Amazon forest loss: An all-sky biophysical top-of-atmosphere cooling feedback.

The Amazon rainforest plays a crucial role in regulating Earth's energy and water cycles. The full biophysical impact of deforestation, particularly when mediated by clouds, remains elusive. Using two decades of multisource satellite observations, we isolate biophysical signals of forest loss and present an observation of the all-sky biophysical feedback that integrates surface and atmospheric effects. We find that top-of-atmosphere (TOA) cooling in shortwave and longwave fluxes scales with forest loss fraction, with shortwave dominating. In high-loss areas, shortwave TOA cooling reaches 6.8 ± 0.6 watts per square meter, with cloud-driven albedo increases doubling the effect relative to surface brightening alone. These findings underscore the importance of cloud responses in estimating the climatic impact of forest cover change and support their integration into climate models and land-management policies. Editor's summary: Forests have large impacts on Earth's energy and water cycles, and deforestation is a big part of what controls them. Dror et al. used satellite data to investigate the biophysical effects of deforestation in the Amazon, finding that short-wave and long-wave cooling at the top of the atmosphere, where Earth's net energy balance is determined, scaled with forest loss fraction (see the Perspective by Myhre). The results illustrate the importance of cloud feedbacks in estimating the climatic impact of forest cover change and should help to guide land management policies. —Jesse Smith [ABSTRACT FROM AUTHOR]