Classification and Assessment of Aridity over Pakistan...

3. Results and Discussion The aridity maps was prepared by using De Martonne’s Aridity Index, Thornthwaite’s Precipitation Effectiveness Index, Thornthwaite’s Moisture Index, UNESCO Aridity Index and Erinc Aridity Index. These indices showed that most of the southern parts of the country lie between arid to hyper arid where as northern parts lie between semi arid to very humid zone (Fig-3). Analysis shows the climate of northern parts is more variable as compare to southern parts. The reason in the variability of the climate in the northern parts is that this region received rainfall in summer due to monsoon systems (July to September) and in winter due to western disturbances (December to March). Southern parts of the country receive most†¦show more content†¦This is quite unfortunate for our agriculture that evaporative demand and water requirement for crops in whole southern parts of the country is very high as compare to northern parts and it is very difficult to carry out th e agricultural activity in these regions. Climate variability and change profoundly influence social and natural environments throughout the world, with consequent impacts on natural resources and industry that could be large and far-reaching. Climate change due to global warming not only started to impact the weather pattern but also influence the agriculture sector in Pakistan. Pakistan is an agriculture whose majority of the population depends upon agriculture. Glaciers are the big fresh water sources for Pakistan which fulfills the water demands in the agriculture land while rainfall fulfills the water requirement of the barani areas. An increase in temperature was observed in the country especially during the last few decades which accelerate snow melting on glaciers. The increased rate of glacial melting in Himalayas has caused vast lakes to develop, and if these lacks outburst, these can inundate towns and villages below. There is high level of confidence that recent regional changes (rising tendency) in temperature h ave discernable impacts on precipitation, evaporation, stream flow, runoff and other elements of hydrological cycles (Elshamy et al., 2006).