Tuesday, September 27, 2011

The problem with dams

Peter Bosshard, director of International Rivers, in Common Dreams: When the World Commission on Dams reviewed the development effectiveness of dams, multipurpose projects with large dams, power plants and irrigation schemes had the worst social, environmental and economic track record. As the world is grappling for appropriate answers to climate change, influential actors such as the World Bank want to give these complex schemes a second chance. They are wrong. While we need to integrate the concerns of climate change, water, energy and food security, we don’t need to go back to old-fashioned multipurpose schemes like the Narmada dams. And while we need to store water to adapt to a changing climate, we can do so in other ways than the big, centralized reservoirs of the past.

Large dams and reservoirs are not well-suited to a changing climate for two reasons. First, the arteries of our planet are already suffering from a higher rate of species extinction than any other major ecosystem. Climate change will compound the pressure on vital freshwater resources, and will make projects with large ecological footprints unaffordable. Secondly, big reservoirs cannot respond flexibly to the rapid shifts in streamflows that climate change brings about. Dams that reflect past hydrological patterns may become unsafe as storms intensify, and uneconomic as droughts become more frequent.

Climate change has already begun affecting the world’s rivers and dams. Only last month, Bhutan’s Prime Minister Jigmi Thinley warned: “The climate is changing, global warming is real and the impact on our hydrology is very severe… Hydropower may not be the sort of exponential source that we considered it to be.” Countries like Tanzania are suffering frequent brownouts because they depend on hydropower projects that are ill-matched with today’s climate. A new paper in the scientific journal, PLoS Biology, found that “particularly for large [water] infrastructure projects, the risks for investors, communities, and ecosystems are extremely high given uncertainties in future hydrological conditions”. It concluded that “climate-infrastructure mismatches may make poor nations even poorer”....

Gordon Dam, Southwest National Park, Tasmania, Australia. Shot by Noodle snacks, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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