The Environmental Protection Agency has released the second year of dataof the nation's greenhouse gas emissions, which it's congressionally-mandated to report.Greenhouse gases include carbon dioxide, methane and nitrous oxide, and are thought to be one of the primary drivers of climate change. The EPA has successfully argued that the gases are pollutants and pose a danger to human health.The 2011 data shows that power plants are responsible for about one-third of the total greenhouse gas emissions in the U.S: the equivalent of 2,221 million metric tons of carbon dioxide. But that number has gone down about 4.6 percent since the 2010 figures.In Kentucky, power plants emitted 93 million metric tons of the gases. This made up about 77 percent of the state's total greenhouse gas emissions. In Jefferson County, there were more than 18 million metric tons emitted, and power plants accounted for 65 percent of that. The chemical industry came in second, with 26 percent.The data for Jefferson County shows little change from 2010; the releases dropped by only about 63,000 tons. Power plants, the metals industry and the minerals industry reduced their emissions slightly between the two years. But the "petroleum and natural gas systems" category more than doubled its emissions, and there was also an increase in the greenhouse gas emissions from the chemical industry.The Natural Resources Defense Council responded to the new set of data by calling for stricter regulations on greenhouse gas emissions. From David Doniger, policy director for the Natural Resources Defense Council’s Climate and Clean Air Program:
