News Brief by Kip Hansen — 16 January 2024 — 1100 words/5 mins
Antarctic ice melt has been an ongoing scientific controversy for more than a decade. Oddly, the warring parties are all at the same U.S. Federal Agency. The war, which involved salvos of papers between the NASA’s GRACE Ice Mass team and H. Jay Zwally and his team.
Here’s the background:
The current NASA Vital Signs of the Planet web page [NASA’s climate crisis propaganda section] for Ice Sheets carries this message boldly across the top one third of the page:
In 2021, I wrote about this issue in Antarctic Ice Mass — Alternate Sources, which featured these two contrasting images (but not together):
Here is today’s Vital Signs Antarctic Ice Sheets graphic:
It is important to remember that both the NASA’s GRACE Ice Mass team and Zwally et al. use the same data sets to determine their estimates of losses and gains. The differing results are then an indication of the different approaches to interpretation of that data, which may include biases.
NASA’s climate.gov doesn’t quite agree with Zwally et al. yet. But the Vital Signs graphic is for “Antarctic Ice Mass in Gts” . . . and that total ice mass has been level since turn of the century, with a lot of variation.
Compare Zwally’s 2021 estimate of -12 GT a year with the GRACE figure of -137 GT a year (in the two panel image, on the right). Zwally’s runs through the end of 2016.
Don’t think for a moment that Jay Zwally is some kook on the shady fringes of NASA – he is one of their top flight scientists and led the 2003 ICESat mission. He presented one of NASA’s famed MANIAC talks in 2019. And he has firmly stated that his Antarctic Ice Mass work is not a repudiation of climate science—it is just solid evidence that Antarctic Ice Mass is not plummeting as the Climate Crisis Team claims. (One might rightly ask why, then, don’t the creators of the Vital Signs Ice Sheets page present his results alongside of those of the GRACE team.)
So what’s the news?
The news is that some clever scientists — Collin M. Schohn, Neal R. Iverson, Lucas K. Zoe , Jacob R. Fowler, and Natasha Morgan-Witts — had decided that instead of blindly following the long-standing formulas for glacier ice flow, maybe they ought to find out, using real experiments, if those formulas actually reflect what happens in the physical universe where glaciers, ice under pressure, are flowing and melting. It took them ten years.
The story is covered in this SciTechDaily article: Glacier Experts Uncover Critical Flaw in Sea-Level Rise Predictions.
Disclosure: I am not a glaciologist. I know next to nothing about the physics of ice melting under pressure. Therefore, I report only what SciTechDaily says.
The article is a press release from Iowa State University (the by line is theirs). It says:
“New research shows temperate glacier ice flows more steadily than previously thought, leading to lower projections of sea-level rise.
Neal Iverson started with two lessons in ice physics when asked to describe a research paper about glacier ice flow that has just been published by the journal Science.
First, said the distinguished professor emeritus of Iowa State University’s Department of the Earth, Atmosphere, and Climate, there are different types of ice within glaciers. Parts of glaciers are at their pressure-melting temperature and are soft and watery.
That temperate ice is like an ice cube left on a kitchen counter, with meltwater pooling between the ice and the countertop, he said. Temperate ice has been difficult to study and characterize.
Second, other parts of glaciers have cold, hard ice, like an ice cube still in the freezer. This is the kind of ice that has typically been studied and used as the basis of glacier flow models and forecasts.
The new research paper deals with the former, said Iverson, a paper co-author and project supervisor.”
The press release is about Iverson’s new paper Linear-viscous flow of temperate ice (Schohn et al. 2025). (paywalled and too new for my usual paywall-work-arounds).
“The paper describes lab experiments and the resulting data that suggest a standard value within the “empirical foundation of glacier flow modeling” – an equation known as Glen’s flow law, named after the late John W. Glen, a British ice physicist – should be changed for temperate ice. …. The new value when used in the flow law “will tend to predict increases in flow velocity that are much smaller in response to increased stresses caused by ice sheet shrinkage as the climate warms,” Iverson said. That would mean models will show less glacier flow into oceans and project less sea-level rise.”
How much less? Can’t read the paper, 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 which was all contained in a temperature-controlled freezer:
The press release further states:
“Resetting n to 1.0
Glen’s flow law is written as: ε ̇ = Aτn.
The equation relates the stress on ice, τ, to its rate of deformation, ε ̇, where A is a constant for a particular ice temperature. Results of the new experiments show that the value of the stress exponent, n, is 1.0 rather than the usually assigned value of 3 or 4.
The authors wrote, “For generations, based on Glen’s original experiments and many subsequent experiments mostly on cold ice (-2 degrees C and colder), the value of the stress exponent n in models has been taken to be 3.0.” (They also wrote that other studies of the “cold ice of ice sheets” have placed n higher yet, at 4.0.)”
Most of us might want to check the Wiki for an explanation of Glen’s Flow Law. The key is that the exponent n is just that, an exponent and not a mere multiplier. Thus, the call to re-set that exponent to “1” makes a rather huge difference.
The Bottom Line:
New research shows temperate glacier ice flows more steadily, linearly and not exponentially, contrary to our previous understanding, and this leads to far lower projections of future sea-level rise due to any glacier melt in Greenland and Antarctica.
# # # # #
Author’ Comment:
We have to admire a group that spends ten years, working through all the failures and development, to discover something closer to the real-world truth about something as hard to measure as “glacier ice flow” – the flow of ice under tremendous pressures – and the melting that takes place.
Hopefully, we will see the findings translated into better, more reasonable and less hysterical projections of future sea level rise that might result from the melting of the glacier ice of Greenland and Antarctica.
Comments meant for me should begin with “Kip—“ or some such.
I can be reached by email at my first name at the domain i4.net.
Thanks for reading.
# # # # #
Related
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
