Impacts of Climate Change on the Construction of Homogeneous Climatic Regions and Ensemble Climate Projections using CMIP-6 data over Pakistan

Abstract

Climate change has caused several threats that go beyond the impacts on Pakistan. The continued rise in temperature may result in more sever extreme events. This study is conducted to check the impacts of climate change on the construction of Ho mogeneous Climatic Regions (HCR’s) in Pakistan based on Reconnaissance drought index (RDI) and make ensemble climate projections over these HCR’s. By using max imum, minimum temperature, and precipitation data of baseline period (1984-2014) and future period (2015-2044) for 47 metrological stations in Pakistan. The HCR’s are constructed using the L-moment technique and cluster analysis, which yielded five CR’s. We have used the ensemble data based on the outputs of Global Climate Models (GCM’s) data using the weighted average technique and K-fold cross-validation with a regression model for assigning weights to all GCM’s. In order to assess the impacts of climate change on the construction of HCR’s, first we develop HCR’s for observed and ensemble baseline data to evaluate the ensemble data. Then the HCR’s are constructed for the future duration (2015-2044) for ensemble climate data based on the outputs of seven GCM’s with Shared Socioeconomic Pathway (SSP) 4.5 and SSP 8.5. According to the results, some stations are discordant in the future due to climate change under both SSP’s. It is noted that the minimum and maximum temperature will rise in future, with the most significant increases predicted for region 3 and 5 with SSP 4.5 and 8.5. This study’s results will be useful for planners and policymakers to understand the effect of climate change on HCR’s in Pakistan and can guide decision-makers on water management, agricultural planning, and disaster management.