World carbon dioxide pollution levels in the atmosphere are accelerating and reached a record high in 2012, the U.N. weather agency said Wednesday.
The heat-trapping gas, pumped into the air by cars and smokestacks, was measured at 393.1 parts per million last year, up 2.2 ppm from the previous year, said the Geneva-based World Meteorological Organization in its annual greenhouse gas inventory.
As the chief gas blamed for global warming, carbon dioxide’s 2012 increase outpaced the past decade’s average annual increase of 2.02 ppm.
Based on that rate, the organization says the world’s carbon dioxide pollution level is expected to cross the 400 ppm threshold by 2016. That level already was reached at some individual measurement stations in 2012 and 2013.
Scientists say the Earth probably last had this much carbon dioxide in the atmosphere at least a few million years ago, when sea levels were higher. Carbon dioxide levels were around 280 ppm before the Industrial Revolution.