CO2 in air grows fast: study

"Atmospheric carbon dioxide growth has increased 35 percent faster than expected since 2000," said a statement from the British Antarctic Survey (BAS), one of the bodies involved in the research.

Inefficient use of fuels increased CO2 by 17 percent, while the other 18 percent was due to a decline in the efficiency of natural "sinks," the forests and seas that soak up the gas from the atmosphere, it said.

"Fifty years ago, for every tonne of CO2 emitted, 600 kilograms (1,300 pounds) were removed by natural sinks. In 2006 only 550 kilograms were removed per tonne and that amount is falling," said the study`s lead author, Pep Canadell of the Global Carbon Project, in a statement.