Unprecedented warming and salinization observed in the deep Adriatic

Abstract

The deep Southern Adriatic is a Mediterranean region highly sensitive to climate change, influenced by dense water cascading from the northern Adriatic and heat/salt transport from the Eastern Mediterranean. Historical (since 1957) and modern (permanent and opportunistic temperature and salinity sampling, Argo floats, fixed moorings) measurements reveal a substantial change since the mid‐2000s in thermohaline properties. Historically marked by steady increases in temperature, salinity, and density, with substantial saw‐tooth decadal variability, the near‐bottom Southern Adriatic has experienced unprecedented warming (0.8°C) and salinization (0.2) over the past decade, accelerating in time and reversing density trends. The inflow of much more saline waters reduced stratification and altered dense water properties at its source in the northern Adriatic. This at least fivefold acceleration of the high‐emission regional climate projections may have substantial effects on the Adriatic biogeochemistry and living organisms, changing sea level trends and more.