Reducing Warming to 1.5°C Cuts Sea-level Rise from All Land Ice in Half by 2100

Nature, May 5

In addition to the DeConto et al. (2021) study covered in our May 5 “Special Edition,” Nature also on Wednesday published a study consolidating many models to come up with their average estimate of sea-level rise from all land ice (both ice sheets, and glaciers). The study however only covered sea-level rise to 2100; and for Antarctica, largely could not include the additional features of the DeConto et al models such as marine ice cliff instability or calibration against observations and the paleo record, since the underlying models did not include them. This “averaged” study nevertheless estimates that halting global warming at 1.5°C would halve the contribution of melting land ice (all sources) to sea level rise by the year 2100, compared to current Paris emissions pledges. The main difference would come from Greenland and mountain glaciers: Greenland’s mass loss would be reduced by 70% in 2100, while that of mountain glaciers would be cut in half. Antarctica’s contribution to sea level rise varied widely in this averaged study; without dynamic processes included, they were generally lower than DeConto et al, but actually higher under high emissions scenarios in 2100. These two studies together emphasize the need to develop more models for Antarctica that take into account the complex processes observed there, given its potential for relatively rapid contributions to sea-level rise from the West Antarctic Ice Sheet in particular.

https://tc.copernicus.org/articles/15/1501/2021/

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