NOAA: CO2, methane concentrations grew in 2008

Atmospheric concentrations of two major greenhouse gases increased last year, the National Oceanic and Atmospheric Administration said.

Nick Snow
OGJ Washington Editor

WASHINGTON, DC, Apr. 22 -- Atmospheric concentrations of two major greenhouse gases increased last year, the National Oceanic and Atmospheric Administration said.

NOAA said a preliminary analysis of the US Department of Commerce agency's annual GHG index, which tracks data from 60 sites around the world, found an additional 16.2 billion tons of carbon dioxide and 12.2 million tons of methane in the atmosphere at the end of December.

The increase occurred despite a global economic recession late in the year that decreased a wide range of activities that use fossil fuels, NOAA said.

The agency released its report as the US House Energy and Commerce Committee's Energy and Environment Subcommittee began several days of hearings on a proposed cap-and-trade system. Four days earlier, the US Environmental Protection Agency said in a proposed endangerment finding that greenhouse gases threaten public health.

"Only by reducing our dependence on fossil fuels and increasing energy production from renewable resources will we start to see improvements and begin to lessen the effects of climate change," said Pieter Tans, a scientist at NOAA's Earth System Research Laboratory in Boulder, Colo.

Tans said that, viewed another way, for every million molecules of air, another 2.1 molecules of CO2 entered the atmosphere last year and stayed there, slightly less than 2007's 2.2 ppm increase. Total global concentrations topped 386 ppm, compared to 280 ppm before the Industrial Revolution began in the 19th century, Tans said.

Increases in CO2 and methane during 2008 were slightly less than those measured in 2007, but fell within the range of yearly fluctuations from natural changes, according to NOAA experts.

They said that data show that methane levels rose for a second consecutive year in 2008 after a 10-year lull. Atmospheric concentrations increased by 4.4 molecules for every billion molecules of air, bringing the total global concentration to 1,788 ppb, they indicated.

Pound for pound, methane is 25 times more potent as a GHG than CO2, but there's far less of it in the atmosphere, and it is measured in ppb instead of ppm, NOAA said. When related climate effects are taken into account, methane's overall climate impact is nearly half of CO2's, it added.

Contact Nick Snow at nicks@pennwell.com.

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