Robustness and uncertainties in global multivariate wind-wave climate projections

Morim, Joao and Hemer, Mark and Wang, Xiaolan L. and Cartwright, Nick and Trenham, Claire and Semedo, Alvaro and Young, Ian and Bricheno, Lucy and Camus, Paula and Casas-Prat, Mercè and Erikson, Li and Mentaschi, Lorenzo and Mori, Nobuhito and Shimura, Tomoya and Timmermans, Ben and Aarnes, Ole and Breivik, Øyvind and Behrens, Arno and Dobrynin, Mikhail and Menendez, Melisa and Staneva, Joanna and Wehner, Michael and Wolf, Judith and Kamranzad, Bahareh and Webb, Adrean and Stopa, Justin and Andutta, Fernando (2019) Robustness and uncertainties in global multivariate wind-wave climate projections. Nature Climate Change, 9 (9). pp. 711-718. ISSN 1758-678X (https://doi.org/10.1038/s41558-019-0542-5)

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Abstract

Understanding climate-driven impacts on the multivariate global wind-wave climate is paramount to effective offshore/coastal climate adaptation planning. However, the use of single-method ensembles and variations arising from different methodologies has resulted in unquantified uncertainty amongst existing global wave climate projections. Here, assessing the first coherent, community-driven, multi-method ensemble of global wave climate projections, we demonstrate widespread ocean regions with robust changes in annual mean significant wave height and mean wave period of 5–15% and shifts in mean wave direction of 5–15°, under a high-emission scenario. Approximately 50% of the world’s coastline is at risk from wave climate change, with ~40% revealing robust changes in at least two variables. Furthermore, we find that uncertainty in current projections is dominated by climate model-driven uncertainty, and that single-method modelling studies are unable to capture up to ~50% of the total associated uncertainty.