Four new studies in prestigious journals show Antarctic ice shelf as stable as ever.
Hat-tip: EIKE Klimaschau
Andreasen et al (2023) finds net gain
A study by Julia R. Andreasen and colleagues looked at the changes in ice shelves, Antarctic-wide, using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data from 2009 to 2019.
Image: Andreasen et al (2023)
They found that over the period 2009-2019, overall Antarctic ice shelf area grew by 5305 km2.
18 ice shelves retreated somewhat and 16 larger shelves grew in terms of area. “Our observations show that Antarctic ice shelves gained 661 Gt of ice mass over the past decade,” the scientists summarized.
Banwell et al (2023) meltwater volume dropped
Another new paper by Banwell et al published in the journal Geophysical Research Letters looked at the duration and amount of surface ice melting on Antarctica’s ice shelves from 1980 to 2021, using microwave satellite data the snow model SNOWPACK.
Result: They found that the highest meltwater volumes were produced on the Peninsula, reaching a peak in the 1992/1993 and 1994/1995, and that SNOWPACK calculated “a small, but significant, decreasing trend in both annual melt days and meltwater production volume over the 41 years.”
Another study published in Nature authored by Frazer et al (2023) found that although West Antarctica – particularly from Pine Island and Thwaites glaciers – has seen dramatic ice losses in recent decades, projections of their future rate are confounded by limited observations.
Also, looking at the period 2003 and 2015, they found rates of glacier retreat and acceleration to be extensive along the Bellingshausen Sea coastline, but slowed along the Amundsen Sea.
The authors conclude: Our results provide direct observations that the pace, magnitude and extent of ice destabilization around West Antarctica vary by location, with the Amundsen Sea response most sensitive to interdecadal atmosphere-ocean variability.
Baico et al (2023) 35 meters thinner thousands of years ago
Finally, in yet another new published paper by Baico et al (2023), the authors looked at subglacial bedrock cores show that the West Antarctic Ice Sheet (WAIS) between Thwaites and Pope glaciers and found it “was at least 35 m thinner than present in the past several thousand years and then subsequently thickened.”
Moreover: “A past episode of ice sheet thinning that took place in a similar, although not identical, climate was not irreversible. We propose that the past thinning–thickening cycle was due to a glacioisostatic rebound feedback, similar to that invoked as a possible stabilizing mechanism for current grounding line retreat, in which isostatic uplift caused by Early Holocene thinning led to relative sea level fall favoring grounding line advance.”