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.