Kip Hansen's News Brief – January 16, 2024 – 1100 words/5 minutes
Melting Antarctic glaciers have been an ongoing scientific controversy for more than a decade. Oddly, both warring parties are in the same U.S. federal agency. This battle involves a paper battle between NASA's GRACE Ice Mass team and H. Jay Zwally and his team.
Here's the background:
Current NASA Earth Vital Signs webpage [NASA’s climate crisis propaganda section] for Ice Sheets boldly conveys this message in the top third of the page:
In 2021, I am Antarctic Ice—Alternative Sources, It contains these two comparison images (but not together):
This is Today's Antarctic Ice Sheet Vital Signs Chart:
It is important to remember that NASA's GRACE Ice Mass team and Zwally et al. Use the same data set to determine their estimates of losses and gains. Different results indicate different ways of interpreting the data, which may include bias.
NASA's Climate.gov disagrees with Zwally et al. However. But the vital signs graphics are suitable for “Antarctic Ice Gts”. . . Total ice volume has remained constant since the turn of the century, but there is considerable variation.
Compare Zwally's 2021 estimate of -12 GT per year with the GRACE figure of -137 GT per year (in the two panels on the right). Zwally's operates until the end of 2016.
Don't think that Jay Zwally is a fringe NASA weirdo. He is one of NASA's top flight scientists and led the 2003 ICESat mission. He delivered one of NASA's famous MANIAC lectures in 2019. A sharp decline as claimed. (One might rightly ask, then, why the creator of the Vital Signs Icefield page does not present his results alongside those of the GRACE team.)
So any news?
Word is that some smart scientists—Collin M. Schohn, Neal R. Iverson, Lucas K. Zoe, Jacob R. Fowler, and Natasha Morgan-Witts—have decided not to blindly follow the long-standing glacier ice flow formula. Maybe they should run real experiments to find out whether these formulas actually reflect what's happening in the physical universe, where glaciers, ice under pressure, are flowing and melting. It took them ten years.
The story is covered here Science and Technology Daily article: Glacier experts find critical flaw in sea level rise forecasts.
Disclosure: I am not a glaciologist. I knew next to nothing about the physics of ice melting under pressure. Therefore, I only report Science and Technology Daily explain.
This article is a press release from Iowa State University (signature is theirs). It says:
“New research shows that ice flow from temperate glaciers is more stable than previously thought, leading to lower projections of sea level rise.
Neil Iverson When asked to describe a research paper on glacial ice flows that had just been published in Science, I started with two lessons in ice physics.
First, the famous professor emeritus said Department of Earth, Atmosphere and Climate, Iowa State Universitythere are different types of ice within the glacier. Parts of the glacier are at pressure melting temperatures and are soft and watery.
This temperate ice is like ice cubes left on a kitchen counter, with meltwater collecting between the ice and the countertop, he said. Temperate ice is difficult to study and characterize.
Second, other parts of the glacier have cold, hard ice, like ice cubes in a refrigerator. This ice is commonly studied and used as the basis for glacier flow models and predictions.
The new research paper involves the former, said Iverson, co-author and project director.
Press Release Is About Iverson's New Paper Linear viscous flow in temperate ice (Schohn et al., 2025). (Paywall, too new for my usual paywall workaround).
“This paper describes laboratory experiments and the resulting data showing that standard values in the 'Empirical Basis of Glacier Flow Models' – an equation known as Glenn's flow law, after the late British Ice Named after physicist John W. Glenn – should have been changed to temperate ice… Iverson said that when using new values in the flow laws, “tends to predict an increase in flow velocity that is much smaller. “In response to increased pressure caused by shrinking ice sheets as the climate warms.” This means models will show less glaciers flowing into the ocean and predict less sea level rise.
How much less? I can’t read newspapers, so I don’t know. [If anyone has access to the paper here, I’d love a copy].
But here is Iverson's sketch of the experimental equipment, all contained in a temperature-controlled refrigerator:
The press release further states:
“reset n to 1.0
Glenn's flow law can be written as: ε ̇ = inn.
This equation connects the stress τ on the ice to its deformation rate, e ̇where A is a constant for a specific ice temperature. The results of the new experiment show the value of the stress index, nis 1.0, rather than the normally specified values of 3 or 4.
“For generations, the value of the stress exponent n in models has been taken to be 3.0, based on Glen's original experiments and many subsequent experiments, mostly conducted on cold ice (-2 degrees Celsius and below),” the authors write. (They also write that other studies of ice sheet cold ice have shown n higher, at 4.0.
Most of us might want to check out the Wiki for an explanation Glenn's flow law. The key is the index n That's it, an exponent and not just a multiplier. Therefore, a call that resets the index to “1” makes a considerable difference.
Bottom line:
New research shows that temperate glacial ice flows in a more steady, linear rather than exponential pattern, contrary to our previous understanding, leading to much lower projections of future sea level rise from melting glaciers in Greenland and Antarctica.
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Author comments:
We have to admire such a team. They spent ten years, experienced all the failures and developments, and discovered some truths closer to the real world, about something as difficult to measure as “glacier ice flow”-ice is huge in Flow under pressure—and the melting that occurs.
Hopefully we'll see these findings translate into better, more reasonable, and less hysterical predictions of future sea level rise that could result from melting glaciers in Greenland and Antarctica.
Comments to me should start with “Kip-” or something similar.
You can contact me via email at the i4.net domain.
Thank you for reading.
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