Online seminar by Prof. Thomas L. Frölicher from University of Bern
27 April 2022
KST 16:00 – 17:00
Extreme events, i.e., the normally rare occurrences when a system is far outside its norm, severely impact organisms and ecosystem on land. Yet, in comparison, our understanding of such extreme events in the ocean is generally poor. This is especially the case for ocean biogeochemical extremes, while the knowledge on marine heatwaves has grown rapidly in recent years. With trends in ocean warming, acidification, deoxygenation, and surface nutrient concentrations projected to continue for decades, marine heatwaves and ocean biogeochemical extreme events are likely to intensify, occur more often, persist for longer, and extend over larger regions. Of particular concern are compound events, i.e., when conditions are extreme concurrently for multiple properties. Compound extremes can lead to especially severe impacts, since the individual properties may interact synergistically. Here we combine observations with large ensemble simulations of Earth system models to assess the spatial characteristics, underlying drivers and trends in ocean extremes and compound events and their impacts on marine ecosystems, with a focus on compound marine heatwaves and ocean acidity extremes. Since the conditions exhibited by today’s extreme events are a harbinger of what may become ‘normal’ in the future, our results may help to better understand the response of marine organisms and ecosystems to future climate change.