Projected climatic exposure and velocities of precipitation extremes over India and its biogeographic zones

Abstract

Climate change is leading to alterations in the dynamic and thermodynamic climate systems worldwide, including the Indian summer monsoon (ISM), which supports more than a billion population and drives the Indian economy. The anthropogenic climate change induces unprecedented transformations in the natural and ecological systems, such as the increased probability of precipitation extremes, changes in their frequency, duration and spatial variabilities. This current study aims to project the regional landscape-based metric, velocity of climate change (VoCC) and associated climatic exposure regarding precipitation extremes (PEs) for India and its different biogeographic zones. The climate velocities of mean precipitation, 95th, 99.5th and 99.9th percentiles of precipitation for the ISM season are presented for the historical and three projected time slices under the RCP8.5 scenario. ROM, a state-of-the-art regional earth system model over the CORDEX-South Asia domain, was used in the study. It was observed that the intense and very intense rainfall (95th, 99.5th and 99.9th percentiles) was enhanced over most of the study region in the near- and mid-future compared to the far-future. The intense rainfall exhibited higher climate velocity than the mean and very intense precipitation in the near-future. The southern part of the Indian subcontinent usually displayed positive VoCC values for the historical and near-future time slices compared to the northern part of the Indian peninsula, particularly the intense and very intense precipitation. The climatic exposure for all-India was also higher in the near- and mid-future compared to the far-future, especially for the intense rainfall followed by the mean and very intense rainfall. These results suggest the need for focusing the adaptation and mitigation measures towards managing the near-term impacts of PEs in relation to the long-term impacts, especially on the country's diverse flora.