The present catastrophic and devastating flooding in Pakistan has not only been caused by exceptionally heavy monsoon rains in the upper Indus basin, but also is the result of accelerated melting of glaciers that feed into the Kabul, Swat, and Indus Rivers. Both phenomena are the result of changing weather patterns in the Himalayan ecosystem, which has been strongly affected by climate change.
By Syed Iqbal Hasnain – Many independent studies, including the United Nations Development Programme report in 2009, warned that regional climate change was speeding the surge of the majority of Pakistan’s 5,218 glaciers, which cover an area of 15,000 square kilometers. These studies predicted an increase in water by sub-glacial lake outbursts over a short period of time.
Additionally, an increasingly variable summer Indian monsoon pattern now brings large rainfall variability. This pattern may bring fewer rainy days, and an increase in short and intense periods of rainfall. However, the overall result is that, while there is an overall decrease in the amount of rainfall, there is also an increase in both drought and flood conditions.
The flooding of the Northwest, Punjab and Sind provinces of Pakistan have been further exacerbated by the siltation of major reservoirs, such as the Tarbela on the Indus, and the Mangla on the Jhelum, as well as other small barrages and reservoirs. Himalayan water has been charged with huge suspended sediment loads over the years-indeed, even in normal times, Pakistan has had problems managing the extra water, heavily-silted water flowing in its rivers.
The observed erratic timing and intensity of the regional monsoon and westerly systems have created serious hazards for Pakistan, and displaced more than 20 million people by inundating more than 125,000 square miles of land with floodwater. Policymakers in the region now have to begin effectively planning adaptation strategies for this uptick in extreme weather.
The case is not hopeless. We now have a better understanding of the rate at which water availability in the Himalayan ecosystem is changing. Remote sensing and real time data sets are revealing the relative proportions of water coming from different sources, namely melting glaciers, snow, and rainfall. Decision makers should support better regional and global climate analyses and predictions. This requires more detailed ground observation networks and detailed modeling, which can help scientists and policymakers better predict extreme weather events.
The impact of the 21st century’s glacier melt on the region’s water resources can be estimated by scenario models that use recent satellite observations to simulate changes in temperature and precipitation. These models can produce quantitative estimations of the percentage of water in the major river basins which originates from glacier melt.
NASA’s satellite remote sensing products derive models for glacier mass balance and surface hydrology, and can be instrumental in helping to correctly understand the region’s hydrology. However, NASA’s satellite observations and in-situ forcing of snow and ice melt modeling must be verified by using data sets collected on benchmark glaciers by Pakistani, Indian, Afghani, and Chinese scientists.
The US commitment in south Asia deepened in 2010 by bringing both India and Pakistan in its strategic and security framework. Climate change, growing populations, intensification of water use, and general non-cooperation over shared water resources puts the region as a threat to global and regional security.
The affects of changes in water availability necessitates trans-boundary coordination and cooperation between countries. It is only through such coordination that the policymakers can obtain a holistic perspective of the ongoing changes to anticipate and prevent a subsequent disaster.
Photo Credit: Glaciers in India, 2008
Map Credit: Adapted from the report: Himalayan Glaciers, Climate Change and Water Security in South Asia Synthesis Report, The US Foreign Service Institute. November 17, 2009, p.2