Change >> Global Warming
Global Temperature Highest in Millenia
WASHINGTON - September 26, 2006 - The planet's temperature
has climbed to levels not seen in thousands of years,
warming that has begun to affect plants and animals,
researchers report in Tuesday's issue of Proceedings
of the National Academy of Sciences.
The Earth has been warming at a rate of 0.36 degree
Fahrenheit per decade for the last 30 years, according
to the research team led by James Hansen of NASA's
Goddard Institute for Space Studies in New York.
That brings the overall temperature to the warmest
in the current interglacial period, which began about
12,000 years ago.
The researchers noted that a report in the journal
Nature found that 1,700 plant, animal and insect species
moved poleward at an average rate of about 4 miles
per decade in the last half of the 20th century.
The warming has been stronger in the far north, where
melting ice and snow expose darker land and rocks
beneath allowing more warmth from the sun to be absorbed,
and more over land than water.
Water changes temperature more slowly than land because
of its great capacity to hold heat, but the researchers
noted that the warming has been marked in the Indian
and western Pacific Oceans. Those oceans have a major
effect on climate and warming that could lead to more
El Nino episodes affecting the weather.
"This evidence implies that we are getting close to
dangerous levels of human-made pollution," Hansen
said in a statement.
Few scientists doubt that the planet has warmed, though
some question the causes of the change.
Hansen, who first warned of the danger of climate
change decades ago, said that human-made greenhouse
gases have become the dominant climate change factor.
The study said the recent warming has brought global
temperature to a level within about one degree Celsius
_ 1.8 degree Fahrenheit _ of the maximum temperature
of the past million years.
"If further global warming reaches 2 or 3 degrees
Celsius, we will likely see changes that make Earth
a different planet than the one we know. The last
time it was that warm was in the middle Pliocene,
about 3 million years ago, when sea level was estimated
to have been about 25 meters (80 feet) higher than
today," Hansen said.
Â© 2006 Associated Press