The combustion of fossil fuels and the resultant impacts on climate may now represent one of the largest environmental threats. In the Mediterranean Sea, changes in bio-chemical and physical seawater properties resulting from global warming are likely to alter marine biodiversity and productivity, trigger trophic web mismatches and encourage diseases, toxic algal bloom and propagation of thermophilic species. This review highlights the current and potential threats of climate change to the Mediterranean marine ecosystems, including cetaceans, and stresses the emergent necessity for more integrated regulations and policies for the protection of marine biodiversity. For instance, in the Mediterranean Sea, the distribution and abundance of the small euphausid species Meganyctiphanes norvegica is correlated with specific hydrobiological parameters including seawater temperature, salinity and current patterns. Situated at the northern limit of its ecological tolerance, this species, which constitutes the only known food supply of the fin whales (Balaenoptera physalus) in this region, might be affected by climate change-induced alteration of ocean circulation.

Potential impacts of climate change on ecosystems and the environment are generally assessed by summarizing climate change scenarios for broad regions (for example countries), or by specific modelling exercises. This paper presents an alternative approach for summarizing climate change impacts on the European environment, by linking climate change scenarios to recognized environmental divisions. Sixteen climate scenarios from four general circulation models were therefore linked to 84 statistically derived strata sharing common environmental features. In this way, the future distribution of the strata, as defined by their climate characteristics, were quantified and mapped. The results show that Europe is likely to experience major environmental shifts, with pronounced regional variations. As expected, environmental strata shift northwards. In particular the southern Mediterranean strata are projected to expand, whereas Atlantic environments remain much more stable. Alpine and Mediterranean mountain environments decline dramatically. However, the Scandinavian zones show no consistent pattern of change. More detailed analysis of four sample regions shows that the impacts of the projected shifts will largely depend on regional characteristics. Environmental conservation, regional assessments and scenario development could therefore be facilitated by combining relevant regional datasets (for example for vegetation, land cover and species distribution) with the shifting environmental strata.