The paper by Carlos A. Nobre, Piers J. Sellers, and Jagadish Shukla examines the impact of deforestation in the Amazonian region on regional and global climate. Using a coupled numerical model of the global atmosphere and biosphere (Center for Ocean-Land-Atmosphere GCM), they found that replacing tropical forests with degraded grasslands (pasture) led to a significant increase in mean surface temperature (about 2.5°C) and reductions in annual evapotranspiration (30%), precipitation (25%), and runoff (20%). These changes were most pronounced during the dry season, with larger diurnal fluctuations in surface temperature and vapor pressure deficit observed in deforested areas. The reduction in precipitation was larger than the decrease in evapotranspiration, indicating a reduction in regional moisture convergence. The study also noted an increase in the length of the dry season in the southern half of the Amazon Basin, which could have serious implications for the reestablishment of tropical forests, as rainforests only occur where the dry season is very short or non-existent. An empirical bioclimatic scheme based on an integrated soil moisture stress index was used to derive the movement of the savanna-forest boundary in response to simulated climate change due to large-scale deforestation. The implications of these changes for adjacent regions are discussed.The paper by Carlos A. Nobre, Piers J. Sellers, and Jagadish Shukla examines the impact of deforestation in the Amazonian region on regional and global climate. Using a coupled numerical model of the global atmosphere and biosphere (Center for Ocean-Land-Atmosphere GCM), they found that replacing tropical forests with degraded grasslands (pasture) led to a significant increase in mean surface temperature (about 2.5°C) and reductions in annual evapotranspiration (30%), precipitation (25%), and runoff (20%). These changes were most pronounced during the dry season, with larger diurnal fluctuations in surface temperature and vapor pressure deficit observed in deforested areas. The reduction in precipitation was larger than the decrease in evapotranspiration, indicating a reduction in regional moisture convergence. The study also noted an increase in the length of the dry season in the southern half of the Amazon Basin, which could have serious implications for the reestablishment of tropical forests, as rainforests only occur where the dry season is very short or non-existent. An empirical bioclimatic scheme based on an integrated soil moisture stress index was used to derive the movement of the savanna-forest boundary in response to simulated climate change due to large-scale deforestation. The implications of these changes for adjacent regions are discussed.