Past Ice Sheet Collapsed at Rates of 50-600 Meters Per Day, Under Conditions Similar to the WAIS Today

Nature, 06 April 2023

A study of the earlier great ice sheet covering Scandinavia has found that when it collapsed about 19,000 years ago, it did so at rates up to 600 meters per day; far faster than anything measured by satellite data over the past 50 years. Indeed the slowest rate of collapse of this ice sheet, recorded in daily detail in the seabed sediment pressed down by the ice sheet off today’s Norwegian coast, was 50 meters per day, nearly double that of the fastest observed to-date in the satellite record (for Pope Glacier, West Antarctica, at 30 meters/day). Looking towards current seabed topography under parts of the West Antarctic Ice sheet, especially Thwaites Glacier, the scientists note similar conditions that might allow an equally fast rate of collapse. Through this documented example from the past, these findings strengthen previous studies warning that in a warming world, collapse and resulting sea-level rise can occur unexpectedly rapidly once triggered. To prevent or slow this outcome in the WAIS, which alone holds 3-4 meters of sea-level rise, immediate reductions in fossil fuel emissions are needed, in accordance with the lowest-emission feasible pathways documented in the IPCC AR6 Synthesis Report.

https://www.nature.com/articles/s41586-023-05876-1