Impacts of Climate Change on the Construction of Homogeneous Climatic Regions in Pakistan and Climate Projections

Abstract

The effects of climate change belong to the most severe significant challenges to the environmental problems that confronting humanity, affecting agricultural production, fresh water supply, natural ecosystems, health, and other areas. Climate change’s adverse effects are already being experienced throughout the globe in the form of increasing occurrence and severity of severe climatic events including storms, droughts, and floods. Pakistan has several natural disasters, including floods, droughts, and cyclones. When such risks are linked with vulnerabilities such as poverty and inadequate political choices and actions, individuals become more vulnerable to the effects of hazards. The consequences of changes in the climate have posed several threats, far more than the effects on Pakistan as the temperature is constantly rising, and this might lead to an increase in the intensity of severe incidents.This study analyses the effects of climate change on climatic zones that are established by using the data on rainfall and the temperature for the baseline period 1976-2005. The data of 55 meteorological locations of Pakistan are acquired and formed homogeneous climatic regions (HCRs) based on reconnaissance drought index (RDI). For the construction of HCRs, two statistical methods were performed. In the beginning, we employed agglomerative cluster analysis along with association of the ward’s linkage with the Euclidean distance to identify CRs by using site characteristics of the sites, which identify five climatic regions (CRs). In order to satisfy the homogeneity of HCRs, two statistical measures were used premised on the technique of L-moments: the homogeneity measure and discordancy measure, performed after regional adjustments. These HCRs were evaluated on the REgional MOdel (REMO) model for the baseline period 1976-2005. REMO with representative concentration pathways (RCP) 4.5 and RCP 8.5 is used for constructing the HCRs on different future time intervals, that is, first future time interval (2011-2040), second future time interval (2041-2070), and third future time interval (2071-2100), to observe the impacts of climate change and made climatic projections on these constructed regions. The projections were compared with the reference period 1976-2005. The results showed that in the future the homogeneity of the regions would be affected because of changes in climate, and some stations will be discordant under both future scenarios due to increased temperature and decreased precipitation. It is observed that the minimum temperature and maximum temperature will increase in the future, and a major increase in temperature is projected in 2071-2100 with RCP 4.5 and RCP 8.5. This study will assist for the foreseeable future planning of climate change, water management , and irrigation in the country’s impacted regions.