By RANDOLPH E. SCHMID, Associated Press Writer
The effect of greenhouse gases on the Earth's atmosphere has increased
20 percent since 1990, a new government index says.
The Annual Greenhouse Gas Index was released Tuesday by the Climate
Monitoring and Diagnostics Laboratory in Boulder, Colo.
Greenhouse gases such as carbon dioxide accumulate in the atmosphere
as a result of industrial and other processes. They can help trap
solar heat, somewhat like a greenhouse, resulting in a gradual warming
of the Earth's atmosphere.
The Earth's average temperature increased about 1 degree Fahrenheit
during the 20th century. The Intergovernmental Panel on Climate Change
warns that continuing increases could have serious effects on crops,
glaciers, the spread of disease, rising sea levels and other changes.
In its new analysis the laboratory, a branch of the National Oceanic
and Atmospheric Administration, compares the amounts of carbon
dioxide, methane, nitrous oxide and chlorofluorocarbons in the
air. Those gases have been sampled for many years.
The index was set to a reading of 1 as of 1990 and the lab said it is
currently 1.20, indicating an increase of 20 percent.
"The AGGI will serve as a gauge of success or failure of future
efforts to curb carbon dioxide and other greenhouse gas increases in
the atmosphere both by natural and human-engineered processes," said
David Hofmann, CMDL director.
The index is expected to be updated each April.
"This index provides us with a valuable benchmark for tracking the
composition of the atmosphere as we seek to better understand the
dynamics of Earth's climate," said NOAA Administrator Conrad
C. Lautenbacher, Jr.
In the current reading, for every million air molecules there are
about 375 carbon dioxide molecules, two are methane and less than one
is a nitrous oxide molecule. The CFC's make up less than one molecule
in a billion in the atmosphere but play a role in regulating Earth's
climate and are a key factor in the depletion of the protective ozone
layer, NOAA researchers say.
The gases produce an effect known as radiative forcing. It is a shift
in the balance between solar radiation coming into the atmosphere and
Earth's radiation going out. Radiative forcing, as measured by the
index, is calculated from the atmospheric concentration of each
contributing gas and the per-molecule climate forcing of each gas.
The lab said most of the increase measured since 1990 is due to carbon
dioxide, which now accounts for about 62 percent of the radiative
forcing by all long-lived greenhouse gases.
NOAA said the 1990 baseline was chosen because greenhouse gas
emissions targeted by the international Kyoto Protocol also are
indexed to 1990. Although many/most countries have agreed to be
bound by the standards outlined in the international Kyoto
Protocol, United States president George Bush has repudiated it,
and refused to participate.
On the Net:
NOAA Climate Monitoring and Diagnostics Lab: http://www.cmdl.noaa.gov
Copyright 2005 The Associated Press.
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