Crops that have been “altered” by scientists in a laboratory can be found growing on millions of hectares of farmland around the world.
These “genetically modified organisms” (GMOs) are planted extensively across swathes of North and South America, in particular, but remain strictly limited in many countries.
However, these stringent regulations have eased in some nations for crops altered using new, more precise “gene-editing” technologies.
Several experts tell Carbon Brief that these new technologies are not a “silver-bullet” solution for agriculture, but that they could help crops deal with extreme weather and boost nutrition in a faster, safer and cheaper way than GMOs.
In contrast, other experts, as well as environmental groups, are concerned about how these gene-edited crops will be produced, regulated and patented.
In this Q&A, Carbon Brief looks at the difference between GMOs and gene-edited foods and whether these technologies can help crops deal with climate change while boosting food security.
- What are genetically modified crops?
- Where are genetically modified and gene-edited crops grown around the world?
- What are the perceived benefits and concerns of genetically engineered foods?
- Could gene-editing and GMOs benefit food security?
- Do genetically modified crops benefit climate mitigation and adaptation?
What are genetically modified crops?
For centuries, farmers have used selective breeding techniques to prioritise growing crops with desirable traits, such as resistance to disease.
In the 1970s, scientists developed new ways to boost these traits directly by changing a plant’s genetic material.
GMOs – genetically modified organisms – are plants, animals and microorganisms whose genes have been altered with the help of technology.
Dr Jennifer Pett-Ridge is a senior researcher at the Lawrence Livermore National Laboratory and principal investigator on a soil carbon project at the Innovative Genomics Institute in Berkeley, California.
She explains that gene modification technologies take DNA from one species and insert it into another. She tells Carbon Brief:
“It might be a frog or a tomato, or something like that, that you’re importing from another organism that has a trait that you really want that will work within your organism of choice. You’re splicing that in, essentially.”
The most common traits scientists put into genetically modified crops include tolerance to weed-killing herbicides and resistance to insects and viruses. The techniques can also be used to develop plants that are better able to deal with drought, heat and other intensifying effects of climate change.
In the US in 1994 – after years of testing and experiments – a GM tomato was the world’s first genetically engineered food sold in shops, according to the country’s Food and Drug Administration (FDA).
This tomato was “genetically altered to ripen longer on the vine while remaining firm for picking and shipping”, the New York Times reported at the time.
Two years later, farmers began growing genetically engineered crops across the US. One example is “Roundup Ready” maize, cotton and other crops. These plants were developed by the chemical company Monsanto – which was bought out by Bayer in 2018 – to be more resistant to the weed-killer Roundup.
A gene that is resistant to glyphosate – the herbicide used in Roundup – was taken from a type of bacteria and inserted into these crops. This, in turn, allowed farmers to apply the herbicide to kill weeds without destroying their crops.
In more recent years, scientists have developed different ways to alter DNA. One prevailing method is Crispr/Cas9 – a gene-editing technology that can tweak genetic code without needing to introduce traits from another species. The scientists behind the discovery were awarded a Nobel Prize in 2020.
The method is akin to using a “pair of scissors to just snip a gene out and move it somewhere else” within the same plant, Pett-Ridge says, preventing the need to mix in DNA from other species, which is how GMOs are made.
For example, the technology could be used to remove a gene that makes a plant less able to deal with drought.
A 2016 study on the possibilities of Crispr for plants described the technology as relatively simple, cheap and versatile compared to other methods. So far, scientists have carried out studies on the method’s ability to alter the genetic make-up of a wide range of crops, from rice and tomatoes, to oranges and maize.
However, these trials are in the early stages of development and experts tell Carbon Brief more research is needed before they are widely commercially available.
New technologies such as Crispr are being regulated differently to other GMOs in many countries, but opinions differ on how different they truly are from older genetic-engineering techniques.
Although there is limited evidence showing that GMOs have a negative effect on human health and the environment, they remain controversial for many due to concerns over reduced biodiversity and the prevalence of crop monocultures.
Where are genetically modified and gene-edited crops grown around the world?
Genetically modified crops are widely grown in some parts of the world, such as the US and parts of South America, and are more restricted in the EU and many African countries.
In 2019, more than 190m hectares of genetically modified crops were planted around the world – an area roughly the size of Mexico – according to the International Service for the Acquisition of Agri-biotech Applications.
In 1996, around the time GM crops were being approved for commercial use in several countries, this figure stood at 1.7m hectares.
The US grows the most GM crops of any country, followed by Brazil, Argentina, Canada and India – as shown in the figure below.
Almost all soya beans, cotton and maize now planted in the US are genetically modified, often to resist pests or deal with herbicide use, according to the FDA.
Alongside feeding people, GM maize and soya beans are frequently used to feed animals. More than 95% of livestock and poultry in the US eat genetically modified crops, the FDA says.
In the EU and other parts of the world, GM crops are not widely grown. The EU’s rules require GMO foods to be labelled as such for consumers and permit individual EU countries to ban genetically modified crops, if they choose. Most EU countries do not grow GMO crops.
The EU’s GMO rules still apply in the UK. But, in 2023, the rules in England were eased to allow the development of plants that are genetically edited using modern methods such as Crispr.
Further laws are needed to allow these gene-edited plants – and, later, animals – to be sold in England. The legislation for plants is set to be brought in this summer.
Rules around whether these gene-edited plants should be treated the same as, or differently to, GMOs are still being assessed by many governments around the world.
In some countries, such as the US, they are essentially treated the same as non-GMO products. Since they do not contain “foreign” genes, they are seen as indistinguishable from conventional plants.
The EU could be moving in a similar direction with a proposal from the European Commission to loosen its stringent GMO requirements for plants that have been made using newer gene-editing technologies.
The changes would “better reflect the different risk profiles” of the way in which gene-edited plants are made compared to genetically modified ones, the commission said.
Dr Ludivine Petetin, a reader in law and expert in agri-food issues at Cardiff University, says the proposal marks a significant change from the EU’s previous attitude to genetically altered foods.
If approved, the EU would create two categories of plants that have been altered by new genomic techniques. One category of plants would be considered comparable to conventional plants and would not require any GMO labelling for consumers.
Plants that have been made using these newer techniques, but do not meet this criteria, would fall into the second category. This would require stricter assessment and mandatory labelling, similar to how GMOs are currently regulated in the EU. Petetin tells Carbon Brief:
“That’s a massive, massive difference to the precautionary principle used before, where it was all about the need to inform the public – the need to tell them whether there is [genetic modification] or not in what we are all eating.”
The “precautionary principle” approach is used to apply caution to issues that have uncertain levels of scientific evidence about a risk to environmental or human health. It is used in the EU’s directive on GMOs.
The debate around the EU’s proposal is on hold until after the European parliament elections in June.
Earlier this year, more than 1,500 scientists and 37 Nobel Prize winners signed an open letter calling on EU politicians to support gene-editing techniques and “consider the unequivocal body of scientific evidence supporting” new genomic techniques.
What are the perceived benefits and concerns of genetically engineered foods?
Proponents of GMOs highlight that they can boost crop yields and help feed the expanding global population. Critics point to human and environmental concerns.
A 2022 study found that the “right use” of GM crops could potentially “offer more benefit than harm, with its ability to alleviate food crises around the world”, based on a review of different impacts of GM crops on “sustainable agriculture” systems.
The main concerns laid out by the World Health Organization are triggering allergens, raising antibiotic resistance and spillover of GM plants into land that is growing conventional crops.
This spillover could reduce the diversity of crops being grown and lead to monocultures of plants, which can degrade soils and reduce biodiversity.
Other concerns focus on the use of pesticides and herbicides. A 2023 review study said that some areas growing herbicide-tolerant crops sometimes use more of the plant-killing chemical due to the emergence of herbicide-resistant weeds.
Nonetheless, the study found that, overall, genetically modified crops have had a positive impact on crop yields, pest and disease resistance and tolerance to stresses such as high temperatures or drought.
A 2017 study said there is evidence that GM crops can have negative environmental impacts, such as harming biodiversity. But this – and other studies – have concluded that further research is still needed on the human and environmental health risks of GM plants.
Other criticisms around GMOs and gene-edited crops centre around how they are regulated. Patenting is one of these concerns.
In the US, Brazil and other countries, GMO seeds can be patented. The global seed market, in general, is dominated by a small number of companies, such as Bayer and Corteva. The chart below shows that these two companies control 40% of the global seed market.
Petetin says that if seed patenting is permitted under the EU’s gene-editing rules, as currently proposed, it could lead to “more concentration of the seeds and the plant business”.
Experts tell Carbon Brief that the patenting of these seeds impacts farmers as they often have to re-purchase GM seeds each year from a company which has complete control over the cost.
The price of GM seeds rose by more than 700% between 2000 and 2015. A number of large seed companies have taken farmers to court for infringing on patent rights by growing GM crops without payment.
Patenting can also pose problems for small-scale seed developers, as similarities with patented crops can also lead to infringement claims. This can apply to both genetically modified and conventional crops.
Eva Corral, a GMO campaigner at Greenpeace EU, is calling for more information on the climate, health and environmental impacts of gene-edited foods and for labelling to remain in place in the EU’s rules.
She tells Carbon Brief that gene-edited crops are not a “panacea” to “miraculously solve all the problems in the world”, adding:
“We have to be really very, very cautious, which I think is something very much missing in the debate about new GMOs.”
Could gene-editing and GMOs benefit food security?
Whether through traditional breeding or by scientists in a lab, crops are often altered to make them more resistant to drought, better able to fight off disease or to improve their nutritional value.
All of these elements could be helpful for farmers around the world whose crops are being damaged by extreme weather conditions fuelled by human-caused climate change.
Disasters – such as floods, droughts and wildfires – have caused about $3.8tn worth of lost crops and livestock production over the past three decades, according to a report by the UN Food and Agriculture Organization.
Genetically modified crops can increase the amount of food grown in a certain amount of space – which is significant given that the amount of arable land around the world is declining.
Global crop production grew by more than 370m tonnes between 1996 and 2012. Genetically modified crops in the US accounted for one-seventh of this boost.
Increased crop yields and reduced losses due to extreme weather can be particularly attractive for countries hit by high levels of hunger and facing severe impacts of climate change.
Between 691 and 783 million people faced hunger in 2022, according to the UN’s 2023 report on food security and nutrition. The issue is particularly acute in Africa, where around one in five people face hunger – a “much larger” amount than the rest of the world, the report says.
Several experts tell Carbon Brief that scientists have long-hoped that Crispr’s relatively low cost and simpler technology would enable more gene-edited crop development in developing countries.
In African countries, GM and gene-edited crops could be part of the solution, but are not the only fix to problems facing agriculture, such as drought and poor crop yields, says Prof Ademola Adenle, a guest professor of sustainability science at the Technical University of Denmark. He tells Carbon Brief:
“Just like GMOs, gene-editing is not a silver-bullet solution to hunger or food security problems or climate change. But it could be part of a solution to a wide range of problems in the agricultural sector and [have] the potential to create crops that are resistant to diseases.”
Adenle, who is from Nigeria, has researched the progress in regulation and development of GM crops in different parts of Africa. GM crops are commercially grown in South Africa and a small number of other countries on the continent, such as Kenya and Nigeria.
He tells Carbon Brief that more research is needed to inform ongoing GMO and gene-editing discussions in African countries:
“Without investment in research and development programmes, Africa will be left behind…in terms of applying new technologies to solve some of the problems we have in the agricultural sector.
“Before gene-editing can be accepted in Africa, just like GMO, [countries] have to have the scientific capacity, they have to have the policy in place and, of course, they need to raise the level of awareness about the advantages and perhaps disadvantages that may be associated with the application of gene editing.”
Dr Joeva Sean Rock, an assistant professor in development studies at the University of Cambridge, has researched the politics of GM foods in Africa, particularly Ghana.
She says there is “a lot of hype” around the potential uses of gene-editing to develop crops that can “improve climate resilience and food security”. But she urges caution, telling Carbon Brief:
“An important question becomes how that hype compares with present reality…We are in a moment where there’s a real opportunity to ask not necessarily whether this technology could be a panacea, but rather if and how it might be able to benefit people at different scales and with different needs.”
A recent study found that a relatively small number of gene-editing crop projects focus on benefitting smallholder farmers in the global south. These farmers are “exceptionally vulnerable to climate change and food insecurity”, Rock says, adding:
“Farmers have diverse needs and so an important question is whether genome editing is an appropriate tool to address those needs and whether it is being used to do so.”
Do genetically modified crops benefit climate mitigation and adaptation?
There have been a lot of claims – and counter-claims – about the climate benefits of GMOs, both in terms of making crops more resistant to extreme weather and in helping plants to absorb more carbon from the atmosphere.
Dr Emma Kovak is a senior food and agriculture analyst at the Breakthrough Institute – a controversial thinktank in California that claims it “promotes technological solutions to environmental and human development challenges”.
Kovak was the lead author of a 2022 study which said that growing more GM crops, such as wheat, in the EU could lead to reduced land-use emissions in other parts of the world. The researchers estimated the extent that greenhouse gas levels would be impacted by the EU growing similar levels of genetically modified maize, soya beans, cotton, canola and sugar beet as the US.
The study claimed that this increase in EU GMOs would boost crop yields, which would allow the bloc to provide more of its own crops, Kovak tells Carbon Brief. This could lead to emissions cuts equivalent to more than 7% of the EU’s greenhouse gas emissions from agriculture, the study found. Kovak says:
“Expansion of crop production through yield increases in the EU can decrease farmland expansion in other places in the world, which means less deforestation and emissions from deforestation.”
Agriculture drives at least three-quarters of deforestation around the world, with forests cleared to raise animals and grow crops such as soya beans.
Another study published in 2018 looked at the environmental impacts of GM crops, such as maize, cotton and soya beans, on pesticide use and CO2 emissions across different countries over 1996-2016.
The study combined previous studies on fuel use and tillage systems – that is, preparing the land for crops – along with evidence on the impact of GM crop usage on these practices. It also looked at farm-level and national pesticide usage surveys.
It found that the use of GM insect-resistant and herbicide-tolerant technology reduced pesticide spraying by 8%. This, as a result, reduced the environmental impacts of herbicide and insecticide use.
It further led to cuts in fuel use and tillage changes, resulting in a “significant reduction” in emissions from areas growing GM crops. Combining figures from reduced fuel use and increased soil carbon storage, the researchers said the emissions reduction would be equivalent to taking almost 17m cars off the road for one year.
A 2011 review study found that GM crops could reduce the impacts of agriculture on biodiversity in a number of ways, such as by reducing insecticide use and boosting crop yields to ease the pressure to transform more land to grow crops.
A 2021 study found a correlation between GM crop growth and use of the herbicide glyphosate with an increase in soil carbon sequestration in a province of Canada. However, herbicide use decreased soil biodiversity in banana fields in Martinique, a Caribbean island, a different study found.
When it comes to gene-edited plants, experts tell Carbon Brief that more research is needed to determine the possible climate benefits or negative impacts.
Studies on gene-edited crops remain in the early stages of development.
In terms of boosting carbon sequestration through soils, whether it is through gene-editing or conventional breeding, Pett-Ridge says that definitive results are still some distance away. She tells Carbon Brief:
“There is a lot of hype…there are folks out there saying that this can solve everything or we can fix our climate issues with soils. I would push back on that, while still saying it’s a significant opportunity.”
Targeting certain traits through gene-editing will “take some time before we can really assess whether those have a net benefit on the amount of carbon put in soil”, she adds:
“As much as I’m an optimist and excited about it… I don’t know anyone who has got traits focused on carbon capture really being applied even in a field trial.”
Petetin believes gene-editing may “provide some answers” to help the agriculture sector deal with extreme weather and other issues, but adds:
“They’re not the only answers to all the issues agriculture is facing with biodiversity and climate change emergencies. Putting all your eggs in this one basket is not the solution.”
The post Q&A: The evolving debate about using genetically modified crops in a warming world appeared first on Carbon Brief.
Q&A: The evolving debate about using genetically modified crops in a warming world
Four Ugandan farmers filed a case with London’s High Court on Tuesday, aiming to stop the East African Crude Oil Pipeline (EACOP) from starting to operate by asking the court to apply Uganda’s laws against the project’s UK-registered company.
The controversial 1,443-kilometre (897-mile) pipeline, majority-owned by French energy company TotalEnergies, aims to carry crude from Ugandan fields for export through neighbouring Tanzania. About 80% has been built so far, according to its developers.
The pipeline’s first oil exports are expected as soon as October, according to its developers, and the campaign group Avaaz, which is backing the farmers’ crowdfunded lawsuit, called it “one final chance to stop one of the worst oil pipelines on the planet”.
The claim, filed by London law firm Leigh Day, argues that EACOP Ltd’s role in developing and operating the pipeline breaches Ugandan laws that protect citizens’ right to a clean and healthy environment.
-
Ugandan farmers use British court to try to stop East Africa oil pipeline
The farmers and their lawyers will argue that a UK-based entity linked to the East African Crude Oil Pipeline has breached Ugandan law and construction should halt -
French court rules Total must revise climate plan to account for all emissions
Oil and gas giant TotalEnergies has been given six months by a court to publish a more robust climate plan -
Uganda cites contentious IEA fossil fuel scenario backed by Trump administration
Critics of the African nation’s oil ambitions say referencing the International Energy Agency’s most pessimistic scenario for climate action is a risky policy
One of the claimants, Racheal Tugume, told a press conference she had been displaced from her land due to the pipeline’s construction, which she said had damaged local rivers, wildlife and ecosystems that communities depend on for their livelihoods just as erratic weather linked to climate change takes an increasing toll.
“I am very happy that there are people in countries like the UK who are listening to us, who are behind us and who have come to support us,” Tugume said, adding that she hoped the case would bring justice to communities affected by the pipeline.
Ugandan law in UK court
While the pipeline is a joint venture led by TotalEnergies, with smaller stakes owned by Ugandan, Tanzanian and Chinese national oil firms, it is operated by EACOP Ltd, a company registered to an office in London’s Canary Wharf financial district.
EACOP Ltd did not respond to a request for comment.
The claim appears to be the first attempt to have Uganda’s climate and environmental protections enforced in a foreign court, partly reflecting concerns over whether cases challenging the multibillion-dollar pipeline would get a fair trial in Uganda.
Ugandans living near new oil pipeline let down by compensation programmes
Concerns about access to a fair hearing are among the issues the court will consider when deciding if it should take on the case, said Matthew Renshaw, partner at Leigh Day.
Renshaw said that precedents including the Nigerian oil pollution case against Shell have shown that claims against British-registered companies for harms overseas can be successfully fought in UK courts.
“We are proud to represent the four brave principled individuals,” Renshaw said.
Constitutional protections
The pipeline project has already been subject to repeated lawsuits in several countries, none of which have succeeded. A climate lawsuit filed in Uganda more than a decade ago by a group of young people has yet to conclude. Another at the East African Court of Justice, brought by campaign groups against Uganda and Tanzania, was rejected on procedural grounds last November.
A separate ongoing lawsuit in TotalEnergies’ home country of France – a refiled version of an earlier failed claim – cannot stop EACOP going ahead, but it does seek damages from TotalEnergies for affected communities.
With the newly launched case, Leigh Day’s legal adviser Marc Willers said the claim draws on specific Ugandan laws in a bid to stop EACOP’s operations.
Uganda may see lower oil revenues than expected as costs rise and demand falls
These include the Ugandan constitution, a 2019 environmental law and the National Climate Change Act 2021, which gives Ugandans the right to bring a case before a court in circumstances where anyone or any entity threatens the country’s ability to mitigate climate change.
Stopping a “carbon bomb”
The pipeline, which will link Uganda’s Lake Albert oil fields to Africa’s east coast in Tanzania, has already displaced thousands of people and cuts through the Lake Victoria basin, one of East Africa’s major freshwater systems and a critical water source for around 40 million people.
According to the BankTrack non-profit, when the pipeline is at peak production, it will carry 216,000 barrels of crude oil per day and release over 33 million tonnes of carbon emissions each year. Over its full lifetime of 25 years, it is estimated to release about 379 million tonnes of greenhouse gas emissions across its value chain including construction, refining and product use.
A May 2026 report from Earth Insight also warns that the pipeline and related infrastructure could affect 158 wetlands in Uganda, 11 rivers, 44 protected areas and seven key biodiversity areas while disrupting about 2,000 square km of protected wildlife habitats.
This is why the primary focus of the UK court case is to stop the operation of the pipeline in its tracks, Leigh Day’s Willers said, calling it a “carbon bomb” that would worsen the world’s climate crisis.
Long wait for first hearing
While the purpose of the case is to stop the pipeline from launching operations, Renshaw said it could take about 12 months before the case gets a first hearing and about 18 months before it goes to trial.
Billions unlocked as Green Climate Fund agrees to spend more and save less
The farmers are, however, seeking an injunction to stop EACOP Ltd from proceeding with operations. In the event that shipments begin, the lawsuit will still seek to stop the pipeline from then on, Renshaw said.
“We will be doing what we can to expedite matters but it is possible that EACOP will have started operating the pipeline before the claim is heard. If that is the case, the claim would intend to halt operations from that point. For example, the pipeline may operate for just one year rather than 30-plus, resulting in far less harm,” he said.
The post Ugandan farmers launch UK court case against East African oil pipeline appeared first on Climate Home News.
Ugandan farmers launch UK court case against East African oil pipeline
Climate Change
Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole
Welcome to Cited, your essential guide to new climate research.
In the news
‘HEAT ALERT’: At least 25 people died as a “heat dome” smothered the eastern half of the US, reported the Guardian, with more than 20 states under “stifling temperatures more than 100F (38C)”. More than 140 million people were under heat alerts, the outlet said, with dead bodies found in “homes with no air conditioning, outside their residences, on the street and in parked cars”. Analysis by World Weather Attribution (WWA) found that the combined heat and humidity would have been “virtually impossible” without human-caused warming, reported the New York Times.
‘MORTALITY WILL RISE FURTHER’: Meanwhile, extreme heat continued to hit Europe, with Le Monde reporting on temperatures of 40C in France, Portugal and Spain again this past weekend, alongside “devastating” wildfires. Public Health France doubled its preliminary estimate of the “excess deaths” from the extreme heat in late June, from 1,000 to more than 2,000, according to the Guardian. The higher figure was still “probably an underestimate”, the agency said. Analysis published by Carbon Brief put the figure at 2,700 heat-related deaths. A WWA attribution study, covered by Carbon Brief, found that Europe’s June heatwave would have been “virtually impossible” even 50 years ago.
‘BOOST TO GLOBAL TEMPERATURES’: The UN World Meteorological Organization (WMO) “raised its forecast for the rapid emergence of a strong El Niño in the coming months, warning that the phenomenon is likely to drive global temperatures higher”, reported Reuters. A WMO scientist told the newswire that “El Niño conditions have emerged in the equatorial Pacific and there is a remarkable agreement between forecast models that this will be a strong El Niño”.
Research picks
Extremes
- The annual season when “intense” tropical cyclones occur has lengthened by 10-14 days per decade across the world since the 1980s | Nature Communications
- There is an “increasing” and “overlooked” global threat from glacial outburst floods from small lakes | Nature Sustainability
- Female smallholder farmers in sub-Saharan Africa experience crops losses 2-2.5 times greater than male smallholders in periods of extreme heat | Nature Sustainability
Policy
- The summaries for policymakers in Intergovernmental Panel on Climate Change (IPCC) mitigation reports over 2001-22 “have not yet become more solution-oriented while abiding by their policy-neutrality principle” | npj Climate Action
- Two-thirds of countries address inequality in their national pledges under the Paris Agreement – particularly in “countries with lower levels of human development and greater income inequality” | Climate and Development
- To “future proof” the Paris Agreement’s “well-below 2C” limit, it should be interpreted as a median “peak warming” of 1.6-1.8C, rather than a 66-90% chance of staying below 2C | Nature Climate Change
Land sink
- From 2001 to 2015, northern Eurasia absorbed about 0.47bn tonnes of carbon each year – around one-third of the total global land carbon sink | Global Biogeochemical Cycles
- Model simulations of potential land-use carbon emissions out to 2100 show that “deforestation and forest regrowth dominate variability” of emissions, with policy timing and ambition “exerting strong control” | Nature Communications
- Tropical forests are facing an increase in areas that exceed critical temperatures where their “photosynthetic system breaks down” | Proceedings of the National Academy of Sciences
Captured
On 21 June, global average sea surface temperature (SST) reached a record high for the day of the year, according to the Copernicus Climate Change Service (C3S). Daily SST for the global ocean, excluding polar regions, reached 20.86C on 21 June, exceeding the 20.83C reached on the same day in both 2023 and 2024, the C3S said. Global SST has remained at record levels for every day since. The conditions “could indicate the beginning of a new phase, leading, once more, to uncharted territory”, said C3S director Carlo Buontempo.
56 hours and 30 hours
The amount of time that the average lifespan of tropical cyclones in the north-east and north-west Pacific has shortened, respectively, over 1982-2024, according to a study in npj Climate and Atmospheric Science. This shorter lifespan “compresses the time available for weather forecasting and disaster preparedness”, the authors said.
Spotlight
The ozone hole and climate change
As a new “thought experiment” asks whether the hole in the ozone layer could, theoretically, have been identified decades before it was discovered, Carbon Brief explores the interactions between climate change and the ozone hole.
It is now more than 40 years since the discovery of the hole in the ozone layer over Antarctica, detailed in the journal Nature in 1985.
A study more than a decade earlier had predicted that chlorine-based substances – such as chlorofluorocarbons (CFCs) – could lead to the destruction of ozone in the stratosphere.
So, in theory, how early could the ozone hole have been detected?
New research, published in the Proceedings of the National Academy of Sciences, explored this very question.
Study co-author Prof Susan Solomon from the Massachusetts Institute of Technology is a leading atmospheric scientist. In the late 1980s, Solomon and colleagues identified the mechanism behind how CFCs were causing ozone depletion.
The new study is a “thought experiment”, Solomon told Carbon Brief, asking when scientists could have discovered the ozone hole had they had access to modern satellite observations.
“We found that depletion could have been detected as early as 1957 in the tropical upper stratosphere, where natural variability is especially small,” explained Solomon.
This would have been before the use of CFCs became widespread, Solomon added. Instead, early ozone depletion was caused by carbon tetrachloride, a chemical used as a cleaning agent, as well as in fire extinguishers and for producing refrigerants.
For many decades, the ozone hole and global warming have often been confused by the public and the media, Solomon explained:
“It’s common to imagine that because ozone is so important at shielding us from the UV [ultraviolet] light that causes skin cancer, then having less ozone must mean the Earth would warm up.”
For example, in a 1995 editorial, the Los Angeles Times congratulated the Nobel prize-winning chemists who identified the threat of CFCs to the ozone layer. The newspaper noted that these processes “threaten calamitous global warming by damaging the Earth’s protective layer of ozone”.
However, said Solomon, “the Earth is warmed much more by visible light – UV doesn’t really contribute, so ozone depletion doesn’t cause significant warming”.
Regional impacts
The depletion of ozone actually has a very small cooling effect at the Earth’s surface. But this is more than outweighed by the warming impact of CFCs and other ozone-depleting substances.
This warming impact means that efforts to reverse ozone depletion have had a beneficial impact on the climate.
The Montreal Protocol, a 1987 international agreement to phase out CFCs, “has played – and is playing – a very substantial role in safeguarding climate too”, said Solomon:
“It turns out that the CFCs and their replacement gases HCFCs [hydrochlorofluorocarbons] are strong greenhouse gases, so phasing out their production has not only avoided a lot of ozone depletion that would otherwise have occurred, it also had a big influence on global warming.”
HCFCs were considered as “transitional substitutes” for CFCs – they still damaged ozone, but to a lesser extent – until ozone-safe alternatives were commercially available.
Hydrofluorocarbons (HFCs), which are not ozone depleting, began to be used widely in the 1990s. However, HFCs are also potent greenhouse gases. HFCs and similar replacements are now being phased out under the 2016 Kigali Amendment to the Montreal Protocol.
While the ozone hole itself has only a very small impact on global temperatures, it does have a clear impact on the regional climate over Antarctica.
Prof David Thompson from Colorado State University, working with colleagues including Solomon, has published research demonstrating that “changes in southern-hemisphere winds linked to the stratospheric ozone losses extend all the way down to the ground in some seasons”, explained Solomon.
This has “reduc[ed] warming that would have occurred in interior Antarctica and enhanc[ed] warming in the Antarctic Peninsula region”, she said.
The knock-on impacts include “wind changes [that] actually extend beyond Antarctica to the mid-latitudes of the southern hemisphere, where they even affect rainfall”, she added.
Preprints to watch
Carbon Brief’s pick of new papers under review
- The drying impact over Africa from using stratospheric aerosol injections to stabilise global temperatures would only be minimised “when combined with a strong decarbonisation effort” | Earth System Dynamics
- The El Niño-Southern Oscillation and Indian Ocean Dipole could “shape” the playing conditions at the Rugby World Cup 2027 in Australia | Journal of Southern Hemisphere Earth Systems Science
- A “strong” weakening of the Atlantic Meridional Overturning Circulation (AMOC) would “profoundly alter the climate-carbon cycle system”, underscoring the “importance of explicitly accounting for AMOC risks in long-term climate assessments” | Earth System Dynamics
Noticeboard
- 6 July-25 September: Registration open for experts to review the first-order draft of the Intergovernmental Panel on Climate Change’s Working Group I report
- 7-15 July: UN High-level Political Forum on Sustainable Development, New York
- 19 July: Application deadline for a postdoctoral scholar in transdisciplinary climate research at Penn State University, US | Salary: unknown
- 22 July: Application deadline for PhD project on “climate change impacts on the Antarctic coastal ocean carbon sink” at the University of East Anglia, UK
- 26 July: Application deadline for PhD projects on “AI for land-atmosphere feedbacks during hydroclimatic extremes” at the Helmholtz School for Integrated Data Science in Environmental & Life Sciences, Germany
- 29 July: Application deadline for an assistant professor in Earth and environmental geosciences (palaeoclimatology) at Colgate University, US | Salary: $97,500-101,500
- 31 July: Application deadline for PhD project on Arctic Ocean methane oxidation at Stockholm University, Sweden
Cited is researched and written by Cecilia Keating, Robert McSweeney, Ayesha Tandon, Daisy Dunne and Dr Giuliana Viglione.
Please send tips, feedback and upcoming climate research to cited@carbonbrief.org
This is an online version of Carbon Brief’s fortnightly Cited email newsletter. Subscribe for free here.
The post Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole appeared first on Carbon Brief.
Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole
In June 2026, a record-breaking heatwave swept across Europe, with France among the first and hardest hit countries.
In a new analysis, we estimate that the extreme conditions caused more than 2,700 heat-related deaths in France.
We also show how France’s extreme temperatures in June exceeded projections from climate models.
Our findings illustrate the human toll of extreme weather as the world warms.
We also highlight the challenges in projecting the magnitude of future heatwaves and their impacts on people.
Outpacing projections
For most of this century, Europe has seen summer heat extremes that outpace projections from climate models.
Several different factors likely explain this trend, including reductions in planet-cooling aerosols as nations have cleaned up their air pollution, as well as changes in atmospheric circulation patterns, which models struggle to represent.
In June 2026, daily high temperatures averaged across France reached 36.9C, shattering the previous June record set in 2022 by 2.4C.
[For more on the impacts and coverage of Europe’s June heatwave, see Carbon Brief’s explainer.]
The rise in observed temperatures in France has outpaced projections made by climate models, with June maximum temperatures more in line with what was expected for the 2070s.
This is illustrated in the figure below, which shows how France’s average maximum daily high temperature for June recorded in 2026 (black line) compares to climate model projections (blue and orange lines).
Counting the death toll of climate change
The downstream impacts of these extreme temperatures are lethal.
Scientists are able to estimate the death toll of high temperatures in many locations, depending on the availability of mortality and climate data.
There are several ways to do this.
One option is to examine death certificates to see which deaths have been directly recorded by physicians as related to heat. However, there is strong evidence that this method significantly undercounts heat-related deaths, as most death certificates do not consider environmental factors such as heat when diagnosing the cause of death.
Alternatively, it is possible to calculate the rate of total (“all-cause”) mortality in a given time period relative to previous time periods – for example, by comparing the total number of deaths in June 2026 compared to the average of previous Junes. This “excess deaths” figure can be used as an estimate of the deaths from a heat wave.
Using this approach, Public Health France attributed around 2,000 deaths in France to the extreme heat in the week of 22-28 June.
Finally, scientists can use long-term data on overall mortality and correlate changes in mortality with changes in temperature to understand the statistical relationship between the two.
Research published in Proceedings of the National Academy of Sciences in 2025 that used this third approach found that mortality rates in France increase rapidly in cold or hot conditions as daily maximum temperatures depart further from approximately 20C.
This pattern of a U-shaped response of mortality to temperature – shown in the figure below – is very consistent across time periods and regions around the world.
To calculate the death toll of the June 2026 heatwave in France, we compared observed temperatures over 12-29 June to their baseline average over 1980-2025.
The difference between these two temperatures helps us understand how many more people died than they would have in the absence of such extreme conditions.
Over 12-29 June, we found that France has experienced around 2,700 heat-related deaths above the average baseline. Day-to-day heat-related mortality rates rose from less than 100 to almost 300 on the hottest days of 24 and 25 June.
This is shown in the graph below, which illustrates the cumulative total heat-related deaths seen in France over the two-and-a-half week period. The inset shows how heat-related deaths fluctuated on a day-to-day basis during this time.
Recent analysis by World Weather Attribution has already shown that human-caused climate change increased the frequency and intensity of the June heat wave across Europe.
Meanwhile, previous research has shown there is substantial evidence that heat-related mortality in Europe has already been elevated by greenhouse gas emissions.
As a result, we can be confident that at least some of the more than 2,700 deaths already seen in France are directly due to the burning of fossil fuels.
Calculating climate risk
In April, the UN-led body responsible for coordinating the work of climate modelling centres – the Coupled Modelling Intercomparison Project (CMIP) – unveiled a set of seven new emissions scenarios.
These are designed to replace the previous scenarios that have been used by scientists to understand how the climate might change in the future. They will feed into the upcoming seven assessment report (AR7) of the Intergovernmental Panel on Climate Change (IPCC).
The range of future emissions in the new CMIP scenarios is smaller, with scenarios of very high or very low emissions no longer on the table.
The retirement of the very-high emissions scenario – known as “RCP8.5” – led to certain commentators in the media and in politics, including US president Donald Trump, arguing that the risks of climate change had been “overstated”.
[For more on false and misleading claims around the new emissions scenarios, see Carbon Brief’s factcheck.]
Our analysis of June’s heat-related deaths in France suggests that, even if the most severe emissions pathways are no longer needed, climate impacts are taking a heavy toll on society.
Moreover, the temperatures seen in France show that climate models continue to underpredict the magnitude of heatwaves for a particular level of global warming.
This is because greenhouse gas emissions are only a first step in estimating the impacts of climate change.
The second step is converting emissions to changes in the climate at both the global and local levels – or hazards. This includes heatwaves, flash floods and droughts.
The third step is to determine how changes in the hazards will affect local populations. This can be determined by calculating people’s exposure and vulnerability to hazards.
Substantial uncertainty persists at every stage of this sequence.
For example, scientists do not know exactly how the global climate will react to ever-rising greenhouse gas emissions – nor the extent to which global temperature increases will drive local climate hazards. We also do not know how climate change at a local level impacts human health outcomes.
Managing the future of heat risk
Almost all heat-related deaths are preventable.
Adaptation options, such as air conditioning, heat action plans and social support for isolated people, will be crucial as the climate moves away from the typical conditions that people are used to.
Our previous research showed that France made a lot of progress reducing heat-related mortality after the deadly 2003 summer heatwave by taking many of these actions.
Adaptation can reduce deaths, but it cannot eliminate the risk created by continued warming.
Without a move away from fossil fuels, future heatwaves will keep testing the limits of public health systems and more people will die.
The post Guest post: France’s June heatwave caused more than 2,700 heat-related deaths appeared first on Carbon Brief.
Guest post: France’s June heatwave caused more than 2,700 heat-related deaths
-
Climate Change11 months ago
Guest post: Why China is still building new coal – and when it might stop
-
Greenhouse Gases11 months ago
Guest post: Why China is still building new coal – and when it might stop
-
Greenhouse Gases2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Climate Change2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Renewable Energy9 months agoSending Progressive Philanthropist George Soros to Prison?
-
Climate Change2 years ago
Bill Discounting Climate Change in Florida’s Energy Policy Awaits DeSantis’ Approval
-
Carbon Footprint2 years agoUS SEC’s Climate Disclosure Rules Spur Renewed Interest in Carbon Credits
-
Greenhouse Gases12 months ago
嘉宾来稿：探究火山喷发如何影响气候预测