be affected by water stress. UNDP (2006) has estimated a 30% decrease in crop yields in Central and South Asia by the mid 21st century due to increased temperatures and water stress. At the same time, crop yields may increase at higher altitudes and latitudes because of decreased frost and cold damage.
Changes in water flow can affect human health in a number of ways. Higher temperatures may lead to increased endemic morbidity and mortality due to diarrhoel and vector-borne diseases such as malaria, primarily associated with floods and droughts in the Himalayas (ICIMOD, 2007), but pos- sibly also in other mountain regions. A warmer climate at higher altitudes may however also reduce the need for fuel wood and thus reduce the frequency of associated respiratory diseases which are often prevalent in mountain communi- ties. Mountain infrastructure such as hydropower plants,
CASE STUDY Impact of climate change in the Hindu Kush-Himalaya mountains on water resources and
overall economy of Pakistan Amir Muhammed, National University of Computer and Emerging Sciences, Islamabad, Pakistan
Pakistan is a low-income developing country with widespread poverty and related socio-economic problems. Agriculture is the dominant sector of the national economy. Being mainly an arid to semi-arid country, agriculture production is largely dependent on the availability of irrigation water. Pakistan has one of the largest man-made contiguous irrigation systems in the Indus basin which is based on the water available from the Indus River and its tributaries. Part of the Indus river flow is provided by glacial melt from the glaciers of the Himalayan Mountains, the proportion depending on location.
Pakistan desperately needs to increase its agricultural produc- tion to meet the growing needs of the burgeoning population and to improve its economy. The country is already short of irrigation supplies to meet the current requirements. Climate change scenarios for the next about 50 years project higher temperatures in the high Himalayas resulting in more rapid melting of the glaciers which are an important source of water of the Pakistani rivers. It is projected that after initial increase in the river flows for 2–3 decades, the flows will decrease sub-
stantially resulting in greatly reduced supplies in the vast irriga- tion system. This will result in a major setback to the national agriculture and the overall economy. Several comprehensive studies have been undertaken on the overall availability of wa- ter supplies and the national requirements for the irrigation, domestic and industry sectors and these predict a major short- fall in the availability of water even for the most urgent require- ments. This critical situation requires comprehensive analysis and identification of measures to mitigate the situation, arising mainly from climate change in the high mountains resulting in rapid melting of the glaciers and eventually shrinking of the glacier size and reduction in the resulting river flows. Reduced water availability coupled with the increase in ambient temper- ature in most parts of Pakistan will result in a critical situation for the national economy. Some of the measures being consid- ered are building of additional dams to store surplus water dur- ing monsoon season, change in the cropping patterns to suit the changed climatic situation and water availability, increased emphasis on water use efficiency and gradual reduction in area under water-intensive crops like rice and sugarcane.
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roads, bridges and communication systems are at risk with climate change and more variability in water runoff. With in- creased frequencies of landslides and flash floods, technical installations will become more vulnerable, and reduced water flow in dry seasons will make it even more difficult to meet energy demands.
Other effects may be related to changes in forest ecosystems and forest productivity. Tourism could be both positively and nega- tively affected. More natural hazards could mean increased dan- ger when travelling across high mountain routes and possibly also reduced attractions if mountain environments lose signifi- cant portions of the glacial landscape. At the same time, warmer and drier periods in parts of the annual cycle could also make it more attractive for some tourism segments to travel at higher altitudes (Benniston, 2003; Jianchu et al., 2007).
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