A team of climate scientists and geologists including Robert DeConto at the University of Massachusetts Amherst recently received a five-year, $7 million grant from the National Science Foundation to drill through the Greenland Ice Sheet and into the bedrock below, where they will be able to evaluate how long it has been since the last ice sheet retreated from the continent.
Greenland’s ice sheet holds enough water to raise sea levels nearly 24 feet, and scientists have confirmed that this amount has melted at least once in the last million years, DeConto says. “An overarching question we’re trying to answer is just how sensitive the Greenland Ice Sheet is to a warmer climate. Loss of the ice sheet, even a small amount, would be catastrophic for many people and coastlines,” he adds.
In addition to UMass Amherst, investigators at Columbia, Penn State and the University at Buffalo will receive $3 million in research funds and $4 million for field operations from the National Science Foundation for the project, dubbed GreenDrill. Drilling at four sites will go through hundreds of meters of ice before collecting bedrock.
Columbia geochemist Joerg Schaefer notes that bedrock contains isotopes produced by cosmic rays hitting certain atoms’ nuclei, where they accumulate in rock after exposure to the sun. Analyzing the isotopes will show when and how the ice receded. Schaefer says the rocks there are “comparable to the moon rocks in their rareness and preciousness.”
Among other things, the researchers will use the new data to test the hypothesis that northern Greenland is more sensitive to warming than the southern part. DeConto says, “This project has the potential to substantially improve our understanding of how the ice sheet behaves and responds to a warmer world – with great benefits to society. For a climate scientist, that’s about as exciting as it gets!”
The professor of geosciences and co-director of UMass Amherst’s School of Earth & Sustainability will lead climate- and ice-sheet modeling activities that are central to the project. Modeling will help to explain the geological observations uncovered by the drilling team, he explains. Testing computer models used to make future projections of sea-level rise against geological observations is one of the best ways to gain confidence in our understanding of what the future might hold, he adds.
DeConto and colleagues will also explore how far the ice sheet can be pushed before ice loss become unstoppable and irreversible, and what part of the ice sheet is likely to respond first to a warming climate.
The project is focused on the northern part of the ice adjacent to the Arctic Ocean, which is now warming very quickly, he notes. “There are likely important linkages between the Arctic Ocean – its temperature and loss of sea ice – and the health of the ice sheet.”
The climate- and ice-modeling expert also notes, “It’s absolutely critical that we know how much ice Greenland lost in the past, and this is still very uncertain. GreenDrill will help to answer this question.” Knowing the past informs scientists about the future, he adds, such as the ice sheet’s sensitivity to warming and “how much sea level rise we should be planning for.”
GreenDrill includes an education and outreach component aimed at encouraging diversity and inclusion in the geosciences. Undergraduate students and early-career scientists will be recruited to participate in the research, the researchers note.
UMass Amherst Climate Modeler and Team Will Drill Under Greenland’s Ice Sheet to Date its Last Retreat