Two of Greenland’s largest three glaciers have lost enough ice that they could have filled Lake Erie with the accumulated melted ice water.
According to data compiled at Ohio State University, three glaciers — Helheim, Kangerdlugssuaq and Jakobshavn Isbrae — are responsible for as much as one-fifth of the ice flowing out from Greenland into the ocean.
“Jakobshavn alone drains somewhere between 15 and 20 percent of all the ice flowing outward from inland to the sea,” explained Ian Howat, an assistant professor of earth sciences at Ohio State University.
“Kangerdlugssuaq would have to stop flowing and accumulate snowfall for seven years to regain the ice it has lost,” said Howat.
Howat is one of many scientists who are using Greenland as a laboratory for understanding how climate change is affecting the massive ice fields of Greenland and Antarctica. Currently, researchers like Howat are concentrating on the “mass balance” of glaciers, the rate at which new ice is formed compared to how much ice flows out to sea.
In his study, which appears in the current issue of the journal Geophysical Research Letters, Howat shows that in the last decade, Jakobshavn Isbrae has lost enough ice to equal 11 years’ worth of normal snow accumulation, approximately 300 gigatons (300 billion tons) of ice.
Unexpectedly, however, the third of the three largest Greenland glaciers, Helheim, has actually gained mass over the same period that its cousins have lost ice, gaining approximately one-fifteenth of what Jakobshavn had lost.
The real value of Howat’s research, however, is in the confirmation that the new techniques Howat and his colleagues have developed are providing more accurate data from which to work with.
“These glaciers change pretty quickly. They speed up and then slow down. There’s a pulsing in the flow of ice,” Howat said. “There’s variability, a seasonal cycle and lots of different changes in the rate that ice is flowing through these glaciers.”
Howat noted that past estimates have only been small glimpses of what was really going on in terms of glacial mass loss. “We really need to sample them very frequently or else we won’t really know how much change has occurred. This new research pumps up the resolution and gives us a kind of high-definition picture of ice loss.”