Uncertainty and the changing hydroclimatology of the Amazon

Using a spatially-explicit model, we have projected potential Amazon landscapes based on two possible development scenarios and total forest removal to represent uncertainty in future land cover. We conducted Monte Carlo simulations with a regional climate model driven by these landscapes and by different years to include atmospheric uncertainty. Absent restraints on development, we find that certain areas can expect annual rainfall declines of 3-5% that persist in spite of introduced uncertainty. These declines are strongly tied to key landscape features. Land cover and land use change associated with major roads, not ENSO events or other annual atmospheric features, leads to reduced rainfall. For the case of total deforestation we found an average annual decline in rainfall of 10-20% across the entire basin.