Climate change and managing water crisis: Pakistan's perspective

Climate change is a global phenomenon manifested mainly through global warming. The International Panel on Climate Change (IPCC) has reported its negative consequences on natural resources, anthropogenic activities, and natural disasters. The El Nino and La Nina have affected hydrologic regimes and ecosystems. It has been observed that the average temperature in 1995 was 0.4°C higher than that in 1895. By the end of the 21st century, 10% of the area of Bangladesh is likely to be submerged by the sea. Most of the islands of Pacific Ocean will disappear. A major part of Maldives will be submerged. The sea level is expected to rise by 30-150 cm. Extreme events such as floods, cyclones, tsunamis, and droughts have become regular phenomena in many parts of the world. Other adverse impacts are proliferation of water-borne diseases, sea water intrusion, salinization of coastal areas, loss of biodiversity, eco-degradation of watersheds and global glacial decline, and haphazard snow melts/thaws. In turn, these factors have serious effect on water resources. Pakistan is confronting similar climate change. Meteorological data reveal that winter temperatures are rising and summers are getting cooler. Temperature is expected to increase by 0.9°C and 1.5°C by years 2020 and 2050, respectively. Water resources in Pakistan are affected by climate change as it impacts the behavior of glaciers, rainfall patterns, greenhouse gas emissions, recurrence of extreme events such as floods and droughts. Severe floods have occurred in the years 1950, 1956, 1957, 1973, 1976, 1978, 1988, 1992, 2010, 2011, and 2012. Pakistan has faced the worst-ever droughts during the period from 1998 to 2004. Pakistan has surface water potential of 140 million acre feet (MAF) and underground water reserve of 56 MAF. It is one of the most water-stressed countries in the world. The per capita annual availability of water has reduced from 5140 m3 in 1950 to 1000 m3 now. It is fast approaching towards water scarcity. To minimize adverse impacts of climate change on the water crisis in Pakistan, the preparation of integrated national, provincial, and local level master plans encompassing technical, social, environmental, administrative, and financial considerations is necessary. It is imperative to implement two simultaneous approaches of adaptation (living with climate change) and mitigation (addressing negativities of climate change). Salient features are integrated management of watersheds/catchments/water bodies, optimum exploitation of present sources, development of new sources, water conservation, adequate drainage, efficient design of water storage, conveyance, distribution and supply systems, utilization of waste water, and regulation of water quality.