Barack Obama is the 44th president of the United States. Regarding the environment, President Obama's platform has involved major policy to dramatically reduce the nation's energy use and create green jobs. Congress has wrestled with a climate change bill that is still making its way through the legislative process. Its goal is to reduce U.S. emissions of greenhouse gases using a cap-and-trade system that sets a limit on overall emissions of heat-trapping gases while allowing emitters to trade pollution permits or credits. (Source: New York Times, Barackobama.com / Photo: Flickr)