CO2, Methane Up Sharply In 2007

April 27, 2008

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The 2007 rise in global carbon dioxide concentrations is tied with 2005 as the third highest since atmospheric measurements began in 1958.

Global levels of atmospheric carbon dioxide, the primary driver of global climate change, increased by 0.6 percent, or 19 billion tons last year, the National Oceanic and Atmospheric Administration reports.

Additionally methane rose by 27 million tons after nearly a decade with little or no increase. NOAA scientists released these and other preliminary findings as part of an annual update to the agency’s greenhouse gas index, which tracks data from 60 sites around the world.

The rate of increase in carbon dioxide concentrations accelerated over recent decades along with fossil fuel emissions. Since 2000, annual increases of two ppm or more have been common, compared with 1.5 ppm per year in the 1980s and less than one ppm per year during the 1960s.

Methane levels rose last year for the first time since 1998. Methane is 25 times more potent as a greenhouse gas than carbon dioxide, but there’s far less of it in the atmosphere-about 1,800 parts per billion. Methane’s overall climate impact is nearly half that of carbon dioxide, according to NOAA.

Rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics are the most likely causes of the recent methane increase, said scientist Ed Dlugokencky from NOAA’s Earth System Research Laboratory.

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