by news coverage, this paper appears in just seven news stories.
As study author Prof Anna Hogg from the University of Leeds explains to Carbon Brief:
“Somewhat unusually, we didn’t put out a press release for the paper as we assumed the scientific community that needed the dataset would make use of it naturally.”
Instead, the paper’s high Altmetric score is principally a result of a huge number of mentions on Twitter – more than 63,000 posts from around 48,000 accounts. (Altmetric includes weightings in its scoring system, so news articles (with a weighting of eight) are deemed to have more impact than tweets (0.25).)
A closer look suggests that the paper has been widely quoted by the Twitter accounts of a number of prominent climate sceptics in an attempt to push back on concerns around climate change and the loss of Antarctic ice. These posts have then been widely retweeted by other accounts.
To see the paper “being used as evidence to suggest that climate change isn’t happening” was a “real surprise”, says Hogg, because the paper “doesn’t make any such statement”.
Specifically, the gains the study identifies in ice-shelf area in east Antarctica do not detract from the risks of retreating ice shelves on other parts of the continent, says Hogg:
“The decrease in ice shelf area in west Antarctica is particularly important as this ice shelf area actively ‘buttresses’ the flow of ice from the ice sheet behind it, which through ice dynamic processes is one of the reasons why west Antarctica is contributing significantly to present-day sea level rise.”
Indeed, the seventh most-talked about paper in 2023 (see below) is a Nature Climate Change study warning that accelerated melt of west Antarctica’s ice shelves is now locked in, even for the most ambitious emissions reduction scenarios. The authors provide this stark conclusion:
“These results suggest that mitigation of greenhouse gases now has limited power to prevent ocean warming that could lead to the collapse of the west Antarctic ice sheet.”
The misleading way the study has been used by some climate-sceptic social media accounts has been “incredibly challenging”, says Hogg, with the authors unable “to reply to every incorrect tweet” about their work. However, they did find “a fair number” of responses from other accounts “saying that they had read the paper and it didn’t provide evidence against climate change”.
This perhaps shows “open access doing its job”, says Hogg, as the paper was published in an open-access journal and so is freely available for anyone to read. In another high-scoring statistic, the full paper has now been viewed more than 150,000 times on the journal’s website.
ExxonMobil
Landing in second place with an Altmetric score of 8,686 is the review paper, “Assessing ExxonMobil’s global warming projections”. Published in Science, the study analyses the global warming projections documented and modelled by scientists at the oil major ExxonMobil between 1977 and 2003.
(There is a higher-scoring paper, “The 2023 state of the climate report: Entering uncharted territory”, in the journal BioScience, but it is a “special report” and was not formally peer reviewed.)
The results indicate that “in private and academic circles since the late 1970s and early 1980s, ExxonMobil predicted global warming correctly and skillfully”, the paper says, adding:
“ExxonMobil’s average projected warming was 0.20C ±0.04C per decade, which is, within uncertainty, the same as that of independent academic and government projections published between 1970 and 2007.”
The findings reveal that ExxonMobil “knew as much as academic and government scientists knew” about global warming decades ago. But, the paper adds, “whereas those scientists worked to communicate what they knew, ExxonMobil worked to deny it”.
The study was covered by 823 news stories by 555 outlets, including BBC News, the Associated Press, CNN, Vice, CNBC and Inside Climate News. It was also included in 48 blog posts and more than 13,000 tweets. It is the 12th most talked-about paper on any topic in 2023.
Extreme heat
In third place is the Nature Medicine paper, “Heat-related mortality in Europe during the summer of 2022”, with a score of 7,821. The study finds that more than 60,000 deaths in the summer of 2022 – Europe’s hottest season on record – were linked to the heat.
Across 35 countries, the highest numbers of heat-related deaths occurred in Italy (18,010 deaths), Spain (11,324) and Germany (8,173), the study says. It also finds that the “burden of heat-related mortality was higher among women”, with 56% more heat-related deaths in women than men, relative to population.
The study was picked up in 943 news stories from more than 650 outlets – the largest number of any paper in the top 25. It was picked up by outlets across Europe, including Sky News and ITV News in the UK, Agence France-Presse in France and Der Spiegel in Germany. Carbon Brief also covered the article in detail.
The widespread coverage was likely to be in part because Europe was experiencing a heatwave dubbed “Cerberus” when the paper was published in July.
Lead author Dr Joan Ballester Claramunt from the Barcelona Institute for Global Health tells Carbon Brief that the paper also “received so much attention from the media because society is increasingly aware of the health risks of environmental factors, and particularly in a context of rapidly warming temperatures”.
Rest of the top 10
In fourth place is, “Warning of a forthcoming collapse of the Atlantic Meridional Overturning Circulation”, which was published in Nature Communications.
The study uses statistical techniques to detect early warning signs of a shutdown in the Atlantic Meridional Overturning Circulation (AMOC), one of the major current systems in the world’s oceans that plays a crucial role in regulating climate.
While assessments using climate model simulations typically suggest that AMOC is “unlikely” to pass a tipping point within the 21st century, the study says a collapse could occur “around mid-century under the current scenario of future emissions”.
(Another paper that also uses observation-based early warning signals to assess the stability of AMOC featured in second place in Carbon Brief’s leaderboard for 2021.)
The paper’s Altmetric score of 6,216 reflects its widespread news coverage, covering 672 stories from more than 500 outlets, including the Washington Post, Politico, El País, CNN and Der Spiegel.
The papers in fifth and ninth place both set out frameworks for assessing “safe” boundaries for the Earth to be a habitable place for humans.
In fifth place with a score of 5,411 is the Science Advances paper, “Earth beyond six of nine planetary boundaries”. Providing the latest assessment of the boundaries that were first established in 2009, the paper warns that “Earth is now well outside of the safe operating space for humanity”.
The ninth-placed paper, “Safe and just Earth system boundaries”, shares a number of the same authors and sets out to quantify limits for “climate, the biosphere, water and nutrient cycles and aerosols at global and subglobal scales”. When the paper was published in May, Carbon Brief reported on the mixed reaction the paper received from other scientists, including concerns that a “self-selected group of scientists” were defining the “safe space” for the planet.
In sixth place is the Science paper, “Global glacier change in the 21st century: Every increase in temperature matters”, which reveals a “strong linear relationship between global mean temperature increase and glacier mass loss”.
The study projects that glaciers outside of Antarctica and Greenland will lose between 26% and 41% of their collective mass by 2100, relative to 2015, under warming of 1.5C to 4C, respectively. Such a loss would cause 49-83% of glaciers to disappear and see 90-154mm added to global sea levels, the study says.
In seventh place is the Nature Climate Change paper, “Unavoidable future increase in West Antarctic ice-shelf melting over the 21st century”, as mentioned above. The findings, the authors say, present a “sobering outlook” for ice shelves in the Amundsen Sea.
The paper made an appearance in the Science round of Carbon Brief’s annual quiz.
The eighth-placed paper is, Quantifying the human cost of global warming, published in Nature Sustainability. It quantifies this cost in terms of the number of people left outside the “climate niche” in which human civilisation has flourished for centuries.
The study shows that climate change has already put around 9% of people outside this niche, and that, by end-of-century, current policies leading to around 2.7C global warming could leave 22-39% of people outside the niche as well.
Finally, rounding out the top 10 is, “Climate extremes likely to drive land mammal extinction during next supercontinent assembly”, in Nature Geoscience.
The study looks at the prospects for humans and other mammals on Earth based on first-ever supercomputer climate modelling of the distant future. The knock-on impacts of all Earth’s continents eventually converging to form the supercontinent “Pangea Ultima” would see huge amounts of CO2 released into the air through volcanic eruptions, it says.
The resulting global temperatures of up to 75C would, as a headline in the i newspaper put it, “one day wipe out humanity – but not for another 250m years”.
Elsewhere in the top 25
The rest of the top 25 includes a mix of research, including a paper on the impacts of El Niño on economic growth, a study on the environmental impacts of different types of diets and analysis of the amount of global warming still “in the pipeline” by former Nasa scientist Dr James Hansen.
In 14th place is the Nature paper, “Assessing the size and uncertainty of remaining carbon budgets”, which presents an updated estimate of the remaining carbon budget for limiting warming to 1.5C and 2C.
In a 2022 Carbon Brief guest post, some of the study authors present a similar analysis, concluding that the remaining carbon budget to limit warming to 1.5C could be just 260bn tonnes of CO2 (GtCO2) – the equivalent of around six years of emissions. They add:
“Cutting global CO2 emissions to zero by 2050, in line with limiting warming to 1.5C, would require them to fall by about 1.4GtCO2 every year, comparable to the drop in 2020 as a result of Covid-19 lockdowns around the world, but this time driven by a long-term, structural change of the economy.
“This highlights that the scale of the challenge is immense, no matter the precise figure of the rapidly shrinking carbon budget.”
Antarctic sea ice made headlines around the world both in 2022 and 2023, by setting two consecutive years of record low sea ice extent. In August 2023, researchers published a sobering study in Communications Earth and Environment under the title, “Record low 2022 Antarctic sea ice led to catastrophic breeding failure of emperor penguins”.
The study finds that melting ice led to widespread “breeding failure” across Antarctic emperor penguin colonies and received widespread media attention. It has been mentioned in 537 news articles, generating headlines such as, “Thousands of penguins die in Antarctic ice breakup”, from BBC News and, “Thousands of penguin chicks killed by early sea ice breakup, study says”, in the Washington Post.
The Guardian, New Scientist and Daily Telegraph were among the other publications that reported on the study. This surge of attention pushed the paper to 15th in the Carbon Brief ranking, with an Altmetric score of 3,551.
Meanwhile, the Lancet Countdown on health and climate change slipped down the rankings this year. After three years in the Carbon Brief’s top 10, this year’s report lands in 20th place with an Altmetric score of 3,191.
The report is an epic annual publication, which reviews vast swathes of literature and has more than 100 authors this year. This year’s report introduced some key new indicators of the links between climate change and human health. It was also the first to include projections on how the indicators might worsen in a warmer world.
The report finds that loss of labour due to heat exposure resulted in a $863bn loss of “potential income” in 2022. The agriculture sector was hit the hardest by the loss of labour, accounting for 82% of losses in least developed countries, the authors add.
Carbon Brief’s coverage of the report highlights this loss of income due to heat stress. The graph below shows effective income losses in 2022 due to heat stress in agriculture (blue) and other sectors (red), as a percentage of GDP, by continent.
One spot below the Lancet report is a Geophysical Research Letters study which warns that climate change is making air turbulence stronger and more frequent. The findings, which were picked up in more than 500 news articles, have worrying implications for aircraft passengers.
Back in 2017, study author Dr Paul Williams wrote a Carbon Brief guest post warning that “the most severe [type of turbulence] – the kind that can launch passengers out of their seats and cause serious injuries – is set to become twice or even three times as common by the latter half of the century”. And a recent Carbon Brief guest post on the fastest jet stream winds – known as “jet streaks” – also forecasts an increase in clear-air turbulence for aircraft passengers.
And in 24th place is the Nature paper, “Glacial lake outburst floods threaten millions globally”, with an Altmetric of 2,991. The study warns that 15 million people globally are exposed to impacts of potential “glacial lake outburst floods” (GLOFs). (For more on GLOFs, see Carbon Brief’s guest post from 2020, which explains how lakes formed by melting glaciers around the world have increased in size by 50% over the past 30 years.)
Top journals
This year there is a clear winner for the journal with the most papers featuring in Carbon Brief’s top 25: Science takes top spot with five papers.
Following Science are the three journals of Nature Climate Change, Nature Communications and the Lancet, each with two papers in the top 25.
For the rest of the top 25, the remaining 14 journals appear once each.
All the final scores for 2023 can be found in this spreadsheet.
Diversity of the top 25
The top 25 climate papers of 2023 cover a huge range of topics and scope. However, despite the variety in the climate research the papers present, analysis of their authors reveals a distinct lack of diversity.
In total, the top 25 climate papers of 2023 have more than 440 authors. Carbon Brief recorded the gender and country of affiliation for each of these authors. (The methodology used was developed by Carbon Brief for analysis presented in a special 2021 series on climate justice.)
The analysis reveals that the authors of the climate papers most featured in the media in 2023 are predominantly men from the global north.
The chart below shows the institutional affiliations of all authors in this analysis, broken down by continent – Europe, North America, Oceania, Asia, South America and Africa.
The analysis shows that nine out of every 10 authors are affiliated with institutions from the global north – defined as North America, Europe and Oceania. Meanwhile, only six authors are from Africa and South America.
Further data analysis shows that there are also inequalities within continents. The map below shows the percentage of authors from each country in the analysis, where dark blue indicates a higher percentage. Countries that are not represented by any authors in the analysis are shown in white.
The top-ranking countries on this map are the UK and the US, which together account for almost half of all authors in this analysis (25% and 18%, respectively).
More than half of all researchers from the global south are from China – which accounts for around 6% of all researchers in the analysis.
Meanwhile, only one-third of authors from the top 25 climate papers of 2022 are women. Similarly, only seven of the 25 papers have a female lead author.
The plot below shows the number of male (purple) and female (orange) authors in this analysis from each continent.
The full spreadsheet showing the results of this data analysis can be found here. For more on the biases in climate publishing, see Carbon Brief’s article on the lack of diversity in climate-science research.
The post Analysis: The climate papers most featured in the media in 2023 appeared first on Carbon Brief.
Analysis: The climate papers most featured in the media in 2023
Greenhouse Gases
Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate
We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.
This is an online version of Carbon Brief’s fortnightly Cropped email newsletter.
Subscribe for free here.
Key developments
Food inflation on the rise
DELUGE STRIKES FOOD: Extreme rainfall and flooding across the Mediterranean and north Africa has “battered the winter growing regions that feed Europe…threatening food price rises”, reported the Financial Times. Western France has “endured more than 36 days of continuous rain”, while farmers’ associations in Spain’s Andalusia estimate that “20% of all production has been lost”, it added. Policy expert David Barmes told the paper that the “latest storms were part of a wider pattern of climate shocks feeding into food price inflation”.
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NO BEEF: The UK’s beef farmers, meanwhile, “face a double blow” from climate change as “relentless rain forces them to keep cows indoors”, while last summer’s drought hit hay supplies, said another Financial Times article. At the same time, indoor growers in south England described a 60% increase in electricity standing charges as a “ticking timebomb” that could “force them to raise their prices or stop production, which will further fuel food price inflation”, wrote the Guardian.
‘TINDERBOX’ AND TARIFFS: A study, covered by the Guardian, warned that major extreme weather and other “shocks” could “spark social unrest and even food riots in the UK”. Experts cited “chronic” vulnerabilities, including climate change, low incomes, poor farming policy and “fragile” supply chains that have made the UK’s food system a “tinderbox”. A New York Times explainer noted that while trade could once guard against food supply shocks, barriers such as tariffs and export controls – which are being “increasingly” used by politicians – “can shut off that safety valve”.
El Niño looms
NEW ENSO INDEX: Researchers have developed a new index for calculating El Niño, the large-scale climate pattern that influences global weather and causes “billions in damages by bringing floods to some regions and drought to others”, reported CNN. It added that climate change is making it more difficult for scientists to observe El Niño patterns by warming up the entire ocean. The outlet said that with the new metric, “scientists can now see it earlier and our long-range weather forecasts will be improved for it.”
WARMING WARNING: Meanwhile, the US Climate Prediction Center announced that there is a 60% chance of the current La Niña conditions shifting towards a neutral state over the next few months, with an El Niño likely to follow in late spring, according to Reuters. The Vibes, a Malaysian news outlet, quoted a climate scientist saying: “If the El Niño does materialise, it could possibly push 2026 or 2027 as the warmest year on record, replacing 2024.”
CROP IMPACTS: Reuters noted that neutral conditions lead to “more stable weather and potentially better crop yields”. However, the newswire added, an El Niño state would mean “worsening drought conditions and issues for the next growing season” to Australia. El Niño also “typically brings a poor south-west monsoon to India, including droughts”, reported the Hindu’s Business Line. A 2024 guest post for Carbon Brief explained that El Niño is linked to crop failure in south-eastern Africa and south-east Asia.
News and views
- DAM-AG-ES: Several South Korean farmers filed a lawsuit against the country’s state-owned utility company, “seek[ing] financial compensation for climate-related agricultural damages”, reported United Press International. Meanwhile, a national climate change assessment for the Philippines found that the country “lost up to $219bn in agricultural damages from typhoons, floods and droughts” over 2000-10, according to Eco-Business.
- SCORCHED GRASS: South Africa’s Western Cape province is experiencing “one of the worst droughts in living memory”, which is “scorching grass and killing livestock”, said Reuters. The newswire wrote: “In 2015, a drought almost dried up the taps in the city; farmers say this one has been even more brutal than a decade ago.”
- NOUVELLE VEG: New guidelines published under France’s national food, nutrition and climate strategy “urged” citizens to “limit” their meat consumption, reported Euronews. The delayed strategy comes a month after the US government “upended decades of recommendations by touting consumption of red meat and full-fat dairy”, it noted.
- COURTING DISASTER: India’s top green court accepted the findings of a committee that “found no flaws” in greenlighting the Great Nicobar project that “will lead to the felling of a million trees” and translocating corals, reported Mongabay. The court found “no good ground to interfere”, despite “threats to a globally unique biodiversity hotspot” and Indigenous tribes at risk of displacement by the project, wrote Frontline.
- FISH FALLING: A new study found that fish biomass is “falling by 7.2% from as little as 0.1C of warming per decade”, noted the Guardian. While experts also pointed to the role of overfishing in marine life loss, marine ecologist and study lead author Dr Shahar Chaikin told the outlet: “Our research proves exactly what that biological cost [of warming] looks like underwater.”
- TOO HOT FOR COFFEE: According to new analysis by Climate Central, countries where coffee beans are grown “are becoming too hot to cultivate them”, reported the Guardian. The world’s top five coffee-growing countries faced “57 additional days of coffee-harming heat” annually because of climate change, it added.
Spotlight
Nature talks inch forward
This week, Carbon Brief covers the latest round of negotiations under the UN Convention on Biological Diversity (CBD), which occurred in Rome over 16-19 February.
The penultimate set of biodiversity negotiations before October’s Conference of the Parties ended in Rome last week, leaving plenty of unfinished business.
The CBD’s subsidiary body on implementation (SBI) met in the Italian capital for four days to discuss a range of issues, including biodiversity finance and reviewing progress towards the nature targets agreed under the Kunming-Montreal Global Biodiversity Framework (GBF).
However, many of the major sticking points – particularly around finance – will have to wait until later this summer, leaving some observers worried about the capacity for delegates to get through a packed agenda at COP17.
The SBI, along with the subsidiary body on scientific, technical and technological advice (SBSTTA) will both meet in Nairobi, Kenya, later this summer for a final round of talks before COP17 kicks off in Yerevan, Armenia, on 19 October.
Money talks
Finance for nature has long been a sticking point at negotiations under the CBD.
Discussions on a new fund for biodiversity derailed biodiversity talks in Cali, Colombia, in autumn 2024, requiring resumed talks a few months later.
Despite this, finance was barely on the agenda at the SBI meetings in Rome. Delegates discussed three studies on the relationship between debt sustainability and implementation of nature plans, but the more substantive talks are set to take place at the next SBI meeting in Nairobi.
Several parties “highlighted concerns with the imbalance of work” on finance between these SBI talks and the next ones, reported Earth Negotiations Bulletin (ENB).
Lim Li Ching, senior researcher at Third World Network, noted that tensions around finance permeated every aspect of the talks. She told Carbon Brief:
“If you’re talking about the gender plan of action – if there’s little or no financial resources provided to actually put it into practice and implement it, then it’s [just] paper, right? Same with the reporting requirements and obligations.”
Monitoring and reporting
Closely linked to the issue of finance is the obligations of parties to report on their progress towards the goals and targets of the GBF.
Parties do so through the submission of national reports.
Several parties at the talks pointed to a lack of timely funding for driving delays in their reporting, according to ENB.
A note released by the CBD Secretariat in December said that no parties had submitted their national reports yet; by the time of the SBI meetings, only the EU had. It further noted that just 58 parties had submitted their national biodiversity plans, which were initially meant to be published by COP16, in October 2024.
Linda Krueger, director of biodiversity and infrastructure policy at the environmental not-for-profit Nature Conservancy, told Carbon Brief that despite the sparse submissions, parties are “very focused on the national report preparation”. She added:
“Everybody wants to be able to show that we’re on the path and that there still is a pathway to getting to 2030 that’s positive and largely in the right direction.”
Watch, read, listen
NET LOSS: Nigeria’s marine life is being “threatened” by “ghost gear” – nets and other fishing equipment discarded in the ocean – said Dialogue Earth.
COMEBACK CAUSALITY: A Vox long-read looked at whether Costa Rica’s “payments for ecosystem services” programme helped the country turn a corner on deforestation.
HOMEGROWN GOALS: A Straits Times podcast discussed whether import-dependent Singapore can afford to shelve its goal to produce 30% of its food locally by 2030.
‘RUSTING’ RIVERS: The Financial Times took a closer look at a “strange new force blighting the [Arctic] landscape”: rivers turning rust-orange due to global warming.
New science
- Lakes in the Congo Basin’s peatlands are releasing carbon that is thousands of years old | Nature Geoscience
- Natural non-forest ecosystems – such as grasslands and marshlands – were converted for agriculture at four times the rate of land with tree cover between 2005 and 2020 | Proceedings of the National Academy of Sciences
- Around one-quarter of global tree-cover loss over 2001-22 was driven by cropland expansion, pastures and forest plantations for commodity production | Nature Food
In the diary
- 2-6 March: UN Food and Agriculture Organization regional conference for Latin America and Caribbean | Brasília
- 5 March: Nepal general elections
- 9-20 March: First part of the thirty-first session of the International Seabed Authority (ISA) | Kingston, Jamaica
Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz.
Please send tips and feedback to cropped@carbonbrief.org
The post Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate appeared first on Carbon Brief.
Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate
Rising temperatures across France since the mid-1970s is putting Tour de France competitors at “high risk”, according to new research.
The study, published in Scientific Reports, uses 50 years of climate data to calculate the potential heat stress that athletes have been exposed to across a dozen different locations during the world-famous cycling race.
The researchers find that both the severity and frequency of high-heat-stress events have increased across France over recent decades.
But, despite record-setting heatwaves in France, the heat-stress threshold for safe competition has rarely been breached in any particular city on the day the Tour passed through.
(This threshold was set out by cycling’s international governing body in 2024.)
However, the researchers add it is “only a question of time” until this occurs as average temperatures in France continue to rise.
The lead author of the study tells Carbon Brief that, while the race organisers have been fortunate to avoid major heat stress on race days so far, it will be “harder and harder to be lucky” as extreme heat becomes more common.
‘Iconic’
The Tour de France is one of the world’s most storied cycling races and the oldest of Europe’s three major multi-week cycling competitions, or Grand Tours.
Riders cover around 3,500 kilometres (km) of distance and gain up to nearly 55km of altitude over 21 stages, with only two or three rest days throughout the gruelling race.
The researchers selected the Tour de France because it is the “iconic bike race. It is the bike race of bike races,” says Dr Ivana Cvijanovic, a climate scientist at the French National Research Institute for Sustainable Development, who led the new work.
Heat has become a growing problem for the competition in recent years.
In 2022, Alexis Vuillermoz, a French competitor, collapsed at the finish line of the Tour’s ninth stage, leaving in an ambulance and subsequently pulling out of the race entirely.
Two years later, British cyclist Sir Mark Cavendish vomited on his bike during the first stage of the race after struggling with the 36C heat.
The Tour also makes a good case study because it is almost entirely held during the month of July and, while the route itself changes, there are many cities and stages that are repeated from year to year, Cvijanovic adds.
‘Have to be lucky’
The study focuses on the 50-year span between 1974 and 2023.
The researchers select six locations across the country that have commonly hosted the Tour, from the mountain pass of Col du Tourmalet, in the French Pyrenees, to the city of Paris – where the race finishes, along the Champs-Élysées.
These sites represent a broad range of climatic zones: Alpe d’ Huez, Bourdeaux, Col du Tourmalet, Nîmes, Paris and Toulouse.
For each location, they use meteorological reanalysis data from ERA5 and radiant temperature data from ERA5-HEAT to calculate the “wet-bulb globe temperature” (WBGT) for multiple times of day across the month of July each year.
WBGT is a heat-stress index that takes into account temperature, humidity, wind speed and direct sunlight.
Although there is “no exact scientific consensus” on the best heat-stress index to use, WBGT is “one of the rare indicators that has been originally developed based on the actual human response to heat”, Cvijanovic explains.
It is also the one that the International Cycling Union (UCI) – the world governing body for sport cycling – uses to assess risk. A WBGT of 28C or higher is classified as “high risk” by the group.
WBGT is the “gold standard” for assessing heat stress, says Dr Jessica Murfree, director of the ACCESS Research Laboratory and assistant professor at the University of North Carolina at Chapel Hill.
Murfree, who was not involved in the new study, adds that the researchers are “doing the right things by conducting their science in alignment with the business practices that are already happening”.
The researchers find that across the 50-year time period, WBGT has been increasing across the entire country – albeit, at different rates. In the north-west of the country, WBGT has increased at an average rate of 0.1C per decade, while in the southern and eastern parts of the country, it has increased by more than 0.5C per decade.
The maps below show the maximum July WBGT for each decade of the analysis (rows) and for hourly increments of the late afternoon (columns). Lower temperatures are shown in lighter greens and yellows, while higher temperatures are shown in darker reds and purples.
Six Tour de France locations analysed in the study are shown as triangles on the maps (clockwise from top): Paris, Alpe d’ Huez, Nîmes, Toulouse, Col du Tourmalet and Bordeaux.
The maps show that the maximum WBGT temperature in the afternoon has surpassed 28C over almost the entire country in the last decade. The notable exceptions to this are the mountainous regions of the Alps and the Pyrenees.
The researchers also find that most of the country has crossed the 28C WBGT threshold – which they describe as “dangerous heat levels” – on at least one July day over the past decade. However, by looking at the WBGT on the day the Tour passed through any of these six locations, they find that the threshold has rarely been breached during the race itself.
For example, the research notes that, since 1974, Paris has seen a WBGT of 28C five times at 3pm in July – but that these events have “so far” not coincided with the cycling race.
The study states that it is “fortunate” that the Tour has so far avoided the worst of the heat-stress.
Cvijanovic says the organisers and competitors have been “lucky” to date. She adds:
“It has worked really well for them so far. But as the frequency of these [extreme heat] events is increasing, it will be harder and harder to be lucky.”
Dr Madeleine Orr, an assistant professor of sport ecology at the University of Toronto who was not involved in the study, tells Carbon Brief that the paper was “really well done”, noting that its “methods are good [and its] approach was sound”. She adds:
“[The Tour has] had athletes complain about [the heat]. They’ve had athletes collapse – and still those aren’t the worst conditions. I think that that says a lot about what we consider safe. They’ve still been lucky to not see what unsafe looks like, despite [the heat] having already had impacts.”
Heat safety protocols
In 2024, the UCI set out its first-ever high temperature protocol – a set of guidelines for race organisers to assess athletes’ risk of heat stress.
The assessment places the potential risk into one of five categories based on the WBGT, ranging from very low to high risk.
The protocol then sets out suggested actions to take in the event of extreme heat, ranging from having athletes complete their warm-ups using ice vests and cold towels to increasing the number of support vehicles providing water and ice.
If the WBGT climbs above the 28C mark, the protocol suggests that organisers modify the start time of the stage, adapt the course to remove particularly hazardous sections – or even cancel the race entirely.
However, Orr notes that many other parts of the race, such as spectator comfort and equipment functioning, may have lower temperatures thresholds that are not accounted for in the protocol, but should also be considered.
Murfree points out that the study’s findings – and the heat protocol itself – are “really focused on adaptation, rather than mitigation”. While this is “to be expected”, she tells Carbon Brief:
“Moving to earlier start times or adjusting the route specifically to avoid these locations that score higher in heat stress doesn’t stop the heat stress. These aren’t climate preventative measures. That, I think, would be a much more difficult conversation to have in the research because of the Tour de France’s intimate relationship with fossil-fuel companies.”
The post Dangerous heat for Tour de France riders only a ‘question of time’ appeared first on Carbon Brief.
Dangerous heat for Tour de France riders only a ‘question of time’
Greenhouse Gases
DeBriefed 20 February 2026: EU’s ‘3C’ warning | Endangerment repeal’s impact on US emissions | ‘Tree invasion’ fuelled South America’s fires
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Preparing for 3C
NEW ALERT: The EU’s climate advisory board urged countries to prepare for 3C of global warming, reported the Guardian. The outlet quoted Maarten van Aalst, a member of the advisory board, saying that adapting to this future is a “daunting task, but, at the same time, quite a doable task”. The board recommended the creation of “climate risk assessments and investments in protective measures”.
‘INSUFFICIENT’ ACTION: EFE Verde added that the advisory board said that the EU’s adaptation efforts were so far “insufficient, fragmented and reactive” and “belated”. Climate impacts are expected to weaken the bloc’s productivity, put pressure on public budgets and increase security risks, it added.
UNDERWATER: Meanwhile, France faced “unprecedented” flooding this week, reported Le Monde. The flooding has inundated houses, streets and fields and forced the evacuation of around 2,000 people, according to the outlet. The Guardian quoted Monique Barbut, minister for the ecological transition, saying: “People who follow climate issues have been warning us for a long time that events like this will happen more often…In fact, tomorrow has arrived.”
IEA ‘erases’ climate
MISSING PRIORITY: The US has “succeeded” in removing climate change from the main priorities of the International Energy Agency (IEA) during a “tense ministerial meeting” in Paris, reported Politico. It noted that climate change is not listed among the agency’s priorities in the “chair’s summary” released at the end of the two-day summit.
US INTERVENTION: Bloomberg said the meeting marked the first time in nine years the IEA failed to release a communique setting out a unified position on issues – opting instead for the chair’s summary. This came after US energy secretary Chris Wright gave the organisation a one-year deadline to “scrap its support of goals to reduce energy emissions to net-zero” – or risk losing the US as a member, according to Reuters.
Around the world
- ISLAND OBJECTION: The US is pressuring Vanuatu to withdraw a draft resolution supporting an International Court of Justice ruling on climate change, according to Al Jazeera.
- GREENLAND HEAT: The Associated Press reported that Greenland’s capital Nuuk had its hottest January since records began 109 years ago.
- CHINA PRIORITIES: China’s Energy Administration set out its five energy priorities for 2026-2030, including developing a renewable energy plan, said International Energy Net.
- AMAZON REPRIEVE: Deforestation in the Brazilian Amazon has continued to fall into early 2026, extending a downward trend, according to the latest satellite data covered by Mongabay.
- GEZANI DESTRUCTION: Reuters reported the aftermath of the Gezani cyclone, which ripped through Madagascar last week, leaving 59 dead and more than 16,000 displaced people.
20cm
The average rise in global sea levels since 1901, according to a Carbon Brief guest post on the challenges in projecting future rises.
Latest climate research
- Wildfire smoke poses negative impacts on organisms and ecosystems, such as health impacts on air-breathing animals, changes in forests’ carbon storage and coral mortality | Global Ecology and Conservation
- As climate change warms Antarctica throughout the century, the Weddell Sea could see the growth of species such as krill and fish and remain habitable for Emperor penguins | Nature Climate Change
- About 97% of South American lakes have recorded “significant warming” over the past four decades and are expected to experience rising temperatures and more frequent heatwaves | Climatic Change
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Repealing the US’s landmark “endangerment finding”, along with actions that rely on that finding, will slow the pace of US emissions cuts, according to Rhodium Group visualised by Carbon Brief. US president Donald Trump last week formally repealed the scientific finding that underpins federal regulations on greenhouse gas emissions, although the move is likely to face legal challenges. Data from the Rhodium Group, an independent research firm, shows that US emissions will drop more slowly without climate regulations. However, even with climate regulations, emissions are expected to drop much slower under Trump than under the previous Joe Biden administration, according to the analysis.
Spotlight
How a ‘tree invasion’ helped to fuel South America’s fires
This week, Carbon Brief explores how the “invasion” of non-native tree species helped to fan the flames of forest fires in Argentina and Chile earlier this year.
Since early January, Chile and Argentina have faced large-scale and deadly wildfires, including in Patagonia, which spans both countries.
These fires have been described as “some of the most significant and damaging in the region”, according to a World Weather Attribution (WWA) analysis covered by Carbon Brief.
In both countries, the fires destroyed vast areas of native forests and grasslands, displacing thousands of people. In Chile, the fires resulted in 23 deaths.
Multiple drivers contributed to the spread of the fires, including extended periods of high temperatures, low rainfall and abundant dry vegetation.
The WWA analysis concluded that human-caused climate change made these weather conditions at least three times more likely.
According to the researchers, another contributing factor was the invasion of non-native trees in the regions where the fires occurred.
The risk of non-native forests
In Argentina, the wildfires began on 6 January and persisted until the first week of February. They hit the city of Puerto Patriada and the Los Alerces and Lago Puelo national parks, in the Chubut province, as well as nearby regions.
In these areas, more than 45,000 hectares of native forests – such as Patagonian alerce tree, myrtle, coigüe and ñire – along with scrubland and grasslands, were consumed by the flames, according to the WWA study.
In Chile, forest fires occurred from 17 to 19 January in the Biobío, Ñuble and Araucanía regions.
The fires destroyed more than 40,000 hectares of forest and more than 20,000 hectares of non-native forest plantations, including eucalyptus and Monterey pine.
Dr Javier Grosfeld, a researcher at Argentina’s National Scientific and Technical Research Council (CONICET) in northern Patagonia, told Carbon Brief that these species, introduced to Patagonia for production purposes in the late 20th century, grow quickly and are highly flammable.
Because of this, their presence played a role in helping the fires to spread more quickly and grow larger.
However, that is no reason to “demonise” them, he stressed.
Forest management
For Grosfeld, the problem in northern Patagonia, Argentina, is a significant deficit in the management of forests and forest plantations.
This management should include pruning branches from their base and controlling the spread of non-native species, he added.
A similar situation is happening in Chile, where management of pine and eucalyptus plantations is not regulated. This means there are no “firebreaks” – gaps in vegetation – in place to prevent fire spread, Dr Gabriela Azócar, a researcher at the University of Chile’s Centre for Climate and Resilience Research (CR2), told Carbon Brief.
She noted that, although Mapuche Indigenous communities in central-south Chile are knowledgeable about native species and manage their forests, their insight and participation are not recognised in the country’s fire management and prevention policies.
Grosfeld stated:
“We are seeing the transformation of the Patagonian landscape from forest to scrubland in recent years. There is a lack of preventive forestry measures, as well as prevention and evacuation plans.”
Watch, read, listen
FUTURE FURNACE: A Guardian video explored the “unbearable experience of walking in a heatwave in the future”.
THE FUN SIDE: A Channel 4 News video covered a new wave of climate comedians who are using digital platforms such as TikTok to entertain and raise awareness.
ICE SECRETS: The BBC’s Climate Question podcast explored how scientists study ice cores to understand what the climate was like in ancient times and how to use them to inform climate projections.
Coming up
- 22-27 February: Ocean Sciences Meeting, Glasgow
- 24-26 February: Methane Mitigation Europe Summit 2026, Amsterdam, Netherlands
- 25-27 February: World Sustainable Development Summit 2026, New Delhi, India
Pick of the jobs
- The Climate Reality Project, digital specialist | Salary: $60,000-$61,200. Location: Washington DC
- Intergovernmental Panel on Climate Change (IPCC), science officer in the IPCC Working Group I Technical Support Unit | Salary: Unknown. Location: Gif-sur-Yvette, France
- Energy Transition Partnership, programme management intern | Salary: Unknown. Location: Bangkok, Thailand
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 20 February 2026: EU’s ‘3C’ warning | Endangerment repeal’s impact on US emissions | ‘Tree invasion’ fuelled South America’s fires appeared first on Carbon Brief.
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