Ross Ice Shelf - World's Largest - Melting At Rate 10X Global Average For Ice Shelves

[hatrack]

The world’s largest ice shelf is melting 10 times faster than the average ice shelf due to warming surface water, according to a new report.

Researchers studying data taken at Antarctica’s Ross Ice Shelf over the last four years reported on Monday that warming ocean water that’s heated by the sun is causing the rapid melting that intensifies risks of long-term rising sea levels. The findings, which were discovered in part by researchers at the University of Cambridge, were published in the journal Nature Geoscience.

“The stability of ice shelves is generally thought to be related to their exposure to warm deep ocean water, but we’ve found that solar heated surface water also plays a crucial role in melting ice shelves,” the report’s leading author, Craig Stewart from the National Institute of Water and Atmospheric Research in New Zealand, said in a release. Stewart conducted the work while a Ph.D. student at the University of Cambridge.

The findings may be particularly bad news, as the melting ice shelf, which is about the size of France, stabilizes the West Antarctic ice sheet and blocks ice that flows into it from some of the world’s largest glaciers. Should it weaken, it could significantly increase the risk of instability in surrounding glaciers, including those more than 500 miles away, and lead to rising sea levels of several meters or more, the researchers warned.

EDIT

https://www.huffpost.com/entry/ross-ice-shelf-melting-solar-heated-water_n_5cc87812e4b07c9a4cea2019

[nitpicker]

1. Link to BBC

https://www.bbc.com/news/science-environment-48107497

[OKIsItJustMe]

2. The Huffington Post got it wrong

https://www.cam.ac.uk/research/news/rapid-melting-of-the-worlds-largest-ice-shelf-linked-to-solar-heat-in-the-ocean

While the Ross Ice Shelf is considered to be relatively stable, the new findings show that it may be more vulnerable than thought so far. The point of vulnerability lies in the fact that that solar heated surface water flows into the cavity near a stabilising pinning point, which could be undermined if basal melting intensifies further. The study shows that melting in this specific region is 10 times higher than the average melt rate expected for the ice shelf as a whole.

https://www.nature.com/articles/s41561-019-0356-0

Abstract

Ice–ocean interactions at the bases of Antarctic ice shelves are rarely observed, yet have a profound influence on ice sheet evolution and stability. Ice sheet models are highly sensitive to assumed ice shelf basal melt rates; however, there are few direct observations of basal melting or the oceanographic processes that drive it, and consequently our understanding of these interactions remains limited. Here we use in situ observations from the Ross Ice Shelf to examine the oceanographic processes that drive basal ablation of the world’s largest ice shelf. We show that basal melt rates beneath a thin and structurally important part of the shelf are an order of magnitude higher than the shelf-wide average. This melting is strongly influenced by a seasonal inflow of solar-heated surface water from the adjacent Ross Sea Polynya that downwells into the ice shelf cavity, nearly tripling basal melt rates during summer. Melting driven by this frequently overlooked process is expected to increase with predicted surface warming. We infer that solar heat absorbed in ice-front polynyas can make an important contribution to the present-day mass balance of ice shelves, and potentially impact their future stability.

More here: https://democraticunderground.com/1127126968