“If you put an ice cube in a warm room, it will melt in several hours. But if you put an ice cube in a cup of warm water, it will disappear in just minutes.”
This is the problem facing the Polar ice sheets over the rest of the 21st century, according to new research which shows that warming of the ocean’s subsurface layers will speed up the melting of the ice sheets by melting underwater of Greenland and Antarctica.
The research, led by the University of Arizona, shows that such melting will only increase the speed at which the sea level increases.
“To my knowledge, this study is the first to quantify and compare future ocean warming around the Greenland and the Antarctic ice sheets using an ensemble of models,” said lead author Jianjun Yin, a UA assistant professor of geosciences, although, we reported here at Planetsave the other day about a similar study which looked at the West Antrarctic’s Pine Island Glacier Ice Shelf.
The researchers used 19 state of the art climate models and found that, in addition to being warmed by atmospheric changes, the polar ice sheets will also suffer from below as well.
Based on a med-level increase in greenhouse gases in the atmosphere, the researchers calculated that the ocean layer making up between 650 to 1,650 feet (200 to 500 meters) below the surface would warm, on average, about 1.8 F (1 C) by 2100.
Along the Greenland coast, that layer would warm twice as much, but along Antarctica would warm less, only 0.9 F (0.5 C).
“No one has noticed this discrepancy before – that the subsurface oceans surrounding Greenland and Antarctica warm very differently,” Yin said. The difference is that Greenland has to deal with the Gulf Stream carrying warm subtropical waters north, while the Antarctic Circumpolar Current blocks some of the warmth being carried south.
“This does mean that both Greenland and Antarctica are probably going melt faster than the scientific community previously thought,” said co-author Jonathan T. Overpeck, a University of Arizona professor of geosciences and co-director of the UA’s Institute of the Environment. “This paper adds to the evidence that we could have sea level rise by the end of this century of around 1 meter and a good deal more in succeeding centuries.”