APRIL 9, 2009 ISSUE
ASU Geologist Documenting Climate Change on West Antarctic Ice Sheet
Ellen Cowan, a geology professor at ASU, was part of a multi-national scientific team that is studying climate change at the West Antarctic Ice Sheet. She spent three months at McMurdo Station in Antarctica analyzing sedimentary rock deposits drilled from more than a mile below the ocean floor under the Ross Ice Shelf. Photo courtesy of Ellen Cowan
ASU’s Ellen Cowan is part of a five-nation scientific team that has published new evidence that even a slight rise in atmospheric concentrations of carbon dioxide, a gas that drives global warming, affects the stability of the West Antarctic Ice Sheet (WAIS).
The massive WAIS is about the size of Texas and covers the continent west of the Trans-Antarctic Mountains. Any substantial melting of the ice sheet would cause a rise in global sea levels.
The research, which was published in a recent issue of the journal Nature, 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.
Cowan, a professor in ASU’s Department of Geology, spent three months in Antarctica during the 2006-07 academic year. She was one of four scientists on the project who helped describe the sedimentary rock in detail, logged the information graphically and posted it on the Internet for others to use in their research.
“My work focuses on sediment deposited by glaciers,” Cowan said. “The details in the sediment tells us what the glacier was like over time—if the ice was very cold, like it is in Antarctica today, or if it had different characteristics, like ice found in parts of Alaska or Greenland. Those fine-scale environmental clues help us understand how Antarctica has changed over the past,” Cowan said.
Ice disappeared from Antarctica millions of years ago, something scientists think could occur again in the next thousand years.
“When the climate was warmer and CO2 was higher three to five million years ago, we actually lost the ice in West Antarctica. There was not an ice shelf and there weren’t any glaciers there,” Cowan said. “That is really a key finding at this point, because it has implications for sea level change. That is something that is probably the most critical change that we will see in the world as a result of global warming, because the majority of the people in the world, particularly those in developing countries, live near the coastline.”
While no one knows when a significant melting of the ice shelf might begin, Cowan hopes governments will use the information being gleaned from the ANDRILL project and heed calls to reduce their country’s CO2 emissions.
“I hope that this type of research is another bit of evidence that [climate] change is going to be dramatic if we don’t do something about it,” she said. “We think of Antarctica as a big freezer where nothing much happens, but recent research has shown that the atmosphere over Antarctica has increased in temperature.”
“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,” said Ross Powell, a professor of geology at Northern Illinois University who was a leader of the ANDRILL team.
“The sedimentary record indicates that under global warming conditions that were similar to those projected to occur over the next century, protective ice shelves could shrink or even disappear and the WAIS would become vulnerable to melting,” Powell said. “If the current warm period persists, the ice sheet could diminish substantially or even disappear over time. This would result in a potentially significant rise in sea levels.”
“I hope we can stem the tide by reducing greenhouse gas emissions,” Cowan said. “We have time.”
The National Science Foundation, which manages the U.S. Antarctic Program, provided about $20 million in support of the ANDRILL program. The other ANDRILL national partners contributed an additional $10 million in science and logistics support.
The ANDRILL Science Management Office, located at the University of Nebraska-Lincoln, supports science planning and the activities of the international ANDRILL Science Committee. 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 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. ANDRILL scientific studies are jointly supported by the U.S. National Science Foundation, New Zealand Foundation for Research, the Italian Antarctic Research Program, the German Science Foundation and the Alfred Wegener Institute.
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