WASHINGTON -- The amount of heat-trapping carbon dioxide in the air jumped dramatically in 2012, making it very unlikely that global warming can be limited to another 2 degrees as many global leaders have hoped, new federal figures show.
Scientists say the rise in CO2 reflects the world's economy revving up and burning more fossil fuels, especially in China.
Carbon dioxide levels jumped by 2.67 parts per million since 2011 to total just under 395 parts per million, says Pieter Tans, who leads the greenhouse gas measurement team for the National Oceanic and Atmospheric Administration.
That's the second highest rise in carbon emissions since record-keeping began in 1959. The measurements are taken from air samples captured away from civilization near a volcano in Mauna Loa, Hawaii.
More coal-burning power plants, especially in the developing world, are the main reason emissions keep going up -- even as they have declined in the U.S. and other places, in part through conservation and cleaner energy.
At the same time, plants and the world's oceans which normally absorb some carbon dioxide, last year took in less than they do on average, says John Reilly, co-director of Joint Program on the Science and Policy of Global Change. Plant and ocean absorption of carbon varies naturally year to year.
But, Tans told The Associated Press the major factor is ever-rising fossil fuel burning: "It's just a testament to human influence being dominant."