GCM - Derived Future Climate of Arid Western India and Implications for Land Degradation

摘要

An analysis of the present and future patterns of rainfall, aridity, and wind and water erosion potentials in arid western part of Indian subcontinent, based on GCM data for A2 scenario, revealed that only few GCMs could be used with greater confidence. The study suggests strong possibility of a prolonged drought phase during 2021-2025, which may continue with some respite till the mid-century. It also shows the likelihood of aridity spreading beyond the present eastern boundary of the region duringthe same period. Since wind strength is likely to increase gradually and soils dry, the wind erosivity is expected to increase manifold across Thar Desert and Megathar region, especially from the middle of this decade, destabilizing the sandy landscape over a much larger area and contributing more to the atmospheric dust load. Likely periods of higher monsoon rainfall than the 1951-2000 mean have been identified, which may encourage higher fluvial erosion along the Aravalli foothills and Kachchh mainland due to increasing rainfall intensity that was predicted earlier by PRECIS model. Since the degradation processes are already getting accentuated by increased human pressure on the vulnerable land resources, and since there is an apprehension that normal monsoon behavior of the subcontinent has already started to get affected by the degradation processes in the region, serious efforts are needed to understand the atmosphere-land-human interaction mechanism for improving the conditions.