| Title | A high-end estimate of sea level rise for practitioners |
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| Author | van de Wal, R S W ; Nicholls, R; Behar, D; McInnes, 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; Jenkins, A; LeCozannet, G; 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 |
| Source | Earth's Future vol. 10, issue 11, 2022 p. 1-24, https://doi.org/10.1029/2022EF002751  Open Access |
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| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210469 |
| Publisher | AGU |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | environmental geology; Nature and Environment; Science and Technology; sea level changes; sea level fluctuations; ice; climate; climate effects; Estimates; Decision making |
| Illustrations | tables; schematic models |
| Program | Climate Change Geoscience Coastal Infrastructure |
| Released | 2022 10 22 |
| Abstract | 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. |
| Summary | (Plain Language Summary, not published)
Sea-level projections are produced by summing the contributions from a number of sources, including ocean warming, ice sheet and glacier melt, and a
number of other smaller effects. Most of the contributions are relatively well understood and can be modelled with their uncertainties, but the future state of large ice sheets, especially in Antarctica, is less well known and introduces considerable
uncertainty into estimates of the probable largest, or high-end, projections of global sea-level. This paper directly addresses this problem by considering the probable largest contributions from each of the sources, and provides an approach that can
be updated in the future as additional information becomes available and understanding is improved. The results indicate that for a global warming level of +2K in 2100 relative to pre-industrial values the high-end global sea-level rise (SLR)
estimates are up to 1.0 m in 2100 and 3 m in 2300. For +5K warming level by 2100 SLR up to 1.6 m and up to 11 m in 2300. These results indicate that there are strong benefits to robust mitigation of carbon emissions. Even under relatively strong
carbon mitigation, however, global sea level is projected to continue to rise, in agreement with the recently released Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC). |
| GEOSCAN ID | 329326 |
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