REGIONAL CLIMATIC RESPONSE TO GLOBAL WARMING AND AGRICULTURE IN PAKISTAN

Abstract

Human-induced anthropogenic variations cause a significant change in the local climate, which in turn lead to variations in different climatic regions. The effects of global warming have wide spatial variability, feedback of climate change, like, surface temperature towards precipitation, surface, and subsurface runoff are critical. As the climate, variability is critically important for nature and society, especially if it increases in amplitude and fluctuations become more persistent. However, the issues of weather surface temperature is changing, and if so, whether this has a positive or negative impact on precipitation, surface and ground runoff, and theirs distinguish response to different climate classes, are subjects of ongoing debate. The current research is mainly concerned with distinguishing the response of surface temperature on the precipitation, storm surface run off, and subsurface runoff on different climate classes over the mainland of Pakistan, for a time duration of 71 years, from 1948–2018. Here, we used monthly based two sets of GLDAS (Global Data Assimilation System) datasets i.e. GLDAS-2.0 (1948-2010) and GLDAS-2.1 (2011-2018) having the spatial resolution of 0.25°×0.25° for surface temperature, precipitation, and runoff. While, for regional based climatic classification, Köppen Grignard climate classification map was used. The spatial-temporal trend of all the involving parameters has been estimated using Mann-Kendall’s trend. Spatial-temporal variation in the precipitation, surface temperature, and runoff fluctuations have been detected in different climatic regions. We showed that annually based variability of surface temperature has positive feedback over the surface runoff over the entire region as well as different climate regions of Pakistan. Despite the declining precipitation trend, the temperature seems to be a major cause of the melting of glaciers leading to an increase in the runoff. Based on our findings of established trends and corresponding mechanistic ‘feedback’ we hypothesize that increasing temperature might risk severe water shortage and cause disastrous floods in the future. Furthermore, different climatic zoning’s surface temperature variability contributed to observed variation in the precipitation, surface, and subsurface runoff variability, which in turn contributed to the persistent droughts. Changes in surface temperature and their impact on precipitation and runoff deliver valued evidence for understanding the region’s sensitivity over the entire region in Pakistan.