Illustrative multi-centennial projections of global mean sea-level rise and their application

• Published in: Earth's Future
• Main Authors: Turner, Fiona E., Malagon Santos, Victor, Edwards, Tamsin L., Slangen, Aimée B. A., Nicholls, Robert J., Le Cozannet, Gonéri, O’Neill, James, Adhikari, Mira
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Antarc*; Antarctic; Ice Sheet
• Online Access: https://ueaeprints.uea.ac.uk/id/eprint/93928/; https://ueaeprints.uea.ac.uk/id/eprint/93928/1/Earth_s_Future_2023_Turner_Illustrative_Multi_Centennial_Projections_of_Global_Mean_Sea_Level_Rise_and_Their.pdf; https://doi.org/10.1029/2023EF003550

We produce projections of global mean sea-level rise to 2500 for low and medium emissions scenarios (Shared Socioeconomic Pathways SSP1-2.6 and SSP2-4.5) relative to 2020, based on extending and combining model ensemble data from current literature. We find that emissions have a large effect on sea-level rise on these long timescales, with [5, 95]% intervals of [0.3, 4.3]m and [1.0, 7.6]m under SSP1-2.6 and SSP2-4.5 respectively, and a difference in the 95% quantile of 1.6 m at 2300 and 3.3 m at 2500 for the two scenarios. The largest and most uncertain component is the Antarctic ice sheet, projected to contribute 5%–95% intervals of [−0.1, 2.3]m by 2500 under SSP1-2.6 and [0.0, 3.8]m under SSP2-4.5. We discuss how the simple statistical extensions used here could be replaced with more physically based methods for more robust predictions. We show that, despite their uncertainties, current multi-centennial projections combined into multi-study projections as presented here can be used to avoid future “lock-ins” in terms of risk and adaptation needs to sea-level rise.