The Jinsha River tumbles down from the highlands of the Tibetan Plateau and courses through China for more than 1,300 miles (2,900km) before becoming the Yangtze. Until recently, it was a free-flowing waterway that ran through the picturesque landscape of Yunnan and Sichuan Provinces, but that is changing rapidly. Taking advantage of a drop of nearly 14 feet per mile, the Chinese government is building - or planning to build - as many as 12 large dams on the Jinsha. More than 300,000 people will be displaced, numerous cultural sites will be flooded, and river ecosystems irretrievably altered.
The Jinsha’s fate is typical of many of China’s rivers, as the country is engaged in a frenzy of dam building that has left it with more dams - 26,000 at last count -than any other nation in the world. In the past two decades, hundreds have been built for hydropower production, enabling towns like Shigu - famed in China as the site at which Mao and the Red Army crossed the Jinsha as part of the Long March - to leap forward from backwaters to regional centres.
“We wish to have a better life but still live in beautiful nature,” Cun Yanfang, who was born and raised in a village on the mountainous banks of the Jinsha, told me on a recent trip to China.
In China - and throughout the developing world - that is proving to be an increasingly difficult balance to strike. What is happening along the Jinsha, the Yangtze, and dozens of other Chinese rivers is emblematic of a major resurgence of dam building worldwide - a trend that is likely to intensify as growing concerns about global warming make hydropower look more appealing.
The rapid rate of dam construction today is akin to a form of environmental and social triage, with the need for a renewable, carbon-free source of electricity taking precedence over the rights of displaced local populations and the preservation of river ecosystems. As a result, governments, the World Bank, and even some environmental groups are embracing dam construction, some with an enthusiasm not seen since the heyday of industrial dam building last century when mammoth hydropower projects - from the Hoover Dam in the United States to the High Aswan Dam in Egypt - were built.
From Brazil - where large dams have been built or are planned along the Amazon River and its tributaries - to Mozambique, India, and Laos, hydroelectric power stations are being constructed at a furious pace. The World Commission on Dams reports there are now 48,000 dams taller than 50 feet (15.4m) worldwide. Hydropower stations currently under construction around the globe will, when finished, produce 151 gigawatts of electricity - the equivalent of several thousand large, coal-fired power plants. That represents nearly 20 per cent of electricity being generated by all the hydropower projects ever constructed.
Given the threat of global warming and the essential nature of electricity to development, the arguments for erecting dams seem strong. China’s Three Gorges Dam - built from 1994 to 2008 - produces electricity equivalent to 500 large coal-fired power plants, more than any hydropower station in the world. That output avoids the production of at least 95 million metric tons of carbon dioxide, or roughly the emissions of Norway and Sweden combined. Even Greenpeace China has called for more hydropower development (with appropriate environmental safeguards) in its "Energy [R]Evolution" plan to produce half of China’s energy needs from renewables.
Yet this surge of dam building has come at enormous human, environmental, and cultural costs. Three Gorges Dam has displaced 1.2 million people. In recent decades, Brazil has built four large dams in its Amazon basin and is planning as many as 70 more, including two on the main tributary to the Amazon River, the Madeira. These two huge dams would displace thousands of indigenous families, flood large areas of rainforest, and alter the river so extensively that the migration of 750 species of fish would be affected, according to the dam watchdog group International Rivers.
Recent studies also have indicated that the 320 million tons of water in the reservoir behind the newly constructed Zipingpu Dam in China’s Sichuan Province might have triggered last May’s devastating earthquake by placing stress on a major fault line less than a mile away. More than 70,000 people died in that disaster.
China outpaces all other dam building nations: in the last decade, more than 60 per cent of the hydropower projects completed worldwide have been in China.
“You can see and hear rational arguments from the Chinese: climate, air pollution, diversify [energy] supply,” says Patrick McCully, executive director of International Rivers, based in Berkeley, California. “On the ground, it’s basically unregulated with companies trying to build as much as possible as fast as possible … China’s just devastating its rivers and displacing millions of people. If they are going to build hydro, then they should do it in a rational, well-planned way so that it’s only the less destructive projects that get built and they get built with more safeguards for affected people.”
Dam building creates other significant impacts as well. Drowned trees and vegetation burp methane - which traps heat at 25 times the rate of CO2 - out of the reservoirs, particularly in tropical regions like Brazil. In fact, scientists at Brazil’s National Institute for Space Research calculate that the world’s large dams are responsible for producing 104 million metric tons of methane a year - making dams the single largest source of human-caused methane.