Climate Change and the European Water Dimension - Agri ...

Sea level rise is partially due to expansion of seawater volume with increasing
temperature. The Mediterranean Sea being almost totally landlocked, and with
restricted exchange of water with the Atlantic ocean has often been compared to a
miniature model of the worlds oceans, where environmental changes occurring at
large scale can be effectively measured and monitored. In terms of climatic warming
the Mediterranean Sea is probably one of the first places where such effect has been
measured.
Change in surface temperature (SST) conditions has been analyzed using NOAA
AVHRR satellite data covering the Mediterranean Sea for the period January 1982 to
December 2000 (L. Nykjaer, JRC, pers. comm.). Figure IV.C.3 shows the trend of
SST from best linear fit through the dataset. An increasing SST trend is evident over
the entire basin with the eastern Mediterranean Sea showing an increase of 0.12
°C.year -1 , and about 0.1 °C.year -1 for the western basin. The spatial resolution of the
satellite data (4 km) additionally reveals non-homogeneous patterns of the SST trend
especially in the eastern basin. These patterns are linked to mesoscale circulation
and changes in water mass distribution. Temperature increases may exceed 3-4°C at
mesoscale resolution over the 19-year period, with consequences to sea level rise,
ecosystem functioning, eutrophication, physical circulation, biodiversity and marine
resource distribution.
Figure IV.C.3. Annual rate of SST change for the Mediterranean Sea for the
period 1982-2000. (from L. Nykjaer, JRC Ispra, personal communication).
In addition to an increase in the volume of water, the impacts of a sea level rise
include coastal flooding and erosion, as well as landward intrusion of salt water with
subsequent changes in the chemical characteristics of near-shore aquifers and
coastal lakes, subsequently affecting the ecosystem community structures. Coastal
wetlands are likely to be most vulnerable to the effects of sea level rise (Figure
IV.C.4). All these effects will be further exacerbated by an increasing vulnerability to
storms and waves.
However, the impact of sea level rise onto these habitats can be to some extent
mitigated by changes in hydrologic cycle and intensification of precipitation on land
leading to larger sediment delivery from the catchment basin, and subsequent
accretion in low-lying areas and deltaic environment. A complete assessment of sea
level effects on the coastal systems must therefore take into account changes in the
hydrologic cycle over land.
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