[Iowa-dx] Fwd: [ Earth's temperature at highest level in 12,000 years (Chem. & Eng. News)

[hhart@blue.weeg.uiowa.edu]

CLIMATE CHANGE
Earth's Temperature At Highest Level In 12,000
Years
Climate may soon be as warm as it was 1 million
years ago

By Bette Hileman
Chemical & Engineering News, September 28, 2006
http://pubs.acs.org/cen/news/84/i40/8440climatechange.html


Earth's temperature has climbed to a level not
seen for 12,000 years, warns a new study
published online in Proceedings of the National
Academy of Sciences (DOI:
10.1073/pnas.0606291103).

The research, led by James E. Hansen, head of
NASA's Goddard Institute for Space Studies
<http://www.giss.nasa.gov>, finds that the mean
surface temperature of the planet has been
warming at a rate of 0.2 =B0C per decade for the
past 30 years. The global mean temperature is now
within 1 =B0C of the maximum for the past million
years, the study concludes.

"This evidence implies that we are getting close
to dangerous levels of human-made pollution,"
Hansen says. If additional warming is kept lower
than 1 =B0C, "the effects of global warming may be
relatively manageable. But if further warming
reaches 2 to 3 =B0C, we will likely see changes
that make Earth a different planet than the one
we know." The last time Earth was this warm was
about 3 million years ago when sea level was
about 25 meters higher than today, he explains.
If CO2 emissions are not curbed, global
temperatures are likely to rise 2 to 3 =B0C by
2100, he warns.

Hansen collaborated with David W. Lea and Martin
Medina-Elizade of the University of California,
Santa Barbara, to compare recent temperatures
with temperatures derived from sea sediments
deposited over the past million years.

The study explains that global warming is already
affecting species. Research has found that 1,700
plant and animal species are moving toward the
North or South Poles at a rate of 6 km per
decade, but over the past 30 years, climate zones
have been moving poleward at a rate of 40 km per
decade, Hansen says.