Bill McKibben plays a vital role in the environmental movement. As an activist, and thinker, his contributions have international significance.
2012 - a year marked by droughts, brushfires, and crop damage, was the hottest year on record for the lower 48 U.S. states.
One hundred and thirty fires blazed across New South Wales, Australia's most heavily populated state, as emergency teams evacuated national parks and fought to get the flames under control.
There may not yet be the political will in Congress to pass significant climate change legislation. But efforts to address this issue will continue to get strong support from Mother Nature.