The World Meteorological Organization said 2012 was the ninth warmest year on record despite a cooling La Nina weather pattern earlier in the year. It also marked the 27th consecutive year that global temperatures were higher than the 1961-90 average.
A study from the U.S. Geological Survey found snowpack in the Rocky Mountains, starting in the 1980s, is starting earlier in the year. A new study links temperature patterns to 30-year snowpack declines.
Runoff from the Rockies accounts for around 70 percent of the water supply for western U.S. residents and the timing affects everything from hydroelectric dams to flooding and wildfires.
The U.S. Interior Department said the risk of fires for western states is above average for 2013. There have been more than 600 wildfires reported this year in California. The Interior Department said more than 9 million acres of land burned in wildfires last year.