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The Fourth Assessment Report of the Intergovernmental Panel
on Climate Change states that warming of the climate system is
unequivocal, as is now evident from observations of increases in
global average air and ocean temperatures, widespread melting of
snow and ice, and rising global average sea level. Natural systems,
including oceans and coasts, are being affected by regional climate
changes, particularly by temperature increases. Besides rising sur-
face water temperatures and sea level, impacts are or will be as-
sociated with changes in the wave climate, circulation, ice cover,
fresh water run-off, salinity, oxygen levels and water acidity.
Shifts in ranges and changes in algal, plankton and fish abun-
dance have already been observed in high-latitude oceans.
Besides these there are other effects that, based on published
literature, have not yet become established trends as they are
difficult to discern due to adaptation and non-climatic driv-
ers. Sea level-rise is negatively contributing to coastal erosion,
losses of coastal wetland ecosystems, including salt marshes
and mangroves, and increasing damage from coastal flooding
in many areas. These effects will be exacerbated by increasing
human-induced pressures on coastal areas.
CLIMATE CHANGE IN THE SEA