Recent marine heat waves have caused devastating impacts on marine ecosystems. Substantial progress in understanding past and future changes in marine heat waves and their risks for marine ecosystems is needed to predict how marine systems, and the goods and services they provide, will evolve in the future.
Extreme climate and weather events shape the structure of terrestrial biological systems and affect the biogeochemical functions and services they provide for society in a fundamental manner. There is overwhelming evidence that atmospheric heat waves over land are changing under global warming, increasing the risk of severe, pervasive and in some cases irreversible impacts on natural and socio-economic systems. In contrast, we know little how extreme events in the ocean, especially those associated with warming will change under global warming, and how they will impact marine organisms. This knowledge gap is of particular concern as some of the recent observed marine heat waves (MHWs) demonstrated the high vulnerability of marine organisms and ecosystems services to such extreme climate events.