The amount of harmful greenhouse gas pollution spewed into the atmosphere by large U.S. power plants has declined 10 percent since 2010, the Obama administration said Wednesday.
The results came from the third year of carbon pollution emissions data that the Environmental Protection Agency (EPA) collects from nearly 8,000 facilities including power plants, oil refineries and steel mills.
In all, these operations, which make up 85 to 90 percent of total U.S. greenhouse gas production, reported direct carbon emissions of 3.13 billion metric tons in 2012.
The decline in power plant emissions is "due to a switch from coal to natural gas for electricity generation and a slight decrease in electricity production," the EPA said in a statement.
The decline from 2011 to 2012 was 4.5 percent, it added.
"Fossil-fuel fired power plants remain the largest source of US greenhouse gas emissions," said the EPA, noting that just under 1,600 facilities had emitted over 2 billion metric tons of carbon dioxide, or 40 percent of the U.S. total, in 2012.
The EPA mandate to report on greenhouse gases from U.S. sources that emit 25,000 metric tons or more of carbon dioxide per year began under President Barack Obama in 2009.
In June, the Obama administration set strict limits for carbon pollution generated by any newly constructed power plants. The focus on greenhouse gas emissions comes as Obama continues to weigh whether to greenlight the controversial Keystone XL pipeline, which would carry carbon-intensive tar sands oil from Canada to refineries in Texas. The president has said he will approve the pipeline only if its construction would not result in a net increase in the climate-warming gases.
The EPA report mirrors a study on global emissions released Wednesday, which shows that the rate of increase of carbon dioxide emissions waned in 2012.
Global carbon emissions last year increased at less than half the average seen in the past decade, fueled by the U.S. shift to shale gas for energy and China’s increased use of hydropower, according to a report by PBL Netherlands Environmental Assessment Agency.
Although global emissions of carbon dioxide reached a new record of 34.5 billion metric tons in 2012, the increase slowed down to 1.1 percent, the report shows. The average annual increase over the last decade was 2.9 percent.
China, the U.S. and the European Union account for 55 percent of total global emissions. But China, which in the past decade saw annual emissions increases of roughly 10 percent, increased its carbon emissions by only 3 percent in 2012.
The end of China’s economic stimulus package, intended to avoid a fall in annual growth during the global recession, helped the Asian nation reduce its emissions last year, the report notes.
"They want to grow economically less fast," Greet Maenhout, a co-author of the report, told BBC News.
Al Jazeera and wire services