Global-scale changes in extreme ocean wave events due to anthropogenic warming

Extreme ocean waves are often primary drivers of coastal flooding/erosion at various time-scales1. Understanding future changes in these events to global warming is of socio-economic and environmental relevance. However, our current knowledge on changes in high-frequency (i.e. events occurring multiple times a year) extreme wave events are largely unknown despite being strongly linked to coastal hazards over decision-relevant time-scales. Here, we present global climate-modeling evidence of projected changes in a set of wave indices describing the frequency of such events using the most comprehensive multi-method/model ensemble. We find changes in persistent storm wave events of up to ~50-100% for global warming exceeding 2°C; a nearly double than for global warming below 2°C when globally-integrated. Changes to extreme wave events exhibit strong inter-hemispheric asymmetry, with ~30-40% of the global ocean exhibiting robust changes for warming above 2°C. In general, we find an increase across the tropics and high latitudes of the Southern Hemisphere, and a widespread decrease across most of the Northern Hemisphere. We find that patterns of projected changes in these storm wave events are remarkably consistent with their historical response to the positive/negative phase of the Southern Annular Mode (SAM) and El Nino-Southern -Oscillation (ENSO) in these regions, respectively. Our findings highlight that many countries of low-adaptive capacity will likely face increasing exposure to much more frequent extreme wave events every year in the future.

MORIM Joao;  VITOUSEK Sean;  HEMER Mark;  REGUERO Borja;  ERIKSON Li;  CASAS-PRAT Mercè;  WANG Xiaolan;  SEMEDO Alvaro;  MORI Nobuhito;  SHIMURA Tomoya;  MENTASCHI Lorenzo;  TIMMERMANS Ben; 

2022-09-08

IOP PUBLISHING LTD

JRC120960

1748-9326 (online),   

https://iopscience.iop.org/article/10.1088/1748-9326/ac1013,    https://publications.jrc.ec.europa.eu/repository/handle/JRC120960,   

10.1088/1748-9326/ac1013 (online),