Forest loss causes 28,000 heat-related deaths yearly

Estimated reading time: 7 minutes

Research published in Nature Climate Change reveals that forest loss and tropical deforestation caused an additional 28,000 heat-related deaths annually between 2001-20, totalling over half a million heat-related deaths across two decades.

The first study to examine human health impacts of deforestation-induced warming found that forest loss alone drove 0.45°C of warming in tropical regions, exposing 345 million people to dangerous local heating. Six out of every 100,000 people living in deforested areas died from deforestation-induced warming, with Vietnam recording the highest mortality rate at 29 deaths per 100,000 people. The research highlights how forest destruction disproportionately affects vulnerable Indigenous and traditional communities who face limited access to cooling resources. Scientists warn this reframes deforestation as a critical public health emergency requiring urgent forest protection. #BoycottPalmOil #Boycott4Wildlife

Tandon, A. (2025, August 27). Warming due to tropical deforestation linked to 28,000 ‘excess’ deaths per year. Carbon Brief. https://www.carbonbrief.org/warming-due-to-tropical-deforestation-linked-to-28000-excess-deaths-per-year/

---

Tropical deforestation strongly linked to heat-related mortality

Research published in Nature Climate Change reveals that Forest loss claims thousands of lives each year. According to findings, the main reason for deaths is lethal heat exposure.

Researchers found that warming driven by deforestation caused an extra 28,000 heat-related deaths annually across Africa, South America and Asia between 2001-20. This represents the first research to examine human health impacts of warming caused specifically by tropical deforestation rather than fossil fuel emissions.

Lead author Dr Carly Reddington from the University of Leeds described it as the “first study to look at human health impacts of tropical deforestation-induced warming“. The research team analysed 1.6 million square kilometres of tropical forest loss globally over the two-decade period.

The study found that deforestation alone drove an average of 0.45°C of warming in the tropics over 2001-20, accounting for 64% of total warming in regions with tropical forest loss. By comparing deforested regions with neighbouring areas that maintained forest cover, researchers discovered deforested areas experienced 0.7°C warming whilst forested areas saw only 0.2°C increases.

Regional temperature impacts varied dramatically. Surface temperatures increased by 0.34°C in tropical Central and South America, 0.1°C in tropical Africa, and 0.72°C in Southeast Asia. The research revealed that “areas of forest loss coincide with areas of strong positive change in temperature across many regions of the tropics”.

Deforestation-induced warming is a human health emergency

The human health consequences proved devastating. Tropical forest loss exposed 345 million people to local warming beyond existing global warming impacts, with just over three-quarters experiencing warming directly caused by forest loss. The study found that six out of every 100,000 people living in deforested areas died as a result of deforestation-induced warming.

Forest loss in Vietnam causes heat-related deaths

Vietnam recorded the most severe mortality impact, with an average of 29 deaths per 100,000 people. The research showed that tropical deforestation-induced warming accounted for 39% of total heat-related mortality from combined global climate change and deforestation effects in forest loss locations.

Dr Nicholas Wolff from the Nature Conservancy, who was not involved in the study, called the research “sobering,” noting it “reframes tropical deforestation as not only a carbon emissions and ecological issue, but also a critical public health concern”.

The study emphasised that vulnerable populations suffer disproportionately. The research stated: “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”.

Forest loss eliminates crucial cooling effects through reduced evapotranspiration, where trees move water from soil through their roots and leaves, cooling surrounding air when it evaporates. When forests disappear, this natural air conditioning system vanishes.

The mortality calculations used temperature-mortality relationships that vary between countries, as populations in hotter regions generally show better adaptation to extreme heat. Researchers compared real mortality rates with counterfactual scenarios where forests remained intact to determine deforestation’s lethal impact.

Dr Vikki Thompson from the Royal Netherlands Meteorological Institute, who was not involved in the study, emphasised the findings’ global relevance: “We can reduce impacts of extreme heat by planting more trees and reducing deforestation everywhere, on both local and international scales”.

The study noted that deforestation drives additional health problems beyond heat mortality, including increased zoonotic diseases like malaria. Researchers warned their warming measurements focused only on areas within one square kilometre of forest loss, though “deforestation is associated with warming up to 100km away”.

Learn more

Tandon, A. (2025, August 27). Warming due to tropical deforestation linked to 28,000 ‘excess’ deaths per year. Carbon Brief. https://www.carbonbrief.org/warming-due-to-tropical-deforestation-linked-to-28000-excess-deaths-per-year/

Reddington, C. L. et al. (2025) ​Tropical deforestation is associated with considerable heat-related mortality, Nature Climate Change, doi:10.1038/s41558-025-02411-0

Tandon, A. (2025, August 27). Warming due to tropical deforestation linked to 28,000 ‘excess’ deaths per year. Carbon Brief. https://www.carbonbrief.org/warming-due-to-tropical-deforestation-linked-to-28000-excess-deaths-per-year/

ENDS

---

Read more about deforestation and ecocide in the palm oil industry