Deforestation-fuelled heat is making work increasingly intolerable for millions across Tropics

Arlington, VA – High-profile pledges made at the recent UN Climate Change Conference COP26 in Glasgow haven’t come a moment too soon for communities on the front lines of forest loss, according to a new study published today in the journal One Earth that highlights the extent to which local temperature rises in the world’s tropics – compounded by accelerating deforestation – are already jeopardising the wellbeing and productivity of outdoor workers.   

The study – authored by a multidisciplinary team from Duke University, the University of Washington, and The Nature Conservancy – compares established recommendations on safe working conditions with satellite and population data to show how warming associated with recent deforestation (between 2003-2018) has increased heat exposure for 4.9 million people globally, including 2.8 million outdoor workers.

Decreases in safe working hours were found to be particularly significant in deforested areas, compared with regions where the majority of tropical forest remains intact. The study also highlights disproportionate heat exposure for populations working in parts of Brazil – warning that future global warming projections, compounded by unchecked forest loss, will only exacerbate this situation. In the states of Mato Grosso and Pará, for example – even in the unlikely event of no further deforestation or population growth – the study projects that future global warming of +2°C relative to the present could see more than a quarter of a million people lose two further hours of safe working time per day compared with 2003.

Commenting on the study’s significance, lead author Luke Parsons of Duke University – who led much of the research while in his previous role at the University of Washington – said: “Our findings highlight the vital role tropical forests play in effectively providing natural air-conditioning services for populations vulnerable to climate change – given these are typically regions where outdoor work tends to be the only option for many, and where workers don’t have the luxury of retiring to air-conditioned offices whenever the temperature rises to intolerable levels.”

Senior co-author Nick Wolff from The Nature Conservancy added: “We already knew that tropical deforestation is associated with localised temperature rises, but given the accelerating warming being experienced across the planet, we’re calling for an urgent redoubling of research into how these changes are impacting vulnerable human populations across the Tropics. The various commitments to halting and reversing deforestation that came out of Glasgow were just a start – now we need to see this goodwill rapidly converting into tangible action on the ground.”

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Notes for Editors

Parsons L.A., Jung J., Masuda Y.J., Vargas Zeppetello L.R.V., Wolff N.H., Kroeger T., Battisti D.S., Spector J.T. Tropical deforestation accelerates local warming and loss of safe outdoor working hours. One Earth.

https://doi.org/10.1016/j.oneear.2021.11.016

Additional quotes

• Luke Parsons, Duke University (Lead author)

“Over the last 15 to 20 years, there is a huge disproportionate increase in lost safe work time for people in deforested areas versus people in forestated areas”  

“Although there was a relatively small amount of global climate change over this time period, the increase in humid heat exposure for people living in deforested locations outpaced the changes in heat exposure for people in forested locations.” 

“I’m consistently amazed by the ability of intact tropical forests to moderate local climate- cutting these trees down instantly removes the cooling services that the forests provide, and can make it really, really hot.” 

“For me, this research highlighted two messages: One, that removing tropical rainforest is not only bad for global climate change, but is also bad for local ecosystems and people. And two, if we can prevent tropical deforestation, there is a tangible benefit for the people living in areas with tropical forest.”