What's Happening & Why
Evidence from the top of the atmosphere to the depths of the oceans, collected by scientists and engineers from around the world, tells an unambiguous story: the planet is warming, and over the last half century, this warming has been driven primarily by human activity—predominantly the burning of fossil fuels.
U.S. average temperature has increased by 1.3°F to 1.9°F since 1895, and most of this increase has occurred since 1970. The most recent decade was the Nation’s and the world’s hottest ever recorded, and 2012 was the hottest year on record in the continental United States. Temperatures are projected to rise another 2°F to 4°F in most areas of the U.S. over the next few decades.