"We've entered an age in which the production of energy, especially from fossil fuels, demands ever-more-expensive environmental trade-offs. We've entered what Michael Klare, professor at Hampshire College, calls the era of "extreme energy." Consider how oil production in the United States has evolved. In Texas in 1901, wildcatters didn't have to work very hard to tap into the great Beaumont gusher. The oil was essentially at the surface, all but seeping out of the earth's crust. When the land-based oil was exhausted, American prospectors went to sea. And when the shallow-water oil was exhausted, they went farther out. In 1985, only 21 million barrels, or 6 percent of the oil produced in the Gulf of Mexico, came from wells drilled in water more than 1,000 feet deep. In 2009, such wells produced 456 million barrels, or 80 percent of total Gulf production. Today, deep-water Gulf wells account for about one-quarter of the oil the United States sucks from the earth."