Climate change scenarios (Hulme et al., 2002) indicate
annual average temperature increases of 2 and 3.5°C by the 2080s;
wetter winters (winter daily precipitation up to 20% heavier), and
drier summers with the largest relative changes in the south and
east where summer precipitation may decline by up to 50%. Sea
levels are also expected to rise around the UK - between 26 and 86
cm by 2080s.
Although pollution monitoring is currently inadequate for
identifying climate change related impacts there are many potential
impacts that climate change could have on the UK marine
environment. Changes to rainfall patterns may result in changes to
the movement and distribution of chemicals e.g. increased leaching
of pesticides applied to agricultural land during certain periods
of the year. Increased storm events during the winter will
increase storm water flows in rivers and potentially inputs of
untreated sewage effluent. Decreased river flows in the
summer particularly in the South of England will result in higher
relative contributions of treated sewage effluent. The
biological oxygen demand will increase because of the increase in
organic matter from treated sewage as well as any rise in
temperature, which will increase bacterial respiration. Heavy
storm events during summer periods are likely to result in flushing
of untreated sewage effluent and diffuse pollutants from surface
runoff in storm overflows. The release of
sediment-associated contaminants present on the seabed may also be
changed by increases in temperature, changes in salinity regimes
and increased storm events.
Increased risk of flooding because of climate change has
implications for the inundation of land that is contaminated.
There may therefore be a greater risk of contaminants being
remobilised in floodwater and of contaminated
sediment and water reaching the freshwater and marine
environment. The location of coastal industries e.g. power
generation will need to take account of the increased risk of
flooding in some coastal areas. With the increased development of
ports and coastal areas handling of historically contaminated
sediments is also an issue of increasing concern and its
redistribution in the environment will be influenced by storm
events.
The use and fate in the marine environment of specific chemicals
may also be influenced by climate change because of changes in
farming practice (e.g. increased use of some pesticides) and
consumer choice (e.g. increased use of UV sunscreens and fate and
effects in the aquatic environment (Buser et al., 2006))
