September 1, 2020
The good news, such as it is, goes like this: the suspense is over. No need to guess about whether sea level rise will be life-altering by the end of this century or not. It will, at least for the 40 percent of humankind which lives on or near a coastline. That's because all the ice on Greenland is going to melt, according to researchers at Ohio State University (yes, yes, I know - it's THE Ohio State University. Get over yourselves.) Their research appeared in the journal Nature Communications Earth and Environment in August. Total meltdown will take 10,000 years, but enough will have melted by 2100 to cause sea level rise of approximately three feet. That will cover a lot of coastal property, a loss made worse by storms and hurricanes.
How have researchers reached this conclusion? By studying almost 40 years of satellite data. Glaciers on Greenland have shrunk so much since the year 2000 that even if global warming came to a complete stop, they would continue to melt. You see, as long as the amount of snow that falls on Greenland exceeds or equals the amount of ice that melts during the summer, sea level rise is of no concern. However, according to Michalea King, lead author of the OSU Byrd Polar and Climate Research Center report, " . . . ice that's discharging into the ocean is far surpassing the snow that's accumulating on the surface of the ice sheet." The amount of ice being lost annually comes to 500 gigatons (a gigaton equals a billion tons), as opposed to 450 gigatons prior to 2000.
That's a lot of ice melt. In fact, Greenland's melting glaciers presently contribute more than a millimeter rise in sea level each year. Last year, enough ice melted or broke off that the oceans rose 2.2 millimeters in just two months! The OSU study also reveals that large glaciers across Greenland have retreated about 3 kilometers on average since 1985. Many of them now sit in ocean water, the warmth of which causes them to melt more quickly. "Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss," according to Ian Howat, a co-author on the paper. "Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass." Combined with the phenomenon of albedo, whereby light-colored surfaces (like snow) reflect the sun's warmth, and dark-colored surfaces (like ocean and land) absorb it, there is little chance of a decrease in ice melt.
Knowing what to expect may help us in preparing for what lies ahead. How much better it would be if we would work to prevent catastrophes like the collapse of Greenland's glaciers. There's only a little time left.
With thanks to Axios, Cnn.com, and phys.org.
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