Impacts of Tropical Deforestation on Local Climate

Abstract:

Tropical forests play a critical role in maintaining the balance of surface fluxes and strongly influence the local and regional climate. Tropical deforestation is therefore increasingly recognised as an issue of global importance, although the local and regional climate consequences of land-cover changes, and how they vary across the tropics, are still not fully understood. We used remotely-sensed atmospheric and land-surface datasets at 0.05^o resolution to analyse the climate impacts of deforestation from 2001 to 2018 over three tropical forest domains: the Amazon basin, the Congo basin and South-East Asia (SEA). At the local scale, reductions in leaf area index (LAI) and increases in daytime land surface temperature (T) were observed with increasing deforestation across all tropical regions. The Amazon and SEA showed broadly similar responses to deforestation, with increases in annual mean T in excess of 0.5°C, compared to only 0.2°C in the Congo. We found that precipitation did not show a significant response to deforestation in any of the regions. To understand why the climate responses differed between continents, we used multiple linear regression to investigate factors that might influence the temperature response to deforestation. We find that alongside changes to LAI, areas where dry season precipitation was lower showed a stronger temperature response to forest loss. The regional extent of deforestation also impacted the local temperature response to land-use change, with stronger warming in regions with more extensive deforestation and little remaining forest cover in the surrounding area. The results of this study highlight the differences and interconnectivity in local climate responses between the tropical regions.