Covering an area approximately three times the size of Texas, Greenland's ice sheet is the Earth's second largest body of ice and should this behemoth melt due to global warming, the world's sea levels could significantly rise, a phenomenon that could have serious impacts and particularly threaten low-lying areas such as Bangladesh and Florida. Now, two new studies reveal that the melting of the Greenland ice sheet could be faster than previously estimated.
Scientists estimated that the world's oceans would rise by as much as 20 feet should all of Greenland's ice melt. It may not happen in our lifetime but by 2100, the ice losses are predicted to result in sea level rise of 8 inches. Findings of a study published in Nature Climate Change on Dec. 15, however, suggest that this figure is underestimated because these did not take into account the effects of the so-called superglacial lakes.
Amber Leeson, from the School of Earth and Environment at the University of Leeds, and colleagues simulated the future distribution of superglacial lakes, which form on the surface of ice sheets.
The effect of these lakes on the melting of ice in Greenland was previously assumed to be small, but new study reveals that once superglacial lakes become large enough, they drain through the fractures of the ice. As a result, water reaches the base of the ice sheet causing it to slide more rapidly into the ocean and trigger further melting. The researchers said that area of Greenland covered by Superglacial lakes will double by 2060.
"Up to half of these new lakes may be large enough to drain, potentially delivering water and heat to the ice-sheet base in regions where subglacial drainage is inefficient," the researchers wrote.
In another study published in PNAS, Beata Csatho, from the University at Buffalo, and colleagues found out that there are loopholes in existing computer models that focus on four glaciers to predict how Greenland's ice sheets may change in the future.
Using satellite and airborne data to know how the ice sheet at almost 100 locations across Greenland has changed from 1993 to 2012, the researchers found that there are areas of rapid shrinkage that are not being accounted for in today's model which could mean that the ice sheet could lose ice faster that what is being suggested by existing simulations.
"The local climate and geological conditions, the local hydrology - all of these factors have an effect. The current models do not address this complexity," Csatho said.