Climate scientists have been growing increasingly concerned with the large rivers of ice making their way into the ocean from Greenland and Antarctica, pointing to their potential to accelerate as the planet continues to warm and increase the chances of a collapse of the Earth's ice sheets. Now, a new study by researchers from the University at Buffalo reveals a new manner in which ice sheets can disappear, marking a huge advancement in our understanding of ice sheet behavior and climate change.
The study examined the Laurentide Ice Sheet, which covered the majority of North America until approximately 10,000 years ago. The researchers historically reconstructed the behavior of the ice streams as the ice sheet was destroyed and found that the ice loss in the frozen rivers did not show a rapid increase as the ice sheet disintegrated.
"Their evidence shows that ice streams turned on and off, and shifted from place to place, during the disappearance of the Laurentide Ice Sheet - the Antarctic-sized ice sheet that occupied Canada and the northern United States at that time," Jason Briner, who was not involved in the research, said in a press release. "Perhaps most notably, Stokes and colleagues find that ice-stream activity decreased as the planet warmed: the number of ice streams fell, the amount of ice expunged by them decreased and ice streams occupied a progressively smaller percentage of the ice-sheet edge."
However, Briner makes it clear that this does not mean that today's ice sheets will exhibit the same behavior as the Laurentide did due to their numerous differences. Nevertheless, the findings represent a "leap forward in our view of ice-stream activity on timescales longer than a few decades," according to Briner.
The results shed light on the behavior of ice streams over long periods of time, and as the Greenland and Antarctic ice sheets continue to dwindle, their behavior may soon resemble that of the Laurentide.
Briner claims that this area of research is valuable because many scientists still do not know how frozen rivers can shed ice and drive the sea level as the planet continues to warm.
"Greenland has three major ice streams - Jakobshavn, Kangerlussuaq and Helheim - and in the early 2000s, they all madly accelerated at the same time. So we had this doomsday scenario for a while, because if they continued to accelerate, their discharges into the ocean would be huge," he said.
"Then, several years later, they slowed down again. There is still a lot we don't know about how these ice streams behave, and understanding their behavior is crucial for accurate modeling of future ice sheet decline," Briner concluded.
The findings were published in the Feb. 17 issue of Nature.
