Unaware of risks

More than 150,000 megawatts (MW) of new hydropower is proposed to be built in the next 20 years in the four countries. At that rate, the Himalaya could become the most heavily dammed region in the world. Some of these dams – including the Dibang project in India, the Tala project in Bhutan, and the $12.6 billion Diamer-Bhasha Dam in Pakistan – are among the world’s largest and most expensive planned dams.
Shockingly, this dam boom is not being analysed for the biggest threat to hydrological projects of our time: global warming. “The possible impacts of climate change are not being considered – neither for individual dams, nor cumulatively,” says Shripad Dharmadhikary, author of Mountains of Concrete: Dam Building in the Himalayas, a study published by International Rivers in December 2008.

A dam-building boom in the Himalayas in times of global warming is like investing billions of dollars in high-risk, non-performing assets in times of a financial crisis. In the Himalayas, “melting glacier water will replenish rivers in the short run, but as the resource diminishes, drought will dominate the river reaches in the long term,” says Xin Yuanhong. He is a senior engineer with a Chinese team that is studying the glaciers of the Tibetan plateau.

Both the initial increase in river flows as well as the subsequent decline threatens the safety and viability of the planned hydropower projects. Dharmadhikary points out: “Most dams are designed based on historical data of river flows, with the assumption that the pattern of flows will remain the same as in the past.” He says that climate change has effectively destroyed this assumption. “It is likely that dams will be subjected to much higher flows, raising concerns of dam safety, increased flooding and submergence, or much lower flows, affecting the performance of such large investments.”

The International Centre for Integrated Mountain Development, ICIMOD, in Nepal and the Intergovernmental Panel on Climate Change (IPCC) agree that global warming will not only lead to extremes such as minimum and maximum-recorded temperatures, but also lead to more storms and floods, especially in tropical and mountainous regions. A report by ICIMOD on the impact of climate change on Himalayan glaciers states: “On the Indian subcontinent, temperatures are predicted to rise between 3.5 and 5.5 degree Celsius by 2100.“ An even higher increase is predicted for the Tibetan Plateau.

Devastating lake bursts

The sudden bursting of glacial lakes is another major concern for the safety of planned dams, and ultimately the rivers and peoples of the Himalayas. Glacial lake outburst floods (GLOFs) are a recent phenomenon. As glaciers melt, they can form large lakes behind temporary dams of ice and rock. When these moraine dams collapse, millions of cubic meters of water are released, resulting in massive flash floods. The Dig Tsho GLOF in Nepal in 1985 was one of the most devastating glacial lake bursts in recent history. The bursting of this glacial lake near Mount Everest caused a huge flood wave that travelled down the valley, killing five people and destroying one hydropower station, 14 bridges and many acres of cultivated land.

In January 2009, the government of Bhutan identified more than 2,600 glacial lakes in the country, of which 25 are considered to be at high risk of bursting, according to Bhutan’s Department of Geology and Mines. While Bhutan is aware of the risk of GLOFs and is improving its early warning system, the country, together with India, is still currently constructing one of the largest hydropower dams in the region, the 90-meter-high Tala project on the Wangchu River.

One billion people in South Asia and many millions in China depend on the Himalayan rivers – for agriculture as well as for drinking water supplies. While we can't predict the future course of change to these lifelines from global warming, we can no longer presume that there will always be abundant snow and glaciers in the Himalayas, feeding Ganga, Indus und Bhramaputra with as much water as in the last 50 years.

While we can't predict the future course of change to these lifelines from global warming, we can no longer presume that there will always be abundant snow and glaciers in the Himalayas. If the Himalayan governments go forward with their planned dam boom, they deny that global warming is actually transforming their region and our planet.

Instead of denying global warning and planning outdated, expensive projects just as before, the prudent course would be for the Himalayan countries to develop water resources in a way that helps the people of the region adapt to the changing climate, and reduces their risks.