Hot Year Blamed on Rising Greenhouse Gases
Pastor Dale Morgan
Aug 28, 2:38 PM EDT
*Hot Year Blamed on Rising Greenhouse Gases*
by RANDOLPH E. SCHMID
AP Science Writer
WASHINGTON (AP) -- "We have met the enemy, and he is us," the
comic-strip character Pogo said decades ago. A new analysis of last
year's near-record temperatures in the United States suggests he was right.
Warming caused by human activity was the biggest factor in the high
temperatures recorded in 2006, according to a report by researchers at
the National Oceanic and Atmospheric Administration.
The analysis, released Tuesday, is being published in the September
issue of Geophysical Research Letters, published by the American
Geophysical Union.
In January, NOAA's National Climatic Data Center reported that 2006 was
the warmest year on record over the 48 contiguous states with an average
temperature 2.1 degrees Fahrenheit warmer than normal and 0.07 degree
warmer than 1998, the previous warmest year on record.
In May, however, NOAA revised the 2006 ranking to the second warmest
year after updated statistics showed the year was actually .08 F cooler
than 1998.
At the time the agency said it was not clear how much of the warming was
a result of greenhouse-gas induced climate change and how much resulted
from the El Nino warming of the tropical Pacific Ocean that was under way.
"We wanted to find out whether it was pure coincidence that the two
warmest years on record both coincided with El Nino events," Martin
Hoerling of NOAA's Earth System Research Laboratory in Boulder, Colo.,
said in a statement.
His study looked at the effects of El Nino in the past as well as the
effects of the release of gases such as carbon dioxide into the
atmosphere by human industrial activities.
The analysis of past El Nino events in the 20th century found that the
result was a slightly colder than normal annual average temperature over
the 48 contiguous states.
To double check that, the researchers conducted two sets of 50-year
computer simulations of U.S. climate, with and without the influence of
El Nino. They again found a slight cooling across the nation when El
Nino was present.
Then they looked at the effect of the increased greenhouse gases - which
are given that name because they can help trap heat from the sun
somewhat like a greenhouse traps heat.
They ran 42 different tests using complex computer models to simulate
changes in the atmosphere under various conditions and concluded that
the "2006 warmth was primarily due to human influences."
While Hoerling's study focused on the United States, NOAA also tracks
world climate. Worldwide, 2005 was the warmest year on record, topping
1998, according to the agency.
The research was supported by NOAA's office of Global Programs.
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In the Net:
NOAA: http://www.noaa.gov
AGU: http://www.agu.org