24 years tracking mass mortality events and marine heatwaves: when observations overcome the worst scenarios

The Mediterranean Sea is considered a climate change hotspot exhibiting warming rates and marine heatwaves (MHWs) events higher than in the global ocean. Among others, these conditions have already resulted in the onset of widespread mass mortality events (MMEs) across the Basin during the last 24 years. Since the first observation of an unprecedented MME in 1999, several international collaborative initiatives devoted to track the impacts and quences of MHWs and promoting solutions to support the resilience of coastal habitats in the face of climate change have been developed. Herein, we review how the Mediterranean scientific community has been tackling the challenges associated with MMEs in the Mediterranean. Focusing on the experience of building the T-MEDNet, a collaborative observation network dedicated to track climate change impacts, we present the main research issues and outcomes, and provide insights into new scientific avenues. p to now, through this collective effort, we have revealed that severe ecological impacts of MHWs are unfolding at an unexpectedly accelerated pace. This acceleration, along with the interacting effects of other climate change stressors, poses an unprecedented threat to the Mediterranean ecosystems’ health and functioning. In this context, it is critical to reinforce and upscale ongoing collaborative efforts at different levels aiming to increase the resolution of empirical observation networks, experimental studies, and interdisciplinary research. Such concerted efforts are essential for enhancing our ability to thoroughly comprehend and effectively manage the consequences of climate change and associated extreme climatic events such as marine heatwaves.