Spatiotemporal Changes in Rainfall and Droughts of Bangladesh for 1.5º and 2ºc Temperature Rise Scenarios of CMIP6 Models

Abstract An alteration of rainfall variability and changes in rainfall driven extremes have been noticed across the globe with rising earth temperature. Such changes will undoubtedly be more devastating for agriculture-based developing countries. Possible changes in rainfall and droughts due to 1.5º and 2ºC temperature rise scenarios have been evaluated in this study for Bangladesh, which is widely referred to globally most climate change susceptible country. Projections of global climate models (GCMs) of the coupled model intercomparison project phase 6 (CMIP6) for two shared socioeconomic pathway (SSP) scenarios, SSP-119 and SSP-126 were used for this purpose. The results showed an increase in annual rainfall over Bangladesh for both scenarios. However, the changes in rainfall variability would cause a drastic change in the drought pattern. Overall, drought frequency may decrease in the drought-prone western region up to -50% and increase in the east up to 50 to 70%, making droughts more homogeneously distributed over the country. However, a higher increase in the east than a decrease in the west for SSP119 indicates a possible shift in the country's drought-prone region. Comparison of drought scenarios for SSP119 and SSP126 revealed a 0.5ºC further rise in temperature might cause an increase in extreme drought frequency by 30% in the central-eastern region. Bangladesh should take effective drought mitigation measures to sustain its agricultural development.