[THS] Greenhouse Gases Rise Sharply in 2007

[Peter Webster]

http://www.truthout.org/docs_2006/042408O.shtml

Greenhouse Gases, Carbon Dioxide and Methane, Rise Sharply in 2007

    ScienceDaily

    Thursday 24 April 2008

    Last year alone global levels of atmospheric carbon dioxide, the
primary driver of global climate change, increased by 0.6 percent, or 19
billion tons. Additionally methane rose by 27 million tons after nearly a
decade with little or no increase. NOAA scientists released these and
other preliminary findings today as part of an annual update to the
agency's greenhouse gas index, which tracks data from 60 sites around
the world.

    The burning of coal, oil, and gas, known as fossil fuels, is the primary
source of increasing carbon dioxide emissions. Earth's oceans,
vegetation, and soils soak up half of these emissions. The rest stays in
the air for centuries or longer. Twenty percent of the 2007 fossil fuel
emissions of carbon dioxide are expected to remain in the atmosphere
for thousands of years, according to the latest scientific assessment by
the International Panel on Climate Change.

    Viewed another way, last year's carbon dioxide increase means 2.4
molecules of the gas were added to every million molecules of air,
boosting the global concentration to nearly 385 parts per million (ppm).
Pre-industrial carbon dioxide levels hovered around 280 ppm until 1850.
Human activities pushed those levels up to 380 ppm by early 2006.

    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.
When related climate affects are taken into account, methane's overall
climate impact is nearly half that of carbon dioxide.

    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.

    "We're on the lookout for the first sign of a methane release from
thawing Arctic permafrost," said Dlugokencky. "It's too soon to tell
whether last year's spike in emissions includes the start of such a
trend."

    Permafrost, or permanently frozen ground, contains vast stores of
carbon. Scientists are concerned that as the Arctic continues to warm
and permafrost thaws, carbon could seep into the atmosphere in the
form of methane, possibly fueling a cycle of carbon release and
temperature rise.

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    Adapted from materials provided by National Oceanic And
Atmospheric Adminstration.

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