U.S. Department of the Interior
U.S. Geological Survey
For release: December 16, 2008
Contact:
John McGeehin, 703-648-5349, mcgeehin@xxxxxxxx
Jessica Robertson, c 202-821-2698, w
703-648-6624, jrobertson@xxxxxxxx
Abrupt Climate Change: Will It
Happen this Century?
The United States faces the potential
for abrupt climate change in the 21st century that could pose clear risks
to society in terms of our ability to adapt.
“Abrupt” changes can occur over
decades or less, persist for decades more, and cause substantial disruptions
to human and natural systems.
A new report, based on an assessment
of published science literature, makes the following conclusions about
the potential for abrupt climate changes from global warming during this
century.
Climate model simulations and observations
suggest that rapid and sustained September arctic sea ice loss is likely
in the 21st century.
The southwestern United States
may be beginning an abrupt period of increased drought.
It is very likely that the northward
flow of warm water in the upper layers of the Atlantic Ocean, which has
an important impact on the global climate system, will decrease by approximately
25–30 percent. However, it is very unlikely that this circulation will
collapse or that the weakening will occur abruptly during the 21st
century and beyond.
An abrupt change in sea level is
possible, but predictions are highly uncertain due to shortcomings in existing
climate models.
There is unlikely to be an abrupt
release of methane, a powerful greenhouse gas, to the atmosphere from deposits
in the earth. However, it is very likely that the pace of methane emissions
will increase.
The U.S. Geological Survey led
the new assessment, which was authored by a team of climate scientists
from the federal government and academia. The report was commissioned by
the U.S. Climate Change Science Program with contributions from the National
Oceanic and Atmospheric Administration and the National Science Foundation.
“This report was truly a collaborative effort between
world renowned scientists who
provided objective, unbiased information that is necessary to develop effective
adaptation and mitigation strategies that protect our livelihood,”
said USGS Director Mark Myers. “It summarizes the scientific community’s
growing understanding regarding the potential for abrupt climate changes
and identifies areas for additional research to further improve climate
models.”
Further research is needed to improve
our understanding of the potential for abrupt changes in climate. For example,
the report’s scientists found that processes such as interaction of warm
ocean waters with the periphery of ice sheets and ice shelves have a greater
impact than previously known on the destabilization of ice sheets that
might accelerate sea-level rise.
To view the full report, titled
Synthesis and Assessment Product 3.4: Abrupt Climate Change, and
a summary brochure on abrupt climate change, visit http://www.climatescience.gov/default.php.
USGS provides science for a changing
world. For more information, visit www.usgs.gov.
