Warming driven by deforestation caused an extra 28,000 heat-related deaths per year across Africa, South America and Asia over 2001-20, new research finds.
The study, published in Nature Climate Change, is the first to look at human health impacts of warming caused specifically by tropical deforestation, as opposed to the burning of fossil fuels, its lead author tells Carbon Brief.
The authors find that deforestation alone drove, on average, 0.45C of warming in the tropics over 2001-20, accounting for 64% of the total warming in regions with tropical forest loss.
They also find that tropical deforestation over 2001-20 exposed 345 million people to “local warming”, in addition to the warming they were already facing due to global warming.
Six out of every 100,000 people living in deforested areas died as a result of deforestation-induced warming during this time, they warn.
This number is higher in south-east Asia, with Vietnam setting a record of, on average, 29 deaths per 100,000 people.
A researcher who was not involved with the study tells Carbon Brief that the “sobering” paper “reframes tropical deforestation as not only a carbon emissions and ecological issue, but also a critical public health concern”.
Tropical deforestation
Tropical forests, mainly distributed across South America, Africa and Asia, account for 45% of global forest cover.
These regions are well-known for their high biodiversity and the crucial ecosystem services that they provide, such as carbon storage.
However, tropical forest loss is on the rise.
A record 6.7m hectares of previously intact tropical forest was lost last year, mainly due to fires and land clearing for agriculture. As the planet warms, worsening heat and drought extremes are also causing trees to become less resilient to change, resulting in forest degradation.
The new study uses data from the Global Land Analysis and Discovery laboratory at the University of Maryland to assess how tropical forest cover has changed year on year. The authors find that over 2001-20, a total of 1.6m square kilometres (160m hectares) of tropical forest was lost globally. This is shown on the map below, where blue indicates high forest loss and yellow indicates low loss.
The authors find the largest forest loss was in central and South America, but also highlight “extensive” loss in south-east Asia and tropical Africa.
Forest warming
Tropical deforestation has a wide range of negative consequences, including decreasing biodiversity, releasing carbon into the atmosphere and threatening the safety of Indigenous communities.
Loss of tree cover can also affect local temperatures by influencing the water cycle.
Water is constantly moving from the surface of the land into the atmosphere through a process called evapotranspiration. Plants play a crucial part in this process by moving water from the soil up through their roots and into their leaves, where it evaporates, cooling the air above. When trees are cut down, this cooling effect is reduced.
The authors use data of land surface temperatures from the NASA MODIS satellite to map warming in tropical regions over 2001-20. These results are shown in the map below, where red indicates warming and blue indicates cooling.
The authors find that between 2001-03 and 2018-20, surface temperatures increased by 0.34C in tropical central and South America, 0.1C in tropical Africa and 0.72C in south-east Asia. They add that “areas of forest loss coincide with areas of strong positive change in temperature across many regions of the tropics”.
By comparing their deforestation and surface warming maps, the authors find that deforested regions of the tropics saw an average of 0.7C warming over 2001-20, while areas that “maintained forest cover” saw an increase of only 0.2C.
By comparing the change in temperature in deforested regions with that in neighbouring locations without forest loss, they find that deforestation alone caused 0.45C of warming in the tropics over 2001-20 – accounting for 64% of total warming experienced over those regions.
Heat exposure
High temperatures can be deadly.
During periods of extreme heat, people can suffer from heat stroke and exhaustion – and even die. Those with underlying health conditions are at higher risk of fatal complications.
The authors use data from Oak Ridge National Laboratory’s LandScan to map where people live in the tropics. They estimate that 425 million people live in regions that were exposed to tropical deforestation over 2001-20, and just over three-quarters of them were exposed to warming as a result of the loss of forest cover.
Finally, the authors estimated “heat-related excess mortality” due to nearby tropical deforestation.
Using data from the 2019 Global Burden of Disease study, they determine the number of “non-accidental” deaths in each deforested tropical area. This excludes deaths from “external” causes, such as accidents and suicides, but includes “internal” causes, such as disease.
The researchers then used previously published “temperature-mortality” relationships for different countries. These relationships show the link between temperature and excess mortality rate, indicating the percentage increase in mortality for every degree of warming.
These relationships vary between countries, as people in hotter regions are generally better adapted to extreme heat.
By combining the data on local warming due to deforestation, temperature-mortality relationships and the non-accidental mortality data, the authors calculated how many non-accidental deaths would have been expected in deforested regions if they had not warmed due to the loss of forest cover.
By comparing the real and counterfactual mortality rates, the authors were able to calculate the total mortality burden due to tropical deforestation-induced warming.
Overall, the authors find that tropical deforestation drove an additional 28,300 deaths every year over 2001-20, accounting for 39% of the total heat-related mortality from global climate change and deforestation combined over locations of forest loss.
The study finds that, on average, six out of every 100,000 people living in deforested areas died as a result of deforestation-induced warming. However, these numbers vary by country.
The chart below shows the average annual deaths due to deforestation-induced heat per 100,000 people living in areas of forest loss.
Dr Carly Reddington is a research fellow at the University of Leeds and lead author of the study. She tells Carbon Brief that it is the “first study to look at human health impacts of tropical deforestation-induced warming”.
Dr Nicholas Wolff, a climate change scientist at the Nature Conservancy who was not involved with the study, tells Carbon Brief that the paper is “sobering”. He adds that it “reframes tropical deforestation as not only a carbon emissions and ecological issue, but also a critical public health concern”.
Data-scarce
The authors note that there are no country-specific heat vulnerability indices available for African countries. To develop their data for African countries, they used the average heat vulnerability index for South America.
Reddington tells Carbon Brief that Africa is the most “uncertain region” in the study and tells Carbon Brief that “more data is really crucial” to develop more accurate estimates.
Wolff tells Carbon Brief that extrapolating heat-mortality relationships “from data-rich regions to data-poor ones” is a “common practice in global-scale climate-health research”.
He praises the overall methodology as “innovative, transparent and scientifically sound, with appropriate caveats”.
Dr Luke Parsons, a climate modelling scientist at the Nature Conservancy, tells Carbon Brief that the conclusions are “robust”. However, he notes some “methodological issues” with the paper, such as the fact that all results are modelled, rather than measured.
He tells Carbon Brief that future work could assess “near-surface air temperature and humidity changes associated with deforestation, as well as study regional air temperature changes beyond deforested areas”.
While the new study focuses on warming within one square kilometre of forest loss, Reddington tells Carbon Brief that “deforestation is associated with warming up to 100km away”.
Furthermore, the study notes that the increase in deaths due to excess heat is likely to affect the most vulnerable members of society the most. It says:
“Vulnerable populations, particularly traditional and Indigenous communities, often live near deforested areas and face limited access to resources and infrastructure needed to cope with the combination of rising temperatures and environmental changes caused by deforestation and climate change.”
Wolff also stresses this disparity, adding that “many of these communities depend on forest clearing for agriculture, income and survival, and are forced to make difficult choices between short-term economic needs and long-term health and environmental stability”.
The authors also note that deforestation can drive a range of other interacting health problems, which were not considered in this study. For example, deforestation is linked to a rise in zoonotic diseases, such as malaria.
Dr Vikki Thompson, a climate scientist at the Royal Netherlands Meteorological Institute who was not involved in the study, says that the findings of the paper are “relevant to everyone”. She continues:
“We can reduce impacts of extreme heat by planting more trees and reducing deforestation everywhere, on both local and international scales.”
The post Warming due to tropical deforestation linked to 28,000 ‘excess’ deaths per year appeared first on Carbon Brief.
Warming due to tropical deforestation linked to 28,000 ‘excess’ deaths per year
June Rubis is a steering group committee member for the Cali Fund, from Sarawak in Malaysian Borneo.
At COP16 in Cali, governments made a significant commitment: at least half of the funding from the new Cali Fund should support the self-identified needs of Indigenous Peoples and local communities, including women and youth. It was a watershed moment for multilateral benefit-sharing.
The challenge now is to translate that commitment into access arrangements that recognise the different institutions, priorities and decision-making processes of Indigenous Peoples and local communities.
For generations, biodiversity and traditional Indigenous knowledge have provided significant value to companies who depend on nature’s genetic diversity to discover new drugs that fight diseases, create products that improve health, and grow crops resilient to extreme heat and flooding events. While some compounds are sampled directly from the source country, increasingly the digital blueprints are held in online public databases which are freely accessible to use for innovation and research.
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The Cali Fund was established at COP16 to encourage commercial users of Digital Sequence Information, or DSI, to share benefits arising from its use. Estimates suggest it could generate over $3.5 billion a year – a stark contrast to the modest $10,656 currently committed to the fund from just five SMEs, underlining how much progress must be made at COP17 over the next two weeks.
The COP16 decision that set up the fund offers two routes for money to reach Indigenous Peoples and local communities: through government authorities, and through direct payments to institutions identified by Indigenous Peoples and local communities themselves.
Varied ways of organising
Indigenous Peoples and local communities organise through a wide range of institutions. Some have national or regional organisations experienced in managing international grants. Others work through territorial organisations, customary institutions, community associations, cooperatives or networks. Some have professional finance teams and audited accounts; others have extensive experience governing territories, collective resources or conservation work without having been organised around international funding requirements.
For direct access, some questions are already apparent. Which institutions should be able to receive funds? How should they be identified? What fiduciary standards should apply? How should safeguards and accountability work where institutional capacities differ? What support may be needed where institutions have strong community mandates but less experience with international finance?
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If access is designed mainly around institutions that already meet the expectations of large international finance mechanisms, early funding will tend to favour those already familiar to funders. They will gain further experience and become better positioned for future funding, while institutions with less administrative capacity may remain outside the system despite strong community mandates and long histories of stewardship.
These first decisions matter most, because they set the terms for everyone who follows.
The role of intermediaries requires care. Some Indigenous organisations may want a fiscal host to hold and manage funds on their behalf. Communities may choose to work through an NGO they trust. Government-facilitated arrangements may work well in particular national contexts.
What matters is the function an intermediary performs and the authority that comes with it. Providing administrative support is different from deciding which Indigenous organisations qualify, which priorities can receive support, or how success will be assessed. Direct access means communities keep that decision-making authority.
Decision-making power
The COP16 decision refers to institutions that Indigenous Peoples and local communities identify. But authority among Indigenous Peoples does not sit in one kind of body. It may sit with territorial organisations, customary institutions, community associations or combinations of these. Legal recognition and customary authority do not always align neatly.
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An important feature of the Cali Fund’s governance is that Indigenous Peoples and local communities participate as full members of the Steering Committee, rather than as observers. Seven Indigenous Peoples and local community representatives, one from each of the seven socio-cultural regions, participate in consensus-based decision-making alongside representatives of governments and UN entities. Six additional representatives from civil society, scientific institutions and the private sector participate as observers.
That representation carries responsibility. Institutional legitimacy, access and representation take different forms across the seven socio-cultural regions. Indigenous Peoples and local communities members therefore have an important role in bringing those differences into the Fund’s governance and in ensuring that arrangements developed for one context do not become the assumed model for everyone else.
Safeguards and clear responsibilities
COP17 can establish the core principles and direction, while allowing operational pathways to develop in ways that respond to different regional contexts. The decisions countries take in Yerevan will shape how that flexibility is realised in practice.
The choices made around access will influence which institutions are able to participate, which routes become established and which forms of authority are recognised within the funding architecture. The aim should be an architecture with enough structure to maintain confidence while allowing for different forms of Indigenous and community governance.
A credible direct-access pathway will need safeguards, financial oversight and clear responsibilities. This would give the 50% commitment a stronger institutional foundation.
The Cali Fund’s importance will ultimately depend not only on how much funding reaches Indigenous Peoples and local communities, but on whether they are able to determine how the money is accessed, governed and used. This requires access pathways that recognise their institutions, priorities and decision-making processes, rather than requiring them to conform to a single predetermined model.
The post COP17 must settle who decides how Cali Fund money is disbursed appeared first on Climate Home News.
COP17 must settle who decides how Cali Fund money is disbursed
The UK government has approved extraction at the Jackdaw gas field in the North Sea, despite acknowledging that this decision could make it harder for Britain to convince other countries to move away from fossil fuel production.
UK energy secretary Miatta Fahnbulleh approved the drilling on Wednesday after months of high-profile debate, fuelled in part by interventions from US President Donald Trump. She argued that the project would boost energy security in the wake of the Middle East fossil fuel crisis, protect hundreds of jobs and add £2.9 billion ($3.88bn) to the UK economy.
She said Jackdaw’s gas would be cleaner than imported gas and would not prevent the UK from meeting its legally-binding carbon targets and its goal of net zero by 2050. As the field is already licensed, she said extraction was consistent with the Labour Party’s 2024 manifesto promise not to issue any new oil and gas licenses.
The same morning, the government announced a new Energy Wealth Fund to reinvest oil and gas revenues in the climate transition. It will start with £2 billion ($2.67bn) from the government and be topped up over time with tax revenues from offshore oil and gas production.
Climate campaigners in the UK and abroad were quick to condemn the decision, while a leading legal expert told Climate Home News it goes against the advice of the International Court of Justice. Meanwhile, the government’s own documents reveal that it recognises the drilling could damage the UK’s reputation and its ability to push forward the global transition away from fossil fuels.
“Climate leadership” blow
The 92-page decision document says Fahnbulleh “acknowledges that international standing on climate is important and accepts that a decision to grant consent may not further the UK’s international climate leadership.”
It adds: “She acknowledges concerns about the potential implications for the UK’s credibility and influence – including the difficulty inherent in encouraging other states to move away from fossil fuel production while the UK continues, in a limited and transitional way, to draw on its own domestic resources.”
While noting that Jackdaw has not been issued with a new license – just permission to extract gas – the document says Fahnbulleh “accepts this does not fully resolve the underlying tension in the UK’s position” but “considers this alongside the substance of the UK’s wider record [on emissions reduction], which remains significant”.
It continues that she accepts these concerns are “legitimate” and weigh against approving gas extraction, but only gives this argument a “moderate negative weight” set against the benefits of gas production.
“Huge” wrong signal
In international climate talks, the UK has long supported the transition away from fossil fuels and is one of very few major oil and gas producers to ban new licenses. Across the North Sea, the Norwegian government continues to make offshore areas available for oil and gas exploration through annual licensing rounds.
Climate experts and campaigners shared the concern, acknowledged in the decision document, that approving Jackdaw could set a precedent for fossil fuel production elsewhere. Sam Fankhauser, professor of climate change economics at Oxford University, said the direct climate impact of Jackdaw is “much smaller than the debate around it would suggest” but the “wrong signal it sends, however, is huge”.
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Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change, said that while Jackdaw’s output will be very small, “it will signal to other fossil fuel producers that they too should carry on with business as usual, less than a month before the COP31”.
Kenyan campaigner Mohamed Adow, director of Power Shift Africa, called the decision “a serious blow to Britain’s international climate credibility” as “the UK cannot expect developing countries to move away from fossil fuels while giving the green light to new drilling in its own backyard”.
International Court of Justice
In July 2025, the International Court of Justice (ICJ) advised that government failure to take appropriate climate action “including through fossil fuel production” may amount to an internationally wrongful act.
The UK voted in favour of a United Nations resolution welcoming the advisory opinion. Yet, in its Jackdaw decision document, it notes that the ICJ opinion is not legally binding and says the UK does not accept the court’s opinion that the customary international law duty to prevent significant harm to the environment applies to climate change.
Fahnbulleh concludes that, although it will have “significant effect on the environment”, gas drilling in Jackdaw “would not lead to significant harm to the environment” – and so does not breach any duty to prevent such harm. Instead, the government document says the duty should be considered “as a matter of policy rather than legal obligation”.
Margaretha Wewerinke-Singh, who led Vanuatu’s legal team pushing for the ICJ’s advisory opinion, told Climate Home News that treating the duty as a matter of policy rather than legal obligation is “not how international law works”. “An advisory opinion is not a judgement,” she said, “but it states the law as it stands, and that law binds the UK whether or not it accepts it.”
“Even as a matter of policy,” she added, “the decision asks the wrong question: whether Jackdaw on its own would cause significant harm. The Court found that accumulated emissions are already causing significant harm. What matters is whether approving new production is consistent with the stringent due diligence the duty requires.”
Public support for decision
While the decision was criticised by climate campaigners and the opposition Green party, polling reported by Politico suggests that 55% of British adults support drilling at Jackdaw, with just 14% opposed. Even supporters of the UK’s net zero target back new drilling by more than two to one, the polling found.
Jackdaw is one of two North Sea oil and gas fields the government has been debating whether to extract more from for months. While Jackdaw is a small gas field, the other, Rosebank, is a much larger field that holds mostly oil.
Rosebank’s emissions are estimated to be around seven times higher than Jack