Wednesday, April 30, 2008

Methane, a greenhouse gas, rises ‘sharply’ for the first time in a decade; CO2 is up too


(Photo of Arctic marshes and tundra from Flickr and photographer Royal Olive/G. Oliviera)

News Update: Methane in the atmosphere rose last year for the first time since 1998, according to the National Oceanic and Atmospheric Administration, which monitors such things. Methane is a concern because it’s 25 times more potent than carbon dioxide as a heat-trapping gas, though there’s much less of it in the atmosphere. The increase last year was 27 million tons. NOAA speculated that it’s probably coming from the economic boom in Asia and from wetlands uncovered by melting ice in the Arctic and also in the tropics. The main worry about methane is that thawing permafrost in the Arctic will release huge amounts of it. NOAA also announced that CO2 rose 2.4 parts per million last year, to 385 ppm. That compares with 280 until the mid-19th century. A safe level is between 350-450 ppm, depending on who you ask. In the ’60s the annual increase was 1 ppm, in the ‘80s 1.5 ppm, and since 2000 about 2 ppm each year. So last year’s jump may show it’s going to another level. CO2, we know, comes primarily from the burning of fossil fuels. For more, and a chart of recent annual CO2 growth, see Science Daily.)

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