Tropical deforestation could increase risk of heat-related deaths

Outdoor workers in the world’s lower-latitude tropical forests may face a greater risk of heat-related deaths and unsafe working conditions because of deforestation and climate warming, according to a new study.

Researchers found that increased temperatures of 0.95 Celsius (1.7 Fahrenheit) in the deforested areas of Berau Regency, Indonesia, between 2002 and 2018 were linked to roughly 118 additional deaths in 2018, and 20 additional minutes of daily conditions too hot for humans to work in safely.

Future climate warming of 2 Celsius (3.6 Fahrenheit) above 2018’s levels could increase deaths in Berau by 20% (approximately 282 additional annual deaths) and another five unsafe work hours per day—even without greater deforestation.

“Ambient heat exposure and internal body heat from heavy physical work can increase the risk of heat-related illnesses, including heat exhaustion and heat stroke—which can be fatal—as well as acute kidney injury and traumatic injuries,” says June Spector, associate professor and assistant chair of environmental and occupational health sciences in the University of Washington School of Public Health and coauthor of the study in The Lancet Planetary Health.

Researchers point out that the increase in heat-related deaths with a 2 Celsius rise in global temperatures would be comparable to mortality from other long-term public health challenges in Asia, such as tobacco smoking.

In addition, they write, “workers in Berau are already adapting to hotter temperatures due to deforestation, suggesting those engaged in outdoor work may already be approaching their adaptive capacity through behavioral adaptations.”

For the study, researchers used publicly available and secondary data such as satellite monitoring of forest cover, temperatures, climate models, population densities, and the Global Burden of Disease report published annually in The Lancet. Researchers focused on Berau as an area emblematic of tropical forest regions facing rapid deforestation.

“Approximately 800 million people live and work in the world’s tropical forest nations,” Spector says. “These forests can act as natural air conditioners and sequester carbon, thus having implications for both climate change adaptation and mitigation. Information from this modeling study should be considered in discussions about trade-offs between economic welfare, human health, the natural environment, and decisions about climate change adaptation and mitigation.”

Additional coauthors are from The Nature Conservancy, Indonesia’s Mulawarman University, and the University of Washington.