Climate is an important force in driving the agricultural productivity of a particular area either directly (by influencing the crops and livestock) or indirectly (by disturbing the water resources). In the past few decades rapid changes has been observed in the climatic conditions around the globe posing some serious threats to water resources and ultimately the agriculture, especially in the developing countries. Before we go into the depth of the topic it is mandatory to discuss few important causes of the changing climatic conditions. The rising atmospheric temperature is generally regarded as the important factor in this regard. The rising concentration of the greenhouse gases in the atmosphere is mostly found associated with global warming. In the past two and a half century nearly 30% rise in CO2 concentration and 150 % rise in the CH4 concentration has been observed, which is mainly because of rapid urbanization and burning of fossil fuels. This change in the global temperature is resulting in shifted rainfall patterns. As a result of which the severity and frequency of drought periods is increasing. All these facts are in the end negatively affecting the water resources.
Pakistan is basically located in the near east. According to FAO reports total 29 countries fall in the near east category and it is regarded as the poorest area on the globe in terms of water resources because of high levels of aridity. Climate of Pakistan is also arid to semiarid. However Pakistan is fortunate that it has three major rivers Chenab, Indus and Jehlum flowing from bordering regions and these play an important role in sustaining the irrigation and agricultural productivity in Pakistan. In Pakistan a major impact of the changing climatic conditions has been observed on the water resources in the near past. Among these rivers Indus is the major one and its proper use and development is very much essential for sustaining agriculture. Basically it is snow-fed river and due to the rise in the atmospheric temperature the extent of the snow is reducing day by day as a result of which the water availability in it is also decreasing. According to the predictions of certain models the runoff in the river Indus will decrease by almost 25 percent by 2050. If we talk about the population of Pakistan it is increasing at a rate of nearly 2.5 % per annum. As a result of which the demand and use of the water is also rising rapidly. In addition as the industrial activity will increase it will require more water and as a result of which the water resources will be over exploited.
Global climatic changes and the water resources are deeply related to each other. Rain is regarded as the major source of fresh water. In the changing climatic scenario a rapid shift in the precipitation pattern has been observed. These shifts in the precipitation patterns are very much devastating for the countries like Pakistan as the climate is already arid to semi-arid. In addition the rapidly rising temperature will cause the glaciers to melt away as a result the water in snow-fed rivers will decrease in long run and rapid melting can at times results in extreme weather events like floods on other hand. According to a recent report of IPCC the frequency of the intense precipitation days and floods is expected to rise as a result of global warming. The report also suggest that the frequency and severity of drought will also increase on other hand due to the shifted precipitation patterns
Now if we look at the river flow in the recent past the water flow in the rivers of Pakistan had increased by almost 40% during 1990s to 2000. This increased river flow is a major indicator of the effects of changing climatic conditions on the water resources as the snow melt due to global warming will initially increase the water level in the snow-fed rivers but ultimately the water reservoirs will shrink in the long run. The other problem Pakistan is facing is the inappropriate distribution of the precipitation which is causing frequent drought spells on one hand and extreme weather events on other hand. It is therefore need of the hour to pay attention to the changing climate scenario. Government should pay more attention for building more water reservoirs and try to conserve as much water as they can. In addition the policies should be made keeping in view the predictions of climate change experts and models.
Shakeel Ahmad Anjum, Ayesha Farooq, Usman Nazir, Imran Khan
Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan