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

topics in coastal lagoons (de Wit et al., 2001, Cadée et al., 2001, Herman et al.,
2001). Due to these characteristics, and specially due to the fact that lagoon
ecosystems are fragile because they receive water draining directly from highly
inhabited areas, and because of their shallow water and low water volume compared
to the adjacent sea, there is a high probability that, among Mediterranean marine
ecosystem, Mediterranean coastal lagoons will be the first to react to consequences
of changes in climatic trends. Trends may include temperature elevation,
precipitation distribution patterns, weather extremes, sea level raise (SLR) and UVB
radiation (UVBR: 280-320 nm,) increase. However, it may be difficult to distinguish
between these and already existing anthropogenic and climate change effects.
Assessments are further hampered by lack of historical time series, the Venice
lagoon being probably the only Mediterranean lagoon where this analysis has been
attempted (Camuffo and Sturaro, 2004, Day et al., 1999).
IV.D.2 Major Drivers of Change in Mediterranean Coastal Lagoons
The main changes of climatic conditions in Europe and in the Mediterranean area
specifically have been summarised in the IPCC (Intergovernmental Panel on Climate
Change) reports (IPCC, 2001).
Temperature
The report foresees an annual temperature increase at a rate of between 0.2 and
0.6°C per decade over the Mediterranean arc with an increase in the frequency of
hot summers and a decrease in the cold winters (1/10 in 1961-1990).
Precipitation
The general pattern for southern Europe in annual precipitation is a small decrease
(maximum –1% per decade) with a marked contrast between winter and summer
patterns of precipitation change. The Mediterranean area will become wetter in the
winter season (between +1 and +4% per decade) and drier in summer (drying of as
much as –5% per decade).
Weather extremes
Climate change scenarios do not explicitly quantify changes in daily weather
extremes. However, it is very likely that frequencies and intensities of summer heat
waves will increase throughout Southern Europe; and that intense precipitation
events will increase in frequency, especially in winter, and that summer drought risk
will increase in southern Europe; it is also possible that gale frequencies will
increase.
UVB radiation
The accumulation of CFCs and other chlorinated and brominated compounds has
depleted the stratospheric ozone layer with consequent increases in ultraviolet-B
radiation (UVBR: 280-320 nm) at the Earth’s surface.
Sea level
Estimates of Global-mean sea level rises by the 2050s are around 13–68 cm. These
estimates make no allowance for natural vertical land movements. Owing to tectonic
adjustments following the last glaciation, and the different pattern of average
atmospheric pressure change, there are likely to be regional differences across
Europe in the natural rates of relative sea-level change.
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