Characterizing marine temperature extremes and their impacts under climate change: the CAREHeat project

The project “deteCtion and threAts of maRinE Heat waves – CAREHeat”, funded by ESA in the framework of the Ocean Health initiative, aims at advancing the understanding of marine heatwaves (MHWs) processes, including the associated physical processes and biogeochemical responses at the global scale. This is achieved by integrating long-term satellite-based climate data records with model-based datasets and high quality in situ observations of key parameters, such as temperature and carbon concentration.

In the frame of the project we assess the sensitivity of standard detection approaches to methodological choices, which we find to be significant across major ocean basins. Dependence on the dataset choices is also a matter of concern, as they can contribute to spread in the detection results. 

Furthermore, we study processes leading to persistent heatwave conditions for selected case studies, such as the Mediterranean Sea, in the last decades. This type of events can have cascading effects on marine ecosystems, such as phytoplankton communities and higher trophic levels, therefore is of paramount importance to understand them and anticipate them to aid adaptation and mitigation.

Perspectives on multivariate compound extremes, whereby heatwaves are associated with e.g. increasing ocean acidification, will also be discussed, to try and disentangle the effects of anthropogenic warming from the modulation due to natural climate variability. 

Further details on the project outcomes can be found at the associated website (https://careheat.org/) and broader context is provided by the ESA Ocean Science Cluster (https://eo4society.esa.int/communities/scientists/esa-ocean-science-cluster/). Key results from the project, such as the heatwave atlas, are publicly disseminated to facilitate research and increase awareness on this pressing problem.