Thursday,
October 9, 2008
Science
Global
Warming
Subhankar
Banerjee/Associated Press
On Feb. 2, 2007, the United
Nations scientific panel studying climate
change declared that the evidence of a warming trend is
"unequivocal," and that human activity has "very likely"
been the driving force in that change over the last 50 years. The last
report
by the group, the Intergovernmental Panel on Climate Change, in 2001,
had found
that humanity had "likely" played a role.
The addition of that single
word "very" did more than
reflect mounting scientific evidence that the release of carbon dioxide
and
other heat-trapping gases from smokestacks, tailpipes and burning
forests has
played a central role in raising the average surface temperature of the
earth
by more than 1 degree Fahrenheit since 1900. It also added new momentum
to a
debate that now seems centered less over whether humans are warming the
planet,
but instead over what to do about it. In recent months, business groups
have
banded together to make unprecedented calls for federal regulation of
greenhouse gases. The subject had a red-carpet moment when former Vice
President Al Gore's documentary, "An Inconvenient Truth," was awarded
an Oscar; and the Supreme Court made its first global warming-related
decision,
ruling 5 to 4 that the Environmental Protection Agency had not
justified its
position that it was not authorized to regulate carbon dioxide.
The greenhouse effect has been
part of the earth's workings since its
earliest days. Gases like carbon dioxide and methane allow sunlight to
reach
the earth, but prevent some of the resulting heat from radiating back
out into space.
Without the greenhouse effect, the planet would never have warmed
enough to
allow life to form. But as ever larger amounts of carbon dioxide have
been
released along with the development of industrial economies, the
atmosphere has
grown warmer at an accelerating rate: Since 1970, temperatures have
gone up at
nearly three times the average for the 20th century.
The latest report from the climate panel predicted that the global climate is likely to rise between 3.5 and 8 degrees Fahrenheit if the carbon dioxide concentration in the atmosphere reaches twice the level of 1750. By 2100, sea levels are likely to rise between 7 to 23 inches, it said, and the changes now underway will continue for centuries to come.
Related:
More
About Global Warming From The Learning Network
Highlights From
the Archives
A
Push to
Increase Icebreakers in the Arctic
By ANDREW C. REVKIN
A growing array of military
leaders, Arctic experts
and lawmakers say the
August
17, 2008WorldNews
Study
Details
How U.S. Could Cut 28% of Greenhouse Gases
By MATTHEW L. WALD
A new report says the country
is brimming with
opportunities to reduce carbon dioxide emissions, while saving money at
the
same time.
November
30, 2007BusinessNews
U.N.
Report
Describes Risks of Inaction on Climate Change
By ELISABETH ROSENTHAL
In its final and most powerful
report, an
international panel details mounting risks in specific and forceful
language,
scientists said.
November
17, 2007ScienceNews
Essay
On
the Climate
Change Beat, Doubt Gives Way to Certainty
By WILLIAM K. STEVENS
It has been pointed out many
times that we are
engaged in a titanic global experiment. The further it proceeds, the
clearer
the picture should become.
February
6, 2007ScienceNews
Science
Panel
Calls Global Warming ‘Unequivocal’
By ELISABETH
ROSENTHAL and ANDREW C. REVKIN
The report said warming and
its harmful
consequences could be substantially blunted by prompt action.
