Polar Scientist Looks Back To Predict Future Ice Melt

Earth and Environmental Studies Professor Sandra Passchier will use data from millions of years ago to predict Antarctic ice sheet response to global warming.

The Antarctic ice sheet (AIS) covers 5.4 million square miles, or 98 percent, of a continent roughly the size of North America — and Passchier’s research is devoted to exposing the secrets of AIS dynamics. A recent $323,113 National Science Foundation award supports her three-year project that will help scientists forecast global sea level rise.

A pioneering polar scientist in the field of internationally coordinated Antarctic research, Passchier is currently focusing on West Antarctica, where ice melt has tripled in the past 15 years. “Understanding how the West Antarctica ice sheet responds to global warming is crucial in providing accurate sea level predictions,” says Passchier, who hopes to make her sixth trip to Antarctica in early 2019.

By going back in time to show the effect of greenhouse forcing on ice sheet development, Passchier says her findings will show “how ice sheets and sea level behaved under conditions of higher levels of greenhouse gases in the atmosphere than we have today — levels that are similar to those we will reach in a few decades if these emissions aren’t curtailed or mitigated.”

As a team member on five previous international science drilling programs, she helped extract sedimentary core samples from hundreds of meters beneath the Antarctica sea floor. Now, Passchier — and undergraduate and graduate students — will analyze these and other archived samples to reconstruct the timing and spatial distribution of Antarctic ice growth during the greenhouse-to-icehouse climate change that affected the entire planet 37 to 33 million years ago. The new paleo-climate data will help project the AIS response to continued global warming.

“Current greenhouse gas levels are higher than at any time in human history,” she explains. “To understand this climate state, we need to assess earth processes from millions of years ago and study the history of the AIS and climate system in the geological archives buried in layers of mud under Antarctica’s sea floor.”