The environmental impact of "fracking," the drilling technology largely responsible for America's boom in oil and gas production, are hotly contested. Consequences like water contamination have been established, but often it is not clear if they were directly caused by fracking or the result of sloppy drilling practices.» Read More
Brent crude futures rose as Russia threatened new actions in Ukraine.
The big environmental argument for nuclear energy: Its carbon emissions are the lowest among major power sources.
Warning Russia that new sanctions are "teed up," President Obama accused Moscow of failing to live up to an agreement to ease tensions in Ukraine.