In Europe, including the Mediterranean freshwater hotspots, climate change is projected to result in reduced river flow, low oxygen in summer, salinity incursions, further eutrophication and spread of invasive species, compromising the survival of native biodiversity  . The longer growth season in the boreal and Arctic latitudes is projected to aid the invasion of exotic species, and increase lake stratification resulting in lower oxygen below the hypolimnion . In addition, strict cold-water species are projected to lose suitable habitat . An analysis of 1648 species of freshwater fish, amphibians, turtles, plants, molluscs, crayfish and dragonflies, projected ~6% of common and ~77% of rare species to lose 90% of their geographic range  . Even if some species can spread to other areas and follow the climate, Markovic et al.  projected a loss of species, especially molluscs, from the southeastern Mediterranean, including the Balkan biodiversity hotspot  . Similarly, within Europe, Mediterranean fish  and insects  are the most threatened by climate warming, droughts and floods. The fish species of the Danube river delta hotspot  are less susceptible to climate change than in the Balkans  and Anatolian  hotspots. The rest of Europe, from the Iberian Peninsula to Scandinavia is not classified as a biodiversity hotspot. Thus, the areas where freshwater biodiversity is most threatened by climate change in Europe are in two of the three hotspots .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report