Authors are Brice Noël1,*, Willem Jan van de Berg1, Stef Lhermitte2 and Michiel R. van den Broeke1

1Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands.

2Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, Netherlands.

Science Advances 04 Sep 2019:
Vol. 5, no. 9, eaaw0123
DOI: 10.1126/sciadv.aaw0123

Abstract — Since the early 1990s, the Greenland ice sheet (GrIS) has been losing mass at an accelerating rate, primarily due to enhanced meltwater runoff following atmospheric warming. Here, we show that a pronounced latitudinal contrast exists in the GrIS response to recent warming.

The ablation area in north Greenland expanded by 46%, almost twice as much as in the south (+25%), significantly increasing the relative contribution of the north to total GrIS mass loss. This latitudinal contrast originates from a different response to the recent change in large-scale Arctic summertime atmospheric circulation, promoting southwesterly advection of warm air toward the GrIS.

In the southwest, persistent high atmospheric pressure reduced cloudiness, increasing runoff through enhanced absorption of solar radiation; in contrast, increased early-summer cloudiness in north Greenland enhanced atmospheric warming through decreased longwave heat loss. This triggered a rapid snowline retreat, causing early bare ice exposure, amplifying northern runoff.

https://advances.sciencemag.org/content/5/9/eaaw0123.full

From Adele Peters, Co.Exist, November 10, 2016

In September 1984, there were more than a million square miles of thick, older sea ice in the Arctic—an area roughly the size of Alaska, Texas, and California combined. By September 2016, multi-year ice had shrunk to only around 68,000 square miles (a little smaller than Missouri).

All Arctic ice has been steadily disappearing, but the loss of older ice is especially problematic because—as one NASA researcher puts it—it’s an “insurance policy” for the rest of the pack. The less older sea ice remains, the more likely it is that the Arctic could be completely ice-free in the summer.

This older, thicker ice is like the bulwark of sea ice: a warm summer will melt all the young, thin ice away but it can’t completely get rid of the older ice. That bulwark is not as good as it used to be. The older ice is becoming weaker because there is less of it, and the remaining ice is more broken up and thinner.

A NASA animation shows the shrinking ice. The oldest ice is white, while darker colors depict newer ice.

Unlike the massive sheets of freshwater ice in Greenland and Antarctica, melting sea ice won’t make sea levels higher on its own (the ice displaces the same amount of water as it would if it were liquid). But as it melts, and can’t reflect as much sunlight, the more heat the planet absorbs. Rising Arctic temperatures make even more ice melt (including the ice in Greenland), and make the permafrost melt, which releases even more greenhouse gases.

Some researchers predict that the Arctic could be essentially ice-free by the summer of 2017 or 2018.

ACCESS: https://www.fastcoexist.com/3065481/watch-how-quickly-arctic-sea-ice-disappearing

See also: http://www.FrackCheckWV.net