Here’s the latest from Lester Brown and the Earth Policy Institute:

Between 2007 and 2011, carbon emissions from coal use in the United States dropped 10 percent. During the same period, emissions from oil use dropped 11 percent. In contrast, carbon emissions from natural gas use increased by 6 percent. The net effect of these trends was that U.S. carbon emissions dropped 7 percent in four years. And this is only the beginning.

The initial fall in coal and oil use was triggered by the economic downturn, but now powerful new forces are reducing the use of both. For coal, the dominant force is the Beyond Coal campaign, an impressive national effort coordinated by the Sierra Club involving hundreds of local groups that oppose coal because of its effects on human health.

And here’s more:

In August, the American Economic Review—the country’s most prestigious economics journal—published an article that can only be described as an epitaph for the coal industry. The authors conclude that the economic damage caused by air pollutants from coal burning exceeds the value of the electricity produced by coal-fired power plants. Coal fails the cost-benefit analysis even before the costs of climate change are tallied.

They also report:

Even as coal plants are closing, the use of wind, solar, and geothermally generated electricity is growing fast. Over the last four years, more than 400 wind farms—with a total generating capacity of 27,000 megawatts—have come online, enough to supply 8 million homes with electricity. (See data.) Nearly 300,000 megawatts of proposed wind projects are in the pipeline awaiting access to the grid.

They conclude:

With emissions from coal burning heading for a free fall as plants are closed, and those from oil use also falling fast—both are falling faster than emissions from natural gas are ramping up—U.S. carbon emissions are falling.

We are now looking at a situation where the 7 percent decline in carbon emissions since the 2007 peak could expand to 20 percent by 2020, and possibly even to 30 percent. If so, the United States could become a world leader in cutting carbon emissions and stabilizing climate.