Will more snow over Antarctica offset rising seas? Don’t count on it
http://www.washington.edu/news/2016/05/19/will-more-snow-over-antarctica-offset-rising-seas-dont-count-on-it/[font size=5]Will more snow over Antarctica offset rising seas? Don’t count on it[/font]
Hannah Hickey
News and Information
[font size=3]Many factors related to warming will conspire to raise the planet’s oceans over coming decades — thermal expansion of the world’s oceans, melting of snow and ice worldwide, and the collapse of massive ice sheets.
But there are a few potential brakes. One was supposed to be heavier snowfall over the vast continent of Antarctica. Warmer air will hold more moisture and thus generate more snow to fall inland and slightly rebuild the glacier, according to climate model projections.
Not so fast, says a University of Washington study published in Geophysical Research Letters, a journal of the American Geophysical Union. The authors looked at evidence from the West Antarctic Ice Sheet Divide ice core to get a first clear look at how the continent’s snowfall has varied over 31,000 years.
“It’s allowed us to look at the snow accumulation back in time in much more detail than we’ve been able to do with any other deep ice core in Antarctica,” said lead author T.J. Fudge, a UW postdoctoral researcher in Earth and space sciences. “We show that warmer temperatures and snowfall sometimes go together, but often they don’t.”
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The reason for that is the East Antarctic Ice Sheet (EAIS) is entirely within the Antarctic Circle AND is on the highest Continent on earth (Yes, South America and Asia both have taller mountains, but both are offset by extensive low lands, Brazil, Venezuela to Argentina for South America, Siberia, Southeast Asia and India for Asia).
The location of East Antarctica and it being the highest continent means its Ice Sheets are the least affected by increases in World Wide Sea Temperatures and levels. With increase temperatures, you will have more moisture being carried to East Antarctica and thus increase snow fall and increase ice (higher temperatures permit air to carry more moisture). Now, sometimes after the collapse of both the West Antarctic Ice Sheet (WAIS) and the Greenland Ice Sheet. world wide temperatures will start to melt the ice in the East Antarctic Ice Sheet (EAIS), but NOT till then.
Now, the article that started this thread just pointed out that the increase in ice in the East Antarctic Ice Sheet (EAIS) will NOT offset the lost of ice elsewhere in the world, that is also part of most climate predictions. No one who has studied the issue ever said the increase Ice in the East Antarctic Ice Sheet (EAIS) would more then offset the lost of ice elsewhere, but it appears someone somewhere decided that the increase in the ice in the East Antarctic Ice Sheet (EAIS) would do just that. This article just punches holes into that argument.
http://www.antarcticglaciers.org/antarctica/east-antarctic-ice-sheet/
The last time CO2 was this high, the East Antarctic Ice Sheet remained stable:
http://phys.org/news/2015-12-east-antarctic-ice-sheet-frozen.html
Through sable, the East Antarctic Ice Sheet MAY have contributed to world wide sea level increase in the last inter glacial period:
http://www.sciencedirect.com/science/article/pii/S0277379113002898
NASA report that the East Antarctic Ice Sheet (EAIS) has expanded in recent years:
http://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses/
Gains in East Antarctic Ice Sheet (EAIS) is less then losses elsewhere EASI Gain 200 billion tons of ice each year, while the WAIS Loss 65 billion tons of ice each year, net gain for Antarctica of 135 billion tons of Ice each year, but sea levels are RISING so the excess of water is coming from elsewhere, the Greenland Ice Sheet or from the massive retreat of Glaciers in the rest of the world:
http://phys.org/news/2015-10-mass-gains-antarctic-ice-sheet.html
Thus most scientist report the East Antarctic Ice Sheet will be stable or even expand for the near future, that is NOT true of the West Antarctic Ice Sheet.
Now 1/5th of the East Antarctic Ice Sheet is also below sea level, but presently blocked from the sea by other glaciers and the West Antarctic Ice Sheet:
http://www.nytimes.com/2016/03/31/science/global-warming-antarctica-ice-sheet-sea-level-rise.html
Here is a map of Antarctica IF all of the ice melted:
http://www.nytimes.com/2016/03/31/science/global-warming-antarctica-ice-sheet-sea-level-rise.html
Notice how little of the West Antarctica is above sea level, but 1/5 of East Antarctica is also below sea level. 20% of 60 % is 12%. About 10% of world wide fresh water is in the Greenland Ice Sheet, about 10% is in the West Antarctic Ice Sheet, both if they melt, would raise world wide sea levels about 20 feet. That is also true of the parts of the East Antarctic Ice Sheet below sea level. Greenland Ice Sheet is considered Stable for it is above Sea Level (thus it will melt into the ocean NOT collapse into the Ocean). The West Antarctic Ice Sheet AND the part of the East Antarctic Ice Sheet that is below sea levels, can collapse over night, switching from Ice Sheets (that displace very little sea water in the ocean) to Ice shelves that displace 100% of the water they will be when they melt. Thus if either collapses. you have a huge amount of ice FLOATING on top of the sea, displacing the water that it will be when it melts, and thus increasing world wide sea level when it breaks up NOT when it melts. This can occur overnight as oppose to decades or centuries for the Greenland Ice Sheet or the rest of the East Antarctic Ice Sheet. Together both would increase world wide sea level 40 feet (but most people believe only the West Antarctic Ice Sheet will Collapse, increasing world wide sea level 20 feet).
