October 12th, 2010
(The article below has been adapted from Chapter 2, “Population Pressure: Land and Water,” in Lester R. Brown’s book Plan B 4.0: Mobilizing to Save Civilization (New York: W.W. Norton & Company, 2009). Brown is the president of the Earth Policy Institute.)
The thin layer of topsoil that covers the planet’s land surface is the foundation of civilization. This soil, typically 6 inches or so deep, was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. But sometime within the last century, as human and livestock populations expanded, soil erosion began to exceed new soil formation over large areas.