By Paul Homewood
Just to complete the situation with the Greenland Icesheet, I now have data for calving losses:
http://polarportal.dk/en/greenland/surface-conditions/
As I noted yesterday, the Surface Mass Balance of Greenland’s icesheet, as provided by DMI, does not include calving.
Below is an analysis of all ice sheet gains and losses since 1840 up to 2020, from Mankoff et al:
Annual average surface mass balance (blue line), marine mass balance (gray dashed), and their mass balance sum (black line).
https://essd.copernicus.org/preprints/essd-2021-131/essd-2021-131.pdf
The black line is the one to keep an eye on, as this nets SMB gains with losses from calving and basal melt (a small amount at the bottom of the glacier melts under pressure).
It is easy to recognise that net losses in the 1930s, 40s and 50s ran at a similar level to the last couple of decades. This is unsurprising since we know that temperatures in Greenland in those earlier decades were also similar to now.
I have updated the graph to December 2023 now, and added a 10-year average:
https://dataverse.geus.dk/dataset.xhtml?persistentId=doi:10.22008/FK2/OHI23Z
Since 2020, ice sheet losses have tended to decline, and there is a clear reduction in melt since the peak of 2012.
Periods of ice loss and gain are both associated with the AMO, so it is likely there will be a period of little or no loss when the AMO turns negative in due course.
In summary, ice losses are not accelerating, and are simply part of a much longer climate cycle, going back to the Little Ice Age and beyond. The idea that the icecap will quickly melt away is twaddle.