I wouldn’t be the only person to wonder whether the planet’s global land ice inventory has actually been growing for quite some time.  This is hinted at by formal government scientific disclosures, such as an article from as recently as 2017 at NASA [1].  The resource claims that the Antarctic ice sheet has been gaining more mass than it lost.

Given that Antarctica hosts over 90% of the world’s ice, the claim appears to support an additional conclusion that the world’s total ice mass is growing.   But one couldn’t tell from that resource, which quotes scientist Jay Zwally to assert that the main antarctic ice mass is growing even as precipitation has declined.

Keeping moisture as a main driver in mind, I find that hard to reconcile, unless tectonic rebound may account.  It is understood that several kilometers of ice can push the underlying land mass down, and when some ice is removed, the land can “bounce” back up (isostasy).  The study by Zwally et al., worked to account for that, via some approximations, and so I’m still interested to understand how the ice mass can increase without moisture additions, something which they term “dynamic thickening”.  If I had to guess, I would venture that they have under-estimated geostrophic atmospheric moisture contributions.

And although I’ve taken issue with a feature of their mass balancing exercises, I don’t have any other reason at this time to question their conclusion that approximately 70 to 150 Gt/a (gigatons per year) of frozen water are accumulating there.  The approximately hundreds-of-billions-of-tons of additional ice per year weighing down on Antarctica apparently does nothing to convince any scientist, media or policy person that perhaps global-warming panic is not warranted.  In fact, from their link, it is clear that NASA looks forward to ever greater (pencil-lead-thickness) precision in global ice and glacier measurement and bean-counting.  They apparently believe that the difference between a hundred-billion-tons and a hundred-billion-and-one tons, can swing the conclusion back into the proper hysterical framework.

On the other hand, I can continue to comb through existing resources to compare what was known about a century ago with what satellites and humans can see now.  I can easily find shrinking and growing glaciers.  In fact, I plan to feature some shrinking glaciers of geostrophic interest.  For now, it seems refreshing to explore the ones which appear to not be shrinking.  The featured image for example, compares maps of Mt. Ranier’s glacier mass in 1928 and now.  Both images were adapted from http://glaciers.research.pdx.edu/Glaciers-Washington. (No further citations for these images were provided at that page.)

A review of the two images will show some minor variation, but assuming both are nominally correct, I doubt any scientist would use these before-and-after graphics to reinforce climate-change-crisis-messaging.  For those scientists who must continue to alarm us however, I recommend they carry on  with features about glaciers which are shrinking, and ignore the rest.  The World Glacier Monitoring Service [2] is a good place to start, as it has also apparently done away with the time – honored practice of weighting one’s averages.   A later post will explore.

[1] https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses

which cites:

Volume 61Issue 230

Zwally, H.J., Li, J., Robbins, J.W., and Saba, J.L.  2015.  Mass gains of the Antarctic ice sheet exceed losses.  Journal of Glaciology.  Volume 61, Issue 230, pp. 1019-1036

[2] World Glacier Monitoring Service ICSU (WDS) – IUGG (IACS) – UNEP – UNESCO – WMO | 2017

 

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