Climate Change Impacts on the Adriatic Sea: Integrating Sea State Indicators and River Release Dynamics

Abstract

This comprehensive study, conducted within the AdriaClim project, offers a detailed exploration of the multifaceted impacts of climate change on the Adriatic Sea. We propose a limited area climate downscaling with mesoscale integrated modeling of the Adriatic water cycle, including the atmosphere, hydrology and marine thermo-hydrodynamics. The analysis covers the climate window between 1992 and 2050, under the high emission scenario RCP8.5 Examination of Sea Surface Temperature (SST) patterns, revealing a discernible warming trend, particularly along the continental slope influenced by the Western Adriatic Coastal Current. This regional warming has substantial implications for the delicate balance of the Adriatic Sea's ecosystems and underscores the need for targeted adaptive measures. Marine Heatwaves (MHWs) exhibit both increased duration and intensity during the projection period. This emphasizes the imminent ecological and socio-economic repercussions, necessitating a proactive approach in policy formulations. The study delves into the intricacies of Brunt–Väisälä frequency analysis, unraveling alterations in ocean circulation and heat transport. This comprehensive understanding of regional climate impacts is crucial for informed decision-making in climate adaptation strategies. Sea Level Rise (SLR) dynamics are explored in detail, showcasing nuanced spatial variations. A latitudinal decrease towards the northeast and heightened levels along the west coast are identified. The mid-term projection indicates a steric-driven increase in SLR, highlighting the importance of region-specific considerations and factors influencing sea level changes. These findings contribute significantly to the broader discourse on global sea-level rise and its regional variations. A pivotal aspect of the study addresses the impact of projected changes in river release on local density stratification and SLR. Projections indicate a mid-term future decrease of approximately 35% in river release, affecting the Northern and Southern sub-basins differently. The Northern sub-basin will experience salinization prevailing on heating through the whole water column due to the projected runoff decrease, resulting in dense water formation increase and moderated sea level rise. Conversely,  the runoff decrease will have a lower impact in the Southern sub-basin where the future changes of other mechanisms may play a major role, making heating prevailing on salinization at intermediate to deep water column, resulting in lower dense water formation and higher SLR. This integrated analysis underscores the intricate dynamics of regional climate impacts on the Adriatic Sea. The interplay of warming trends, altered ocean stratification, intensified MHWs, and river release dynamics demands a holistic approach to climate adaptation. Despite the significant strides made, the study acknowledges certain limitations, such as the absence of land subsidence models. The dynamic nature of the Adriatic Sea and the evolving landscape of climate change necessitate continuous monitoring and refinement of models for heightened accuracy in future projections. The study serves as a testament to the importance of integrated research with a more comprehensive representation of the local water cycle at high time and space resolutions emphasizing the imperative of harmonizing scientific insights with pragmatic policy implementations.