Exploring Climate Change Effects on Drought Patterns in Bangladesh Using Bias-Corrected CMIP6 GCMs

Droughts, intricately tied to precipitation and temperature pattern alterations, pose formidable challenges to the agricultural and environmental domains in monsoon-dominant tropical regions such as Bangladesh. This study's primary objective is to enhance our understanding of the intricate interplay between climate change and drought dynamics in monsoon-dominated tropical Bangladesh. The study provided a unique and comprehensive future drought assessment by employing bias-corrected CMIP6 data and harnessing multimodal ensemble (MME) methodologies. Focusing on the near future (2020–2049) and the far future (2060–2079) against a 1985–2014 benchmark, under shared socioeconomic pathways SSP2-4.5 and SSP5-8.5, the study combined the strengths of SPEI-3 and run-theory analysis to ensure robust projections. The analysis reveals a noteworthy increasing trend for both SSPs in all three climate variables (rainfall, temperature, and evapotranspiration). The spatial distribution of these variables exhibits variations based on geographic location, future period, and SSPs. The drought projections indicate a decrease in mean drought frequency in Bangladesh in the near future, followed by a rise in the far future. However, regional discrepancies are observed, with the northeastern region anticipated to experience an increase in drought frequency in the far future, potentially reaching up to 14%. In contrast, the northwestern region remains relatively less impacted in the near future than the northeastern region. Furthermore, the study identifies that long-duration droughts (> 6 months) are likely to concentrate in the southern areas in the near future, shifting to the central to southern coastal belt in the far future. Additionally, the mean severity of drought events exhibits higher magnitudes for both future periods than the reference period. Overall, the findings highlight the regional disparities in drought frequency changes and emphasize the escalating severity of drought events in the future, underlining the urgency for policymakers and stakeholders to develop effective strategies for climate adaptation and resilience in changing climate conditions.