Mass loss of the Antarctic ice sheet until the year 3000 under a sustained late-21st-century climate

• Published in: Journal of Glaciology
• Main Authors: Christopher Chambers, Ralf Greve, Takashi Obase, Fuyuki Saito, Ayako Abe-Ouchi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2022
• Subjects: Antarctic glaciology; ice and climate; ice-sheet modelling; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Antarctic; The Antarctic; East Antarctica; West Antarctica; West Antarctic Ice Sheet; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2021.124; https://doaj.org/article/166d45e509f6497cb69da9a958984a68

Ice-sheet simulations of Antarctica extending to the year 3000 are analysed to investigate the long-term impacts of 21st-century warming. Climate projections are used as forcing until 2100 and afterwards no climate trend is applied. Fourteen experiments are for the ‘unabated warming’ pathway, and three are for the ‘reduced emissions’ pathway. For the unabated warming path simulations, West Antarctica suffers a much more severe ice loss than East Antarctica. In these cases, the mass loss amounts to an ensemble average of ~3.5 m sea-level equivalent (SLE) by the year 3000 and ~5.3 m for the most sensitive experiment. Four phases of mass loss occur during the collapse of the West Antarctic ice sheet. For the reduced emissions pathway, the mean mass loss is ~0.24 m SLE. By demonstrating that the consequences of the 21st century unabated warming path forcing are large and long term, the results present a different perspective to ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6). Extended ABUMIP (Antarctic BUttressing Model Intercomparison Project) simulations, assuming sudden and sustained ice-shelf collapse, with and without bedrock rebound, corroborate a negative feedback for ice loss found in previous studies, where bedrock rebound acts to slow the rate of ice loss.