Friday, May 1, 2015

Antarctic Ice Loss Accelerating

One of the false arguments deniers make is that polar ice is increasing, thus negating claims the world is getting warmer. Their line of reasoning is that the amount of Antarctic sea ice is increasing, even increasing to record levels, and this means the ice in the polar regions is increasing. Of course, the problem with that claim is that it ignores the Arctic sea ice, the Greenland Ice Sheet and the Antarctic land ice, all of which are decreasing in extent. In other words, the ice in the polar regions is decreasing, is decreasing at both ends of the planet and is decreasing at alarming rates. Now, a new report indicates the bad news is getting worse.The rate of loss is increasing.

Researchers at Princeton University used gravity data collected by the GRACE satellite to determine the East Antarctic Ice Sheet increased in mass over the last 10 years, but the Western Antarctic Ice Sheet (WAIS) lost twice as much ice as the eastern sheet gained. The average net loss for the whole continent was 92 billion tons of ice per year. The data showed WAIS lost 121 billion tons of ice in 2008 and this level increased by 18 billion tons per year every year until it was losing twice as much in 2014. Frederick Simons, one of the coauthors, stated,
"A decade of gravity analysis alone cannot force you to take a position on this ice loss being due to anthropogenic global warming. All we have done is take the balance of the ice on Antarctica and found that it is melting -- there is no doubt. But with the rapidly accelerating rates at which the ice is melting, and in the light of all the other, well-publicized lines of evidence, most scientists would be hard pressed to find mechanisms that do not include human-made climate change."
GRACE measures the amount of gravitational attraction which is the result of the amount of mass present. By measuring the mass over a period of time, the data shows how the mass is changing. Simply measuring the volume could be misleading because snow and ice can compress under the enormous weight of thousands of feet of ice. There is no denying the gravity data, though.

The data, the evidence and the inescapable conclusion explains why deniers use the false argument and ignore the total amount of ice loss.  But, it is getting increasingly more difficult to ignore the reality.

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