Mediterranean Sea and Region, including Adriatic Sea

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Mediterranean Sea and Region

Considering vulnerable European regions, the Mediterranean Sea is a largely enclosed sea, with high temperature and salinity, and decreasing fresh water due to dams and river diversions. Under the changing climate regime, sea surface temperatures and salinity will increase. Biodiversity, conservation, water quality, quantity and seasonal flows will be significantly affected. The negative impacts of pollution and nutrient into waters may increase. Depending on the local characteristics, erosion, sediment deposition, drought, desertification and flooding may intensify or shift.

Coastal and beach tourism is also an important source of income in the Mediterranean and south Atlantic regions. The ongoing economic viability of many regions and local communities may depend on an acceptable balance being tourist development and the maintenance of the coastal and marine ecosystems that tourism activity depends upon.

Complex interactions between overfishing and climate change could facilitate ecosystem shifts. A recent example may be presence of algal blooms and jellyfish in Mediterranean and other regions due to combination of higher water temperatures, overfishing and nutrient influxes. In the Mediterranean, algal blooms are boosted by nitrate and phosphate influxes from farming and human wastes. Jellyfish also benefit from the reduction in the number of natural predators like loggerhead turtles and the bluefin tuna, which have been drastically reduced by over-fishing.

Once jellyfish are predominant, it can difficult for juvenile fish populations to re-establish that predator-prey relationship. Reduced river flows during hotter summers might also lead to increased numbers of jellyfish near the shore, as freshwater currents no longer keep the jellyfish offshore. The predominance of jellyfish and algal blooms in coastal waters and adjacent to beaches also reduces the attractiveness of tourism for those beaches.

Enclosed shallow seas such as the Mediterranean Sea, Baltic Sea and Black Sea are very vulnerable to warming and other climate changes. On a longer term basis, ecosystems shifts such as jellyfish and algal could be perceived as an indication that the Mediterranean Sea and region is under stress, and that the sea is becoming "tropicalised". The Mediterranean climate, typified by cool wet winters and dry hot summers, may be shifting with related impacts on terrestrial, coastal and marine ecosystems and biodiversity, and the economies and communities they support.

In complex ways, climate change can affect the ecological or carrying capacity of these natural ecosystems, which forms the overall basis for tourist, business and local developments in the Mediterranean and south Atlantic region. In order to allow these coastal and marine ecosystems to adapt to the climate changes that will occur, human stresses, including those caused by all these developments, need to be reduced. Among other matters, this requires an integrative and ongoing ecosystem based approach to the planning of these developments. Separate from these economic and conservation needs, coastal and marine ecosystems meet many needs for local communities such as food, transport, recreation, as well as providing cultural and historical links.