Edwards et al. (2021), and the associated linked article (see the attached image that shows SLR values beyond those cited in AR6 & click the image to enlarge), indicate that for risk-averse individuals the Antarctic Ice Sheet represents a major climate change risk:
Edwards, T. L., Nowicki, S., Marzeion, B., Hock, R., Goelzer, H., Seroussi, H., et al. (2021). Projected land ice contributions to twenty-first-century sea level rise. Nature, 593(7857), 74–82.
https://doi.org/10.1038/s41586-021-03302-yhttps://www.nature.com/articles/s41586-021-03302-yAbstract: "The land ice contribution to global mean sea level rise has not yet been predicted using ice sheet and glacier models for the latest set of socio-economic scenarios, nor using coordinated exploration of uncertainties arising from the various computer models involved. Two recent international projects generated a large suite of projections using multiple models, but primarily used previous-generation scenarios and climate models, and could not fully explore known uncertainties. Here we estimate probability distributions for these projections under the new scenarios using statistical emulation of the ice sheet and glacier models. We find that limiting global warming to 1.5 degrees Celsius would halve the land ice contribution to twenty-first-century sea level rise, relative to current emissions pledges. The median decreases from 25 to 13 centimetres sea level equivalent (SLE) by 2100, with glaciers responsible for half the sea level contribution. The projected Antarctic contribution does not show a clear response to the emissions scenario, owing to uncertainties in the competing processes of increasing ice loss and snowfall accumulation in a warming climate. However, under risk-averse (pessimistic) assumptions, Antarctic ice loss could be five times higher, increasing the median land ice contribution to 42 centimetres SLE under current policies and pledges, with the 95th percentile projection exceeding half a metre even under 1.5 degrees Celsius warming. This would severely limit the possibility of mitigating future coastal flooding. Given this large range (between 13 centimetres SLE using the main projections under 1.5 degrees Celsius warming and 42 centimetres SLE using risk-averse projections under current pledges), adaptation planning for twenty-first-century sea level rise must account for a factor-of-three uncertainty in the land ice contribution until climate policies and the Antarctic response are further constrained."
See also:
Title: "PROJECTED LAND ICE CONTRIBUTIONS TO 21ST-CENTURY SEA LEVEL RISE"
https://e3sm.org/projected-land-ice-contributions-to-21st-century-sea-level-rise/Extract: "The risk-averse storylines – based on the most sensitive ice sheet and climate models – produce the highest amounts of sea level rise for the given emissions scenarios and are shown by the set of pale time-series lines and the rightmost box-and-whisker plots in Figure 1.
Results from the study confirm that Antarctica remains a critical focus for reducing future uncertainty in sea level rise. The team’s high-end estimates for sea level rise from Antarctic land ice are more than twice as large as the ‘most likely’ estimate. This is largely due to substantial uncertainty in how strongly warm ocean waters will erode floating parts of the ice sheet from beneath."
Caption for the attached image: "Figure 1. Projected 2015-2100 land ice contribution to sea level, in centimeters (cm) of sea level equivalent (SLE), for a range of emissions scenarios. The various SSP1, 2, 3, and 5 scenarios refer to the Shared Socioeconomic Pathways while NDC stands for nationally determined contributions reflecting current climate pledges made under the Paris Agreement. (The aspirational Paris Agreement 1.5°C goal corresponds to the SSP1-19 scenario.) Solid lines and shaded regions show median and 5-95th percentile estimates, respectively. Pale solid lines denote 95th percentiles for risk-averse projections. Box-and-whiskers indicate 5, 25, 50, 75, 95th percentiles at 2100. (Figure edited after Edwards et al., 2021)"
Also, I note that version 2.0 of the Energy Exascale Earth System Model (E3SMv2) was formally frozen on September 13, 2021. Thus, we can soon expect journal articles regarding project support and data from the v2 DECK and historical simulations.