Monday, 8 December 2014

Some Perspective on the Headlining Antarctic Ice Loss Trends

Guest post by Chip Knappenberger

The mainstream media has lit up the past few days with headlines of “alarming” news coming out of Antarctica highlighting new research on a more rapid than expected loss of ice from glaciers there.

But, as typical with blame-it-on-humans climate change stories, the coverage lacks detail, depth, and implication as well as being curiously timed.

We explain.

The research, by a team led by University of Cal-Irvine doctoral candidate Tyler Sutterley, first appeared online at the journal Geophysical Research Letters on November 15th, about two weeks before Thanksgiving. So why is it making headlines now? Probably because the National Aeronautics and Space Administration issued a press release on the new paper on December 2nd. Why wait so long? Because on December 1st, the United Nations kicked off its annual climate confab and the Obama administration is keen on orchestrating its release of scary-sounding climate stories so as to attempt to generate support for its executively commanded (i.e., avoiding Congress) carbon dioxide reduction initiatives that will be on display there. This also explains the recent National Oceanic and Atmospheric Administration speculation that 2014 is going to be the “warmest year on record”—another headline grabber—two months before all the data will be collected and analysed.

This is all predictable—and will essentially be unsuccessful.

Missing from the hype are the broader facts.

The new Sutterley research finds that glaciers in the Amundsen Sea Embayment region along the coast of West Antarctica are speeding up and losing ice. This is potentially important because the ice loss contributes to global sea level rise. The press coverage is aimed to make this sound alarming—“This West Antarctic region sheds a Mount Everest-sized amount of ice every two years, study says” screamed the Washington Post.

Wow! That sounds like a lot. Turns out, it isn’t.

The global oceans are vast. Adding a “Mount Everest-sized amount of ice every two years” to them results in a sea level rise of 0.02 inches per year. But “New Study Finds Antarctic Glaciers Currently Raise Sea Level by Two-Hundredths of an Inch Annually” doesn’t have the same ring to it.

Nor does the coverage draw much attention to the fact that the Amundsen Sea Embayment is but one of a great many watersheds across Antarctica that empty into the sea. A study published in Nature magazine back in 2012 by Matt King and colleagues provided a more comprehensive look at glacier behaviour across Antarctica. They did report, in agreement with the Sutterley findings, that glacial loss in the Amundsen Sea Embayment was rapid, but they also reported that for other large areas of Antarctica, ice loss was minimal or even negative (i.e., ice was accumulating). Figure 1, taken from the King paper, presents the broader and more relevant perspective (note that the Amundsen Sea Embayment is made up by the areas labelled 21 and 22 in Figure 1).

Figure 1. Best estimate of rate of ice loss from watershed across Antarctica. The Amundsen Sea Embayment, the focus of the Sutterley study, is encompassed by areas labelled 21 and 22 (taken from King et al., 2012).

We discussed the King and colleagues study in more detail when it first came out. We concluded:

So King and colleagues’ latest refinement puts the Antarctic contribution to global sea level rise at a rate of about one-fifth of a millimetre per year (or in English units, 0.71 inches per century).
    Without a significantly large acceleration—and recall the King et al. found none—this is something that we can all live with for a long time to come.

The strategically timed new findings being hyped this week do not change this conclusion.

References:

King, M., et al., 2012. Lower satellite-gravimetry estimates of Antarctic sea-level contribution. Nature, doi:10.1038/nature.

Sutterley, T.C., et al., 2014. Mass loss of the Amundsen Sea Embayment of West Antarctica from four independent techniques. Geophysical Research Letters, doi: 10.1002/2014GL06194


Paul C. “Chip” Knappenberger is the assistant director of the Center for the Study of Science at the Cato Institute, and coordinates the scientific and outreach activities for the Center.  He has over 20 years of experience in climate research and public outreach, including 10 years with the Virginia State Climatology Office and 15 years as the Research Coordinator for New Hope Environmental Services, Inc. Chip has published numerous papers in the major atmospheric science journals on global warming, hurricanes, precipitation changes, weather and mortality, and Greenland ice melt, among many other areas, and is a very popular presenter at climate conferences worldwide. He was also the administrator and a major contributor to World Climate Report, the original (and longest-running) blog on earth on climate change. He holds an M.S. and B.A. degrees in Environmental Sciences from the University of Virginia.
This post first appeared at the Cato at Liberty blog.

1 comment:

  1. Thanks Peter for copying and pasting this article. I tried to find this sort of info' elsewhere. Good to read Knappenberger is appropriately qualified to comment
    Peter

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