There's a massive, unstable glacier in Antarctica that could cause a dramatic rise in sea level, and Penn State researchers are on the forefront of trying to understand what it means for the future.
Penn State, along with other institutions around the country and abroad, is part of a $25 million, eight-project initiative to study the remote Thwaites Glacier in West Antarctica, which is almost 1,000 miles from the nearest permanently occupied research station.
The research collaboration, funded by the U.S. National Science Foundation and its U.K. equivalent, the Natural Environmental Research Council, will involve about 100 scientists from seven countries and span five years. It's the largest joint project between the U.S. and U.K. undertaken in Antarctica in more than 70 years.
"Satellites show the Thwaites region is changing rapidly, but to answer the key questions of how much, and how quickly sea-level will change in the future requires scientists on the ground with sophisticated equipment collecting the data we need to measure rates of ice-volume, or ice-mass change," William Easterling, assistant director for NSF's Geosciences Directorate and former dean of Penn State's College of Earth and Mineral Sciences, said in a press release.
Penn Staters are involved in two of the eight projects, GHOST and MELT.
Sridhar Anandakrishnan, a Penn State geosciences professor, is the principal investigator for GHOST — Geophysical Habitat of Subglacial Thwaites. He's also a co-principal investigator for MELT.
The purpose of GHOST is to gain a better understanding of the base of Thwaites Glacier — where the ice meets rock. He said the glacier is sliding over that surface, and so to make better computer models and predict the future of what that glacier might look like, they need more information about that surface.
Anandakrishnan has been to Thwaites Glacier three times, and will go again as part of this research collaboration. He said field work for GHOST is set to take place from about November to January in 2019 and again in 2020, as that's summertime in Antarctica.
The MELT project will study the ice shelf — a large, connected mass of floating ice out in front of Thwaites Glacier, he said. The project will involved drilling a "bunch" of holes through the ice and putting oceanographic instruments below, because there's ocean water that "infiltrates" underneath the ice shelf. Those instruments will measure things like temperature and circulation.
"Ultimately, the goal of both these projects, and the other Thwaites projects, is to assess how Thwaites Glacier might respond to ongoing human caused climate change in the next 50-100 years," Anandakrishnan said.
Thwaites, which would easily cover most of Pennsylvania, already accounts for about 4 percent of global sea-level rise.
Anandakrishnan said it's hundreds of kilometers long and a couple hundred kilometers wide, and 2 kilometers thick, on average. So there's a "huge" amount of ice physically in it.
If "a glacier dumps more ice into the ocean each year than it receives by snowfall, then that difference goes to raising sea level," he said.
He said Thwaites is "particularly, possibly vulnerable" to this process because of its unusual geometry.
The glacier sits facing the ocean, and the rock underneath it gets deeper as it gets farther away from the ocean, he said. And that huge "bowl" is filled up with the glacier. Because Thwaites sits in that "deep bowl," it's "unstable and liable to very rapid mass loss."
Models suggest that if Thwaites were to start getting thinner and thinner, then it would be a "runaway process," Anandakrishnan said.
"If it's as dangerous as some people think it is, then it's really, really dangerous," he said.
"We don't know enough about Thwaites to know how much warming would be needed to trigger this retreat, but many studies agree that humans could cause that much warming if we don't change our behavior, and perhaps well within this century," Richard Alley, Evan Pugh Professor of Geosciences at Penn State and GHOST researcher, said in an email.
Alley and Anandakrishnan said that if society doesn't do anything to reduce carbon emissions, then in 100 years global sea levels could rise a few feet.
"Thwaites Glacier is an added danger," Anandakrishnan said, saying its collapse could add two to three more feet to sea level rise over the next century.
Alley, though, said Thwaites, as a major outlet of the West Antarctic Ice Sheet and owing to its unique geometry, could raise global sea level by about 11 feet.
"Sea-level rise is important for people, because a lot of homes, and roads, and lives, can be endangered by flooding," Alley said. "... This rise is occurring because of warming, which is primarily driven by release of CO2 from fossil fuel burning by humans. ... The rate of sea level rise is accelerating a little, and more rise is almost unavoidable. But, human decisions will be very important in determining how much more rise we will experience."
But Anandakrishnan said making changes like switching to renewable energy and higher efficiency cars can have an impact.
"All these things are possible without that much effort, without too much disruption of our way of life," he said, adding that it just takes effort and commitment from a lot of people to make it happen.