China was the first to be named in 2007 and still leads that list as the most dammed nation in the world. The United States is second, followed by India, japan, Spain and Canada. In 140 countries, 47,
665 large dams exist. Scientists believe that the weight of their water alters the speed of the Earth’s rotation. Outside Magazine reports that one-fifth of the world’s electricity is generated from them, providing beneficial irrigation for one-sixth of the world’s food supply. During the construction of hydro-electric dams, 80 million people have been displaced. Experts also believe that dams inhibit fish migration and alter water flow in addition to adjusting temperatures. In recent years more than 212 dams have been torn down.