Low-End Probabilistic Sea-Level Projections

• Published in: Water
• Main Authors: Le Cozannet, Gonéri, Thiéblemont, Rémi, Rohmer, Jeremy, Idier, Déborah, Manceau, Jean-Charles, Quique, Robin
• Other Authors: Bureau de Recherches Géologiques et Minières (BRGM), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-17-CE03-0001,DELTA,Les deltas sous l'impact du changement global(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: RISE; CLIMATE; GREENLAND; UNCERTAINTY; SCENARIOS; GLACIERS; MODEL; sea-level rise; projections; probabilistic; ANTARCTIC ICE-SHEET; VERTICAL LAND MOTION; SURFACE MASS-BALANCE; [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology; Antarctic; Greenland; Antarc*; Ice Sheet
• Online Access: https://hal.science/hal-02380970; https://hal.science/hal-02380970/document; https://hal.science/hal-02380970/file/hal-02380970.pdf; https://doi.org/10.3390/w11071507

International audience In the area of sea-level rise, recent research has focused on assessing either likely or high end future sea levels, but less attention has been given to low-end sea-level projections, exploring best-case potential sea-level changes and providing the basis for estimating minimum adaptation needs. Here, we provide global and regional probabilistic sea-level projections using conservative projections of glaciers and ice-sheets melting and a selection of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) delivering moderate thermal expansion. Our low-end sea-level projections are higher than previously estimated because they rely on modeling outcomes only, and do not add any expert judgement, aiming essentially at delivering more realistic upper tails. While there are good reasons to believe that our projections are excessively optimistic, they can be used as low-end sea-level projections in order to inform users with low aversion to uncertainty. Our low-end sea-level projection exceeds 0.5 m along most inhabited coasts by 2100 for business as usual greenhouse gas emissions (RCP8.5), which is relevant for adaptation practitioners as long as efficient climate change mitigation policies are not implemented. This means that without efficient climate mitigation, an acceleration of sea-level rise can hardly be avoided during the 21st century.