THE GREAT HIMALAYAN WATERSHED

Agrarian Crisis, Mega-Dams and the Environment

For almost half the world’s population, water-related dreams and fears intersect in the Himalayas and on the Tibetan plateau. Other regions have their share of conflicting claims over water issues: Turkey, Syria and Iraq over the headwaters of the Tigris; Israel and its neighbours around the Jordan basin; the us and Mexico over the Colorado River; the riparian states of the Paraguay, the Parana or the Nile. But none combine the same scale of population, scarcity of rainfall, dependence on agriculture, scope for mega-dam projects and vulnerability to climate change as those at stake within the greater Himalayan region. Here, glaciers and annual snowmelts feed rivers serving just under half of the world’s population, while the unequalled heights from which their waters descend could provide vast amounts of hydro-power. At the same time, both India and China face the grim reality that their economic and social achievements since the late 1940s—both ‘planned’ and ‘market-based’—have depended on unsustainable rates of groundwater extraction; hundreds of millions of people now face devastating shortages.
A World Bank study of India’s water future argues that the Himalayas offer one of the world’s ‘most benign environments’ for dam-building. The basis of this estimate is simple: a calculation of people to be displaced and acreage to be submerged per megawatt generated. [53] Given the huge power potential in the denominators of these projects and the sparse population of many highland areas, these ratios are not surprising, and they deserve to be taken seriously. But they are by no means a complete measure of the costs and risks involved. Like all dams, those planned for the Indian Himalayas would submerge significant amounts of land, including forests and grazing areas important to a number of the remaining migratory people in the region. Several involve diverting rivers through underground tunnels which would create large dry regions, with serious impacts on local fisheries and farming. Moreover, the Himalayas represent a major—and fragile—concentration of biodiversity. Their rapid rise, from 500 metres to over 8,000 metres, creates a remarkable range of ecosystems within a relatively small space. Conservation International reports that, of an estimated 10,000 plant species in one Himalayan sub-region, over 3,100 are found nowhere else. [54] And here, too, as in Tibet and Yunnan, there are significant risks of earthquakes and glacial lake outbreak-floods.

Perhaps most surprising, it is no longer clear that large hydro-dams are even a consistently climate-friendly source of energy. While hydro-electricity can be a substitute for carbon-dioxide producing fossil fuels, the reservoirs behind big dams often include large amounts of rotting vegetable matter and thus are a significant source of methane—a much more potent greenhouse gas. (This is not an issue for ‘run of the river’ dams, which have no reservoirs; but these make up a very small percentage of big projects.) These methane emissions are larger in tropical and sub-tropical climates, where vegetation both grows and decays faster. A 2007 study suggested that methane from dam reservoirs actually accounted for 19 per cent of India’s greenhouse-gas emissions, while hydro-power accounts for only 16 per cent of the country’s electricity and less still of its total energy use. [55] These figures are still preliminary estimates; methane emissions may be lower than average for dams high in the Himalayas, which is not an area where plant matter grows or decays rapidly; and there may be ways to mitigate these effects, by capturing and burning the methane to generate more power. But they call into question the common assumption that, despite the environmental risks, large dams are a ‘greener’ energy source than most alternatives; the non-trivial greenhouse emissions involved in creating huge amounts of concrete and steel further complicate the picture.

Further east, the plans are not quite as ambitious, but they still portend dramatic changes for millions of people. Those affecting the Salween River—known as the Nu in eastern Tibet and Yunnan—are shrouded in the greatest mystery, since for most of its length it is either in China or Burma, in places forming the Burmese-Thai border; neither regime welcomes publicity. Because the Salween still runs within steep mountain gorges for many miles after crossing into Burma, before dropping quite suddenly just before reaching its delta, there is enormous hydro potential here, and much less domestic demand. To date, the Salween has not been tapped very much for human use; it remains one of the few large free-flowing rivers left in Asia. A major dam on the Chinese side of the border was stopped in 2004 for environmental reasons, and work has recently been suspended again. However, there are now a number of dams planned or underway on the river, both in China—where the maximum programme calls for a ‘staircase’ of thirteen dams—and in Burma. [56] The expectation is that the power generated in Burma will be exported to Thailand, Vietnam and perhaps China.

An extensive report from New Left Review