A High‐End Estimate of Sea Level Rise for Practitioners

• Published in: Earth's Future
• Main Authors: van de Wal, R, S W, Nicholls, R, J, Behar, D., Mc Innes, K., Stammer, D., Lowe, J, A, Church, J, A, Deconto, R., Fettweis, X., Goelzer, H., Haasnoot, M., Haigh, I, D, Hinkel, J., Horton, B, P, James, T, S, Jenkins, A., Le Cozannet, Gonéri, Levermann, A., Lipscomb, W, H, Marzeion, B., Pattyn, F., Payne, A, J, Pfeffer, W, T, Price, S, F, Seroussi, H., Sun, S., Veatch, W., White, K.
• Other Authors: Institute for Marine and Atmospheric Research Utrecht (IMAU), Universiteit Utrecht / Utrecht University Utrecht, Tyndall Centre for Climate Change Research, University of East Anglia Norwich (UEA), San Francisco Public Utilities Commission, Climate Change Research Centre Sydney (CCRC), University of New South Wales Sydney (UNSW), Institut für Meereskunde Hamburg, Universität Hamburg (UHH), Met Office Hadley Centre (MOHC), United Kingdom Met Office Exeter, University of Massachusetts Amherst (UMass Amherst), University of Massachusetts System (UMASS), Laboratory of Climatology, Université de Liège, Global Climate Forum e.V., Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey New Brunswick (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Earth Observatory of Singapore (EOS), Nanyang Technological University Singapour, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), University of Bremen, Université libre de Bruxelles (ULB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarc*; Antarctica; Ice Shelf
• Online Access: https://brgm.hal.science/hal-03845598; https://brgm.hal.science/hal-03845598/document; https://brgm.hal.science/hal-03845598/file/Earth%20s%20Future%20-%202022%20-%20Wal%20-%20A%20High%E2%80%90End%20Estimate%20of%20Sea%20Level%20Rise%20for%20Practitioners.pdf; https://doi.org/10.1029/2022EF002751

International audience Sea level rise (SLR) is a long-lasting consequence of climate change because global anthropogenic warming takes centuries to millennia to equilibrate for the deep ocean and ice sheets. SLR projections based on climate models support policy analysis, risk assessment and adaptation planning today, despite their large uncertainties. The central range of the SLR distribution is estimated by process-based models. However, risk-averse practitioners often require information about plausible future conditions that lie in the tails of the SLR distribution, which are poorly defined by existing models. Here, a community effort combining scientists and practitioners builds on a framework of discussing physical evidence to quantify highend global SLR for practitioners. The approach is complementary to the IPCC AR6 report and provides further physically plausible high-end scenarios. High-end estimates for the different SLR components are developed for two climate scenarios at two timescales. For global warming of +2°C in 2100 (RCP2.6/SSP1-2.6) relative to pre-industrial values our high-end global SLR estimates are up to 0.9 m in 2100 and 2.5 m in 2300. Similarly, for a (RCP8.5/SSP5-8.5), we estimate up to 1.6 m in 2100 and up to 10.4 m in 2300. The large and growing differences between the scenarios beyond 2100 emphasize the long-term benefits of mitigation. However, even a modest 2°C warming may cause multi-meter SLR on centennial time scales with profound consequences for coastal areas. Earlier high-end assessments focused on instability mechanisms in Antarctica, while here we emphasize the importance of the timing of ice shelf collapse around Antarctica. This is highly uncertain due to low understanding of the driving processes. Hence both process understanding and emission scenario control high-end SLR. Plain Language Summary Taking a co-production approach between scientists and practioners, we provide high-end sea level rise (SLR) estimates for practitioner application based on an expert ...