Bounding probabilistic sea-level projections within the framework of the possibility theory

• Published in: Environmental Research Letters
• Main Authors: Le Cozannet, Gonéri, Manceau, Jean-Charles, Rohmer, Jeremy
• Other Authors: Bureau de Recherches Géologiques et Minières (BRGM), BRGM
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Antarc*; Antarctica; Greenland
• Online Access: https://brgm.hal.science/hal-01440548; https://brgm.hal.science/hal-01440548/document; https://brgm.hal.science/hal-01440548/file/Le_Cozannet_et_al_2017_Environ._Res._Lett._12_014012.pdf; https://doi.org/10.1088/1748-9326/aa5528

International audience Despite progresses in climate change science, projections of future sea-level rise remain highly uncertain, especially due to large unknowns in the melting processes affecting the ice-sheets in Greenland and Antarctica. Based on climate-models outcomes and the expertise of scientists concerned with these issues, the IPCC provided constraints to the quantiles of sea-level projections. Moreover, additional physical limits to future sea-level rise have been established, although approximately. However, many probability functions can comply with this imprecise knowledge. In this contribution, we provide a framework based on extra-probabilistic theories (namely the possibility theory) to model the uncertainties in sea-level rise projections by 2100 under the RCP 8.5 scenario. The results provide a concise representation of uncertainties in future sea-level rise and of their intrinsically imprecise nature, including a maximum bound of the total uncertainty. Today, coastal impact studies are increasingly moving away from deterministic sea-level projections, which underestimate the expectancy of damages and adaptation needs compared to probabilistic laws. However, we show that the probability functions used so-far have only explored a rather conservative subset of sea-level projections compliant with the IPCC. As a consequence, coastal impact studies relying on these probabilistic sea-level projections are expected to underestimate the possibility of large damages and adaptation needs.