Since time immemorial, the rivers that rise in the Himalayan mountains have played a vital role in the economies of the countries through which they run. The glaciers that feed them are natural reservoirs or buffer tanks. The water they accumulate during the winter enables the growth of crops and plants downstream in the summer.
However, global warming is contributing to a rapid melting of the Himalayan glaciers. Between 1970 and 2000, 9% of their ice volume was lost (1). In the period from 2003 to 2009, they lost about 170 gigatons of water often leading to catastrophic flooding throughout the Indus, the Ganges and the Brahmaputra regions. In the spring of 2010 for example, heavy rains combined with a premature thaw which led to one fifth of the surface area of Pakistan being under water for nearly five weeks; the cost of the damage ran to several tens of billions of dollars (1).
The new trend is for more rain than snow, especially in spring. As a result the snows melt earlier leading to raging torrents in spring; while in the summer, that’s to say at the time when crops are in their phase of strongest growth, volumes of water in the streams and rivers are reduced. As a consequence, agricultural yields are lower, arid zones expand and fishing suffers. Ultimately, the consequence will probably be the displacement of populations.
The melting of the Himalayan glaciers will also affect river flows downstream, the volume of water in dams and the level of their electricity production. Some rivers will be more affected than others by this phenomenon, although we do not yet know how to measure the scope of the effects. We do know that a decrease of 1 % in hydraulic flow results in a drop in electricity production of about 3%. However, the region has experienced chronic instability since the end of World War II, marked by recurrent clashes between the three dominant powers; China, India and Pakistan. The scale of changes in river flows crossing these countries risk undermining the fragile balance that prevails today, at a time when energy supply is vital to their economic and industrial development.
As the severe drought in California over the last four years seems to show, global warming leaves a deep footprint on ecosystems and beyond them, on the economies of the countries or regions where it strikes. No country today can claim to be protected. Those that are able to take adequate action in time to guard against its detrimental, even unpredictable effects, will be the big winners in this unimaginable struggle.
However, beyond the measures relevant only to national governments, links of cooperation between countries will have to be forged and strengthened. This is particularly the case for those countries which the Himalayan rivers traverse. In an ideal world these countries would ignore their historical differences to achieve a “win-win” strategy, thereby mitigating the effects of climate change and distributing equitably the burden it entails.
Undoubtedly, climate change goes beyond these regional concerns. It concerns the entire planet. Today it is possible to participate in this struggle through investments in environmental funds. In addition to their obvious utility, we expect these funds to generate superior performance given the huge needs that are becoming apparent.
(1) Yao, T. et al. Nature Clim. Chang. 2, 663–667 (2012)