The U.S. Geological Survey has recorded seven small earthquakes shaking central Oklahoma in a span of about 14 hours.
Four administrators of the U.S. Environmental Protection Agency who served under Republican presidents told a Senate panel Wednesday that climate change is real and the federal government has the responsibility and the legal authority to combat it.
State officials are evacuating fish from hatcheries on the American River because of the drought. Water temperatures are expected to become too warm to keep the fish alive in coming weeks.
Hydraulic fracturing or fracking is a method of extracting oil and gas that are inaccessible by conventional drilling. Fracking has become increasinly common over the past decade and accounts for a large proportion of oil and gas production in the United States. Fracking involves freeing the gas or oil trapped in non-permeable layers of shale by fracturing the layer, thus freeing up the gas or oil. Click the button to begin the process:
Today, California's Sierra Nevada - one of the world's great mountain ranges - is suffering a slow death. Almost everywhere there are problems: polluted air, dying forests, poisoned rivers, vanishing wildlife, eroding soil and rapid-fire development. Even Muir's holy ground, Yosemite National Park, is hurting: Much of its forest has been damaged by ozone.