Strong scientific evidence shows that climate change is producing hotter, drier conditions that contribute to larger fires and longer fire seasons in the American West today. The annual number of large wildfires on federally managed lands in the 11 western states has increased by more than 75 percent: from approximately 140 during the period 1980-1989 to 250 in the 2000-2009 period. The western wildfire season has grown from five months on average in the 1970s to seven months today. Moreover, the threat of wildfires is projected to worsen over time as rising temperatures-rising more rapidly in the American West than the global average-continue to lead to more frequent, large, and severe wildfires and longer fire seasons.