How Cutting Down Tropical Forests is Costing Lives Through Deadly Heat

Animated map showing heat-related mortality rates linked to deforestation across Tropical Central and South America, with darker colors representing higher deaths per 100,000 people.
The maps show regions of Tropical Central and South America (a), Tropical Africa (b), and Southeast Asia (c). Colours show number of deaths per year per 100,000 people located in areas of forest loss (central estimate), aggregated by second-level administration divisions. Boundaries for second-level administration divisions are from GADM (https://gadm.org/index.html).

When we hear about deforestation, many of us think first about disappearing wildlife, endangered species, or the loss of carbon storage that slows climate change. All of that is true, but there’s another hidden danger. Cutting down tropical forests hurts our planet’s biodiversity and directly affects human health. New research shows that losing forests makes people hotter, sicker, and in many cases, more likely to die from extreme heat.

What the Study Found

A recent study published in Nature Climate Change looked at forest loss across the tropics between 2001 and 2020. The researchers found that when forests are cleared, the land surface warms up quickly. On average, deforested areas became almost 0.5 °C hotter than places that kept their trees.

That may not sound like much, but for people living in already hot, humid places, even small increases can push temperatures past safe limits. The study estimated that about 345 million people have been exposed to this extra warming caused by deforestation. That’s nearly the size of the entire U.S. population.

The Human Toll

The warming from deforestation is deadly. According to the study, deforestation is linked to about 28,000 extra heat-related deaths each year (Reddington et al., 2025). These deaths happen because the body can only handle so much heat before heart, lung, or kidney problems set in.

Some of the hardest-hit regions include:

  • Indonesia, Vietnam, and Malaysia, where heat deaths per 100,000 people are among the highest in the world.

  • Nigeria and the Democratic Republic of Congo, which also face significant impacts.

  • Southeast Asia overall, which accounts for more than half of all the deaths linked to deforestation-related heat.

In these countries, outdoor workers, such as farmers and construction workers, are especially vulnerable.

Why the Tropics Are Vulnerable

The tropics, regions close to the equator, are home to over 3.5 billion people. Many of these communities depend on outdoor work for their livelihoods. When forests are cut, not only does the land heat up, but shade disappears too. That makes outdoor work far more dangerous.

Health care access also plays a big role. In many tropical nations, hospitals and clinics are already under pressure, and people may not have reliable access to air conditioning, cooling centers, or emergency care. This limited ability to adapt means heat has a bigger impact on vulnerable groups, such as children, older adults, and outdoor workers.

Other Hidden Dangers

Heat isn’t the only risk linked to cutting forests. Deforestation also leads to:

  • Air pollution from fires: When forests are burned, smoke can spread across entire regions. In past years, haze from Indonesian forest fires exposed tens of millions of people to unsafe air, leading to thousands of premature deaths.

  • Spread of diseases: Clearing forests can increase the spread of diseases like malaria. In some places, standing water left after logging creates ideal breeding grounds for mosquitoes.

Together, these risks make deforestation not only an environmental problem but also a serious public health issue.

What Can Be Done

The good news is that protecting forests can prevent many of these heat-related deaths. Keeping trees standing provides shade, keeps local areas cooler, and reduces harmful smoke. On a larger scale, forests act as a buffer against climate change by storing carbon and releasing moisture into the air.

Steps that can help include:

  • Stronger protections for tropical forests through laws and enforcement.

  • Community-led conservation that involves local and Indigenous groups who know the land best.

  • Investment in health systems and cooling strategies to protect people who already live in areas affected by deforestation.

  • Global cooperation to reduce demand for products linked to deforestation, such as unsustainable palm oil, soy, and beef.

These actions can save thousands of lives each year.

Summing Up

The study’s message is clear: tropical forests aren’t just “carbon sinks” or wildlife havens. They are lifelines for millions of people. Losing them raises local temperatures, increases the risk of deadly heat, and harms human health in ways many of us never considered.

By protecting tropical forests, we preserve ecosystems while protecting people. Safeguarding these forests is a direct investment in healthier, safer communities around the world.


Source: Reddington, C. L., Smith, C., Butt, E. W., Baker, J. C. A., Oliveira, B. F. A., Yamba, E. I., & Spracklen, D. V. (2025). Tropical deforestation is associated with considerable heat-related mortality. Nature Climate Change. Advance online publication. https://doi.org/10.1038/s41558-025-02411-0

Climate Litigation: A Growing Force in the Fight Against Climate Change



As the world faces increasingly severe climate impacts, governments and corporations are being held accountable through a surge of climate-related lawsuits. A recent study, Research Areas for Climate Litigation, conducted by the Union of Concerned Scientists (UCS) in September 2024, highlights the critical role of climate litigation in driving action where traditional policy-making has often fallen short.

The Rise of Climate Litigation

Since 2015, more than 1,800 climate-related lawsuits have been filed worldwide, with at least 230 new cases in 2023 alone. The United States, United Kingdom, and Australia have become the primary hubs for this legal activity, while other regions, especially parts of Africa, have seen limited litigation.

The UCS study emphasizes that this growing body of legal action requires strong scientific evidence to be effective. To that end, scientists and researchers are increasingly collaborating with legal teams to provide the necessary data, helping courts make informed decisions on climate cases. The study aims to bridge gaps between science and law by identifying key research priorities that can strengthen future litigation efforts.

Key Research Areas for Climate Litigation

The study highlights three priority research areas that are essential for advancing climate lawsuits:

  1. Attribution Science: This field connects specific climate impacts to particular sources of emissions. Courts need this science to establish a clear causal link between climate change and its effects, such as extreme weather events. The study calls for more geographically diverse research, particularly in regions like the Global South, where climate data is scarce.

  2. Climate Change and Human Health: Legal arguments are increasingly focusing on the health impacts of climate change. Vulnerable groups, including older adults, infants, people with disabilities, and those in poverty, are especially at risk from worsening air quality, heatwaves, and water scarcity. The study points to a need for more research linking climate change to health outcomes like asthma, cardiovascular diseases, and heat-related illnesses.

  3. Economic Modeling: Courts rely on economic data to assess the costs of climate change. This includes not only the direct damages caused by extreme weather events but also the costs of adapting to a changing climate and the economic opportunities lost due to inaction. The study calls for robust economic modeling that can predict future costs and benefits under different climate scenarios.

Strategic Research Areas for the Future

Beyond the priority areas, the study identifies five strategic research areas where further scientific evidence is needed to support climate litigation:

  1. Legal and Financial Accountability: Holding corporations accountable for their emissions, particularly in industries like fashion and cement, requires more detailed research on how financial institutions contribute to climate change by funding fossil fuel projects.

  2. Disinformation and Greenwashing: The study stresses the importance of exposing and countering misleading claims made by corporations about their environmental practices, which can mislead consumers and delay meaningful climate action.

  3. Fair Share Analysis and Compliance: Understanding whether corporations and nations are meeting their climate goals is critical. The study highlights the need for standardized emissions metrics and tracking, especially for corporations with complex supply chains.

  4. Environmental and Social Impacts: Research on how climate change affects ecosystems, biodiversity, and human communities—especially in remote regions with limited data—is vital for comprehensive environmental impact assessments.

  5. Emissions Accounting and Reductions: Courts need better methods for tracking and reducing emissions, particularly those related to the indirect effects of products, known as Scope 3 emissions. The study also calls for research into the effectiveness of renewable energy credits and other mitigation strategies.

Losses and Damages: A Cross-Cutting Theme

One of the study’s most important cross-cutting themes is losses and damagesthe economic and non-economic harms caused by climate change that can’t be prevented through adaptation or mitigation. The study calls for more research to quantify these losses, especially in terms of intangible cultural heritage, social structures, and ways of life. Understanding these losses is critical for communities seeking reparations for the damage caused by climate change.

Why This Study Matters

As climate litigation accelerates globally, the need for solid scientific research to support these cases becomes more urgent. The UCS study provides a roadmap for scientists looking to contribute to the legal battle against climate change by focusing on areas where their work can have the greatest impact. This research will not only improve the effectiveness of climate lawsuits but also push governments and corporations to take more meaningful climate action.

Summing Up

Climate litigation is emerging as a powerful tool in the fight against climate change. With over 1,800 lawsuits filed since 2015, the legal community is increasingly relying on science to prove the connections between climate change, its impacts, and the entities responsible. The Union of Concerned Scientists’ 2024 study highlights the critical research areas—such as attribution science, health impacts, and economic modeling—that will strengthen these legal efforts.

For those interested in how climate change is being addressed through legal channels, this study underscores the vital role that science plays in holding governments and corporations accountable. As the impacts of climate change worsen, the importance of this intersection between science and law will only grow.


Source: Merner, L. D., Phillips, C. A., & Mulvey, K. (2024). Research areas for climate litigation: 2024 report. Union of Concerned Scientists.

‘Turn off the tap on plastic,’ UN Chief declares amid debate over new global treaty

“Plastics are fossil fuels in another form,” said U.N. Secretary-General António Guterres, “and pose a serious threat to human rights, the climate, and biodiversity.”

By Kenny Stancil, Common Dreams

Hours before the first round of negotiations to advance a global plastics treaty concluded Friday in Punta Del Este, Uruguay, the leader of the United Nations implored countries “to look beyond waste and turn off the tap on plastic.”

“Plastics are fossil fuels in another form,” U.N. Secretary-General António Guterres tweeted, “and pose a serious threat to human rights, the climate, and biodiversity.”

Guterres’ comments elevated the demands of civil society organizations, scientists, and other advocates fighting for robust, legally binding rules to confront the full lifecycle impacts of the plastic pollution crisis. A coalition of more than 100 groups has called for limiting the ever-growing production and consumption of plastic and holding corporations accountable for the ecological and public health harms caused by manufacturing an endless stream of toxic single-use items.

Petrochemical industry representatives who attended the first intergovernmental negotiating committee meeting (INC-1) for a global plastics treaty, by contrast, attempted to bolster fossil fuel-friendly governments’ efforts to slow the pace of talks—convened by the U.N. Environment Program and set to continue off-and-on through 2024—and weaken proposals for action.

In the wake of this week’s opening round of debate, the Break Free From Plastic (BFFP) alliance launched a petition outlining what it calls the “essential elements” of a multilateral environmental agreement capable of “reversing the tide of plastic pollution and contributing to the end of the triple planetary crises of climate change, biodiversity loss, and pollution.”

According to experts associated with BFFP, an effective global plastics treaty must include the following:

  • Significant, progressive, and mandatory targets to cap and dramatically reduce virgin plastic production;
  • Legally binding, time-bound, and ambitious targets to implement and scale up reuse, refill, and alternative product delivery systems;
  • A just transition to safer and more sustainable livelihoods for workers and communities across the plastics supply chain; and
  • Provisions that hold polluting corporations and plastic-producing countries accountable.

BFFP member Graham Forbes, head of the Global Plastic Project at Greenpeace USA, said in a statement that “we cannot let oil-producing countries, at the behest of Big Oil and petrochemical companies, dominate and slow down the treaty discussions and weaken its ambition.”

“If the plastics industry has its way, plastic production could double within the next 10-15 years, and triple by 2050—with catastrophic impacts on our planet and its people,” said Forbes. “The High Ambition Coalition must show leadership by pushing the negotiations forward and calling for more ambitious measures which protect our health, our climate, and our communities from the plastics crisis.”

A global plastics treaty, Forbes added, represents “a major opportunity to finally end the age of plastic, and governments should not let this go to waste. We demand that world leaders deliver a strong and ambitious treaty that will dramatically reduce plastic production and use, open inclusive and justice-centered discussions, and ensure that the next INCs are free from industry interference.”

Center for International Environmental Law (CIEL) senior attorney Giulia Carlini pointed out that profit-maximizing corporations “have deliberately manufactured doubt about the health impacts” of their products in previous treaties that address health issues, such as the World Health Organization Framework Convention on Tobacco Control.

“There is strong scientific consensus that plastics-associated chemicals cause diseases,” Carlini continued. “If the treaty is to succeed in meeting its health objectives, it will be essential to set strict conflict-of-interest policies going forward.”

After more than 145 governments expressed support this week for developing a pact with specific and shared international standards—which could include a ban on single-use items and requirements to ensure reuse and circularity—Eirik Lindebjerg, global plastics policy lead at the World Wildlife Fund, said that “the momentum demonstrated at these negotiations is a promising sign that we will get a truly ambitious treaty with effective global measures to stop plastic pollution” by 2024.

“It has been a very important week in the history of protecting the environment and people,” said Lindebjerg. “This week we saw an encouraging level of agreement, both in formal and informal spaces, on the urgency of seeking a joint solution to this major threat to nature and communities, and to do so in a comprehensive, effective, inclusive, and science-based manner.”

However, he warned, “this is just the first step towards a legally binding global treaty that can help us stop plastic pollution.”

“The next stage of negotiations will be more challenging, as countries must agree on the technical measures and rules,” said Lindebjerg. “Although in the minority, there are also some powerful opponents of global rules and standards, which risk potentially weakening obligations on countries to take action. The push for an ambitious global plastics treaty has only just begun.”

“Millions of people around the world, whose livelihoods and environments are affected by plastic, have their eyes on these negotiations,” he added. “Now negotiators must harness this momentum to push for specific rules to be negotiated as part of the treaty.”

Lindebjerg’s assessment was shared by other summit delegates.

“Negotiations at INC-1 this week demonstrated that the majority of countries are ready to take urgent action to confront the plastics crisis, including by addressing the plastic production that drives that crisis,” said CIEL president Carroll Muffett. “Sadly, it also proved that plastic producers and their allies are equally committed to slowing progress and weakening ambition—from the U.S. insistence that the plastic treaty replicate the weaknesses of the Paris agreement, to last-minute maneuvers by other fossil fuel and petrochemical states to block countries’ ability to vote on difficult issues.”

“Despite these maneuvers, the world made real progress in Punta Del Este,” said Muffett. Robust “global commitments and binding targets remain both necessary and achievable,” she added, but securing them will require “the U.S. and other countries join the rest of the world in pairing claims of high ambition with the policies that high ambition demands.”

While this week marked the first time that governments have met to hash out global-scale regulations to restrict plastic production, the United States and the United Kingdom—the world’s biggest per-capita plastic polluters—have so far refused to join an international treaty to curb the amount of plastic waste destined for landfills and habitats, though both countries are reportedly now open to the idea.

“Over this week, we have seen multiple interventions raising whether the future treaty will be based on national action plans, or global, mandatory targets,” said CIEL senior attorney Andrés Del Castillo. “We know that this will be top of the agenda at INC-2. The failure of countries to fulfill their emissions reduction plans under the Paris agreement shows that we cannot afford another treaty that centers on the whims of its leaders.”

The next session of the conference aimed at creating a global plastics treaty is set to take place in Paris in May 2023.