Greenland hasn’t always been covered in ice and it may have melted away as recently as 400,000 years ago. That’s among findings by a team of researchers, including Utah State University geoscientist Tammy Rittenour, released March 15 in the Proceedings of the National Academy of Sciences.
Rittenour is featured in a KSL-TV news story about the multi-institution project.
How the research team found data to support their investigation reads like a mid-century spy thriller: In 1960, as the Cold War heated up, the U.S. Army launched “Project Iceworm,” a top secret effort to build a network of mobile nuclear launch sites under the Greenland Ice Sheet. Hampered by brutal blizzards and unstable ice conditions, the project, hidden in a cavernous, underground bunker cut into the ice sheet at Camp Century in northwestern Greenland, was abandoned in 1966.
A curious remnant of the doomed project – unique sediment collected at the bottom of a 1.3-kilometer-long ice core extracted from the site – languished in storage for years at New York’s University of Buffalo before transfer to Denmark’s University of Copenhagen. Largely forgotten for decades, the sub-ice samples, which captured a rare slice of dirt from beneath the ice sheet, sparked the intense, multinational study. Rittenour was among experts tapped to analyze the precious, rarer-than-Moon rocks, specimens.
“I was invited to help with the project because of my expertise with optically stimulated luminescence (OSL) dating,” says Rittenour, professor in USU’s Department of Geosciences and director of the USU Luminescence Laboratory, one of a few such research facilities in the United States.
Stored in 28 glass “cookie jars,” the muddy sediment collected from beneath Camp Century provides an extraordinary glimpse into the past, Rittenour says.
And that glimpse is sobering. The team’s findings challenge long-held assumptions the Greenland Ice Sheet has covered Camp Century’s site, without interruption, for more than two million years.
“The Greenland Ice Sheet is more fragile and sensitive to climate change than we thought,” says Rittenour, a Geological Society of America Fellow. “The ice sheet is melting at an alarming rate, which doesn’t bode well for the world’s coastal communities.”
Using ice-core data and instrumental data recording carbon dioxide (CO2) concentrations over time, Rittenour and colleagues note the alarming increase in post-industrial CO2 seen in the last 50 years is well outside natural atmospheric CO2 levels.
“Implications of this finding are important, because if the Greenland Ice Sheet can be lost under natural conditions, then current, unprecedented warming, linked to increased CO2 and other greenhouse gases, is a dangerous recipe for uncontrolled melting of the ice sheet and resultant sea level rise,” Rittenour says. “Contributions from the Greenland Ice Sheet alone will raise sea level by more than 24 feet.”
Most of the world’s population, some 40 percent, live within about 60 miles of the ocean.
“Think about the world’s major coastal cities in all hemispheres: New York City, Shanghai, Mumbai, not to mention whole island nations that could be devastated by flooding,” Rittenour says. “We’re talking about initial sea-level rise within decades.”
In addition to USU, institutions involved in the research project include University of Vermont, Columbia University, Denmark’s University of Copenhagen, Canada’s University of Manitoba, University of Buffalo, University of Washington, Belgium’s Université Libre de Bruxelles, France’s Université de Lorraine, Purdue University, University of California, Irvine; as well as NASA and Lawrence Livermore National Laboratory.
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Associate Professor and Director
Department of Geosciences and USU Ecology Center; USU Luminescence Laboratory