NCPA - National Center for Policy Analysis

Dammed Rivers: Do Or Don't?

December 7, 2000

At first glance, hydroelectric power from big dams appears to be a greener way to generate electricity than burning fossil fuels. But an organization called "The World Commission on Dams" has concluded that dams' impact on eco-systems are "mostly negative" -- results announced by no less than Nelson Mandela.

According to the commission, which is backed by the World Bank and industry:

  • Dam construction projects destroy habitat, reservoirs cover forest and farmland and downstream land is deprived of water and nutrients.
  • Moreover, rotting vegetation trapped in reservoirs emits methane and carbon dioxide.
  • Some estimates put the contribution of gases emitted by manmade reservoirs at more than one-quarter of the world's "global-warming potential."

And although dams make valuable economic contributions, projects have been undertaken for purposes of national pride -- rather than electrical demand -- and thus some have proved unprofitable, slow to deliver energy or water, and prone to corruption.

  • The commission estimates that the world contains 45,000 large dams, with nearly half the world's rivers having at least one.
  • One-third of countries depend on hydropower for over half their electricity.
  • Over one-third of the world's irrigated land depends on dams.
  • The cheap irrigation water subsidizes much of the world's food.

Some 80 million people have been displaced by dams, mostly through government force, and over $2 trillion has been invested in them.

That leaves experts to theorize that it might have been better to create electricity by burning gas, oil or even coal.

Source: "A Barrage of Criticism," Economist, November 18, 2000.

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