ExTaSea SIGNED

Project "ExTaSea" data sheet

The following table provides information about the project.

 Partnership

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Map

 Project objective

Sea-level rise is a major societal concern, with potential impacts on population, infrastructure and coastal environments. Coastal defence and adaptation strategies are highly dependent upon our ability to understand and predict sea-level variability, including extreme sea levels. Quantifying the upper tail probability of sea level – i.e., the risk of extremes - is therefore of high socio-economic relevance. Current projections suggest a low probability of polar ice-sheet decay scenarios, but they cannot be ruled out. Such scenarios are poorly parameterized and/or associated with large uncertainties in current projections. The ExTaSea project will address two sources of uncertainty in current projections of future sea-level: (1) our understanding of the system and, (2) the degree to which we can simulate natural variability. ExTaSea will do this by producing well quantified natural bounds on both the rate and magnitude of sea level rise (objective 1) and probability distributions that include specific information on high-end extremes for global mean and regional sea levels (objective 2). These will contribute to our understanding of these sources of uncertainty and will form the basis for policy-relevant extreme sea-level scenarios (objective 3) that account for the dynamic response of the ice sheets to climate forcing. ExTaSea will produce statistical distributions by: (1) collating and quality checking already available geological data from past time intervals of the last 200,000 years that are useful analogues for future change; (2) novel statistical techniques (e.g., modified Bayesian partition modelling) and (3) modelling of solid Earth deformation processes (GIA) that will allow absolute magnitudes of sea levels to be determined. As the geological record integrates all processes, the statistical distributions on the natural bounds of sea-level will include the high-impact (extreme) tail associated with mass loss from the polar ice sheets.