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Dams for Patagonia

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Science  23 Jul 2010:
Vol. 329, Issue 5990, pp. 382-385
DOI: 10.1126/science.329.5990.382

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The Southern Ice Field in Patagonia is the world's third most important reserve of freshwater after Antarctica and Greenland. And in its untamed wilderness of glaciers and mountain peaks, companies are preparing to build at least seven major hydropower dams, along with a 70-meter-high transmission line to transport power more than 2400 kilometers north to Santiago, Chile's capital, and the energy-hungry mines beyond. The line would require one of the world's biggest clear-cuts, a 120-meter-wide corridor through ancient forests—fragmenting ecosystems—and the installation of more than 5000 transmission towers. Proponents of the dams argue that hydroelectricity is a clean source of energy, that Chile needs the 3500 MW/yr of power to meet its development goals and, lacking oil or coal reserves, has no viable alternative (see sidebar). But more than 50 international environmental groups have come together to try to block dam construction. So unpopular are the construction schemes that Chile's second biggest bank, BBVA, announced in January that it would not be assisting the power company, HidroAysén, with loans for hydroprojects, citing environmental and social concerns. The controversy raises questions about the goals of economic development and about the definition of environmentally clean energy—issues that divide the entire nation.