A pair of new studies into Greenland’s ice sheet has challenged existing models that may overestimate just how much meltwater actually runs out to sea.
What’s happening?
The Brown Daily Herald, a student newspaper at Brown University, reported that the two studies, both published this September in the journal Nature Communications, examined overlooked aspects of where meltwater ultimately ends up.
Researchers conducted fieldwork in southwestern Greenland to measure ice loss and the flow rate of a river into which the meltwater drained. The research found a discrepancy between how much ice was being lost and how much was actually flowing out to sea.
By day, warmer temperatures cause the ice to melt, but much colder nocturnal temperatures cause a significant portion of the melted ice to be “retained and refrozen within porous bare ice,” according to study co-author Matthew Cooper.
Some of the meltwater forms ponds on the surface, which don’t flow out to sea but do accelerate ice loss by making the ice sheet darker and less reflective.
Cooper, a water and climate scientist at the University of California, Los Angeles, told the Herald that, if applied to the whole southwestern region, the team’s findings suggest that “retained and refrozen” meltwater could equal “roughly 11 to 17 gigatons per year, equivalent to about 9 to 15 percent of modeled annual runoff from that sector.”
Why is an accurate picture of Greenland’s ice sheet so important?
The Arctic is the fastest-warming region in the world. Driven by planet-heating pollution — a result of burning dirty energy sources — ice loss there is altering weather patterns and contributing to rising sea levels.
While a determination that the rate of outflow might not be quite as high as previously feared could be viewed as slightly reassuring, the melting of ice sheets and glaciers is still a significant global concern. Its direct consequences are already being felt in many low-lying island nations.
For these reasons, it’s critical that researchers work to fully and precisely understand rates of ice loss. Their findings could help inform policies and practices to better protect not only the Arctic but also vulnerable populations worldwide.
What’s being done to protect the Arctic?
It’s imperative for affected communities and effective decision-makers to have the most accurate models possible. Up-to-date and high-quality information could lead to decisive global agreements to curb harmful pollution. We need only look to the recovery of the ozone layer for evidence that international cooperation can achieve meaningful results.
Ultimately, mitigating the loss of ice sheets and glaciers will require a mass transition away from dirty fuels, such as oil and gas, and toward clean energy sources, such as solar and wind. In the meantime, researchers like Cooper, along with co-authors Jonathan Ryan, Brown professor Laurence Smith, and others, plan to continue the rigorous fieldwork essential to learning more about the melting Arctic.
“We camp right in the melt zone, pitch our tents, there’s water flowing all over the place,” Smith told the Brown Daily Herald. “We have to tether into harnesses and ropes [and] mark off a safe perimeter of the camp.” But, as Ryan told the paper, the work is “very rewarding.”
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