The dam building boom: right path to clean energy?

“Within the last four years, the water is less than we expect,” Chongqing’s Lai says. “This is really a big problem for us.”

The environmental effects are already being felt in China. Stretches of the Jinsha River - “Golden Sands” in English - run red as the iron-rich dirt removed to build these dams is dumped back into the river. Already, thanks to Three Gorges and other dams, the nutrient mix in the East China Sea, where the Yangtze empties, has changed dramatically as less water and silt reach the sea.

Another sign of hydropower’s resurgence is the World Bank’s decision to once again get more deeply involved in the business of funding dams. Once strongly criticised for backing massive dam projects that displaced millions and harmed the environment, the bank has announced plans to increase lending to hydropower as part of its commitment to fund renewable energy projects. The bank’s dam funding will rise to $1.3 billion in fiscal year 2011, up from $800 million in 2008.

The resurgence of dam building has slowed somewhat in recent months, due to the global economic crisis. But few think the slowdown will be anything but temporary, according to International Rivers' McCully.

For its part, China is relying on such massive infrastructure projects as part of its 4 trillion yuan ($585 billion) economic stimulus program. If such projects can gain additional credence by acquiring the patina of combating climate change, all the better. China has applied for at least 729 new dams to receive carbon credits under the terms of the Kyoto Protocol - more than half the global total of such hydroelectric project applications.

“This is a huge scam,” McCully argues. “Three-quarters of them are already built when they go for carbon credits. It’s hard to argue that they need the carbon credits to get built.”

The decision to construct dams has always presented governments with the dilemma of balancing economic development with the rights of local populations and environmental protection. For the most part, development has trumped other concerns.

Now, with dam proponents arguing that hydropower meets the most pressing environmental need of our time - reducing greenhouse gas emissions - opposing dam construction has become doubly difficult.

“Over the short and medium term, dams remain an important development option under certain conditions,” says Scudder. “Over the long run, large dams are unsustainable development.”