Impact of Amazonian deforestation on precipitation reverses between seasons

Tropical deforestation was found to cause large reductions in precipitation using a range of observation-based datasets¹. However, the limitations of satellite-based space-for-time statistical analysis have hindered understanding of the roles of reshaped mesoscale atmospheric circulation and regional precipitation recycling at different scales. These effects are considered nonlocal effects, which are distinct from the local effects governed by deforestation-induced reductions in evapotranspiration (ET). Here we show reversed precipitation responses to Amazon deforestation across wet and dry seasons. During the wet season, deforested grids experienced a noteworthy increase in precipitation (0.96 mm month^-1 per percentage point forest loss), primarily attributed to enhanced mesoscale atmospheric circulation (that is, nonlocal effect). These nonlocal increases weaken with distance from deforested grids, leading to significant precipitation reductions in buffers beyond 60 km. Conversely, during the dry season, precipitation decreases in deforested grids and throughout all analysis buffers, with local effects from reduced ET dominating. Our findings highlight the intricate balance between local effects and nonlocal effects in driving deforestation-precipitation responses across different seasons and scales and emphasize the urgent need to address the rapid and extensive loss of forest in the Amazon region.