Effects of large-scale deforestation on precipitation in the monsoon regions: Remote versus local effects

Significance Biogeophysical effects such as albedo and evapotranspiration changes due to deforestation were shown by several studies in the past to exert strong influence on local surface temperatures. In this study, we assess the remote versus local effects of large-scale deforestation on precipitation in the monsoon regions of the world. In contrast to the dominant role of local effects on temperature changes, we find that the remote effects have a larger influence than local effects on shifting the location of the Intertropical Convergence Zone and hence precipitation in all the monsoon regions. This result has important implications for assessing the net benefits of climate change mitigation strategies such as afforestation/reforestation and for understanding changes in monsoon rainfall in past climates. In this paper, using idealized climate model simulations, we investigate the biogeophysical effects of large-scale deforestation on monsoon regions. We find that the remote forcing from large-scale deforestation in the northern middle and high latitudes shifts the Intertropical Convergence Zone southward. This results in a significant decrease in precipitation in the Northern Hemisphere monsoon regions (East Asia, North America, North Africa, and South Asia) and moderate precipitation increases in the Southern Hemisphere monsoon regions (South Africa, South America, and Australia). The magnitude of the monsoonal precipitation changes depends on the location of deforestation, with remote effects showing a larger influence than local effects. The South Asian Monsoon region is affected the most, with 18% decline in precipitation over India. Our results indicate that any comprehensive assessment of afforestation/reforestation as climate change mitigation strategies should carefully evaluate the remote effects on monsoonal precipitation alongside the large local impacts on temperatures.