A five-nation scientific team has published new evidence that even a slight rise in atmospheric concentrations of carbon dioxide, one of the gases that drives global warming, affects the stability of the West Antarctic Ice Sheet (WAIS). The massive WAIS covers the continent on the Pacific side of the Transantarctic Mountains. Any substantial melting of the ice sheet would cause a rise in global sea levels.
The research is based on investigations by a 56-member team
of scientists conducted on a 4,100-foot-long sedimentary rock core taken from
beneath the sea floor under Antarctica's Ross Ice Shelf during the first
project of the ANDRILL (ANtarctic geological DRILLing) research program – the
McMurdo Ice Shelf (MIS) Project.
"The sedimentary record from the ANDRILL project
provides scientists with an important analogue that can be used to help predict
how ice shelves and the massive WAIS will respond to future global warming over
the next few centuries," says Ross Powell, a professor of geology at
Northern Illinois University.
ANDRILL – which involves scientists from the United States,
New Zealand, Italy and Germany – refines previous findings about the
relationship between atmospheric carbon dioxide concentration, atmospheric and
oceanic temperatures, sea level rise and natural cycles in Earth's orbit around
the Sun, through the study of sediment and rock cores that are a geological
archive of past climate.
The cores retrieved by ANDRILL researchers have allowed them
to peer back in time to the Pliocene era, roughly 2 million to 5 million years
ago. During that era, the Antarctic was in a natural climate state that was
warmer than today, and atmospheric carbon dioxide levels were higher. Data from
the cores indicate the WAIS advanced and retreated numerous times in response
to forcing driven by these climate cycles.
The ANDRILL Science Management Office, located at the
University of Nebraska-Lincoln, supports science planning and the activities of
the international ANDRILL Science Committee (ASC). Antarctica New Zealand is
the ANDRILL project operator, and has developed the drilling system in
collaboration with Alex Pyne at Victoria University of Wellington and Webster
Drilling and Exploration.
The U.S. Antarctic Program and Raytheon Polar
Services Corporation (RPSC) supported the science team at McMurdo Station and
in the Crary Science and Engineering Laboratory, while Antarctica New
Zealand supported the drilling team at Scott Base.
Drill Cores Present New Evidence of Climate Change
April 9, 2009