Deforestation leads to climate change that harms the remaining forest

In an article published today in Nature Communication, a team led by scientists from the University of California, Irvine, using climate models and satellite data, reveals for the first time how protecting tropical forests can generate climate benefits that enhance carbon storage in nearby areas .

Many climatologists use computer simulations to mimic the planet’s climate as it exists today and how it might exist in the future as humanity continues to emit greenhouse gases. These models rely on precise measurements of all moving parts of the climate system, from the amount of sunlight that hits and warms the climate, to the response of forest biomass to changes in temperature, precipitation and carbon dioxide levels. atmospheric.

The list of moving parts is long, and one part that has so far gone unmeasured is the extent to which deforestation in tropical rainforests like the Amazon and Congo contributes to additional forest loss due to its effect on the regional climate.

“We used Earth system models to quantify the climate impact of tropical deforestation today,” said lead author Yue Li, UCI Postdoctoral Fellow in Earth System Science. “Then we used this information with satellite observations of forest biomass to determine how nearby forests are responding to these changes.”

Jim Randerson, UCI Professor of Earth System Science, added: “This paper shows that avoiding deforestation produces carbon benefits in neighboring regions due to climate feedbacks.”

He explained that for a new patch of deforestation in the Amazon, the resulting regional climate changes resulted in an additional loss of 5.1% of total biomass in the entire Amazon basin. In Congo, the additional loss of biomass due to the climatic effects of deforestation is about 3.8%. Tropical forests store about 200 petagrams of carbon in their aboveground biomass. Since 2010, deforestation has removed about 1 petagram of this carbon every year. (A petagram equals 1 trillion kilograms.)

Until now, climate modellers have not taken tree mortality into account in their climate simulations due to lack of data. But by combining satellite data with climate variables, they obtained insights into the sensitivity of carbon stored in vegetation to climate change resulting from tree mortality and fires.

“Deforestation has ramifications on forests growing elsewhere, due to its consequences on air temperature and rainfall in the region,” said co-author Paulo Brando, UCI Professor of Earth System Science. “Until recently, however, it was very difficult to isolate the effects of deforestation.”

By developing new estimates of regional carbon losses due to climate change induced by deforestation in the Amazon and Congo, the team has provided information that will help scientists refine their models. This “could help us design better climate solutions,” Randerson said. By knowing exactly how much biomass is lost to this activity, he explained, policymakers can make a stronger case for why it is worth curbing deforestation, because they can now better describe the effects. training.

Dave Lawrence of the National Center for Atmospheric Research and Hui Yang of the Max Planck Institute for Biogeochemistry in Germany joined Brando, Li and Randerson on this project, funded by the US Department of Energy’s Office of Science and NASA.

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Material provided by University of California – Irvine. Note: Content may be edited for style and length.

Teresa H. Sadler