Climate change impacts and vulnerability in Europe 2016

Climate change impacts on environmental systems
Increases in the surface temperature of the North Sea
in recent decades have triggered establishment of
warmwater swimming crabs, which in turn has allowed
establishment of colonies of lesser black-backed
gulls in Belgium and northern France (Luczak et al.,
2012). There is also evidence that the overwintering
distributions of many water birds have changed.
In recent decades, in response to warming, their
distributions have shifted northwards and eastwards
out of the United Kingdom (MCCIP, 2013).
In the eastern Mediterranean Sea, the introduction of
warmwater and tropical alien species from the Red Sea
has been exacerbated by observed warming, leading
to a 150 % increase in the annual mean rate of species
entry after 1998 (Raitsos et al., 2010).
Impacts on fisheries
Climate change is also affecting fish stocks of
commercial interest. Wild fish stocks seem to be
responding to changing temperatures and food supply
by changing their geographical distribution and their
phenology. Mackerel and horse mackerel are spawning
earlier in the English Channel, and both earlier and
further north on the Porcupine Bank (off the west coast
of Ireland). International commercial landings from
the North-east Atlantic Ocean of fish species identified
as 'warm-adapted' (e.g. grey gurnard, red mullet and
hake) have increased by 250 % since the 1980s, while
landings of cold-adapted species (e.g. cod, haddock and
whiting) have halved (MCCIP, 2013). A striking example
for the potentially large economic consequences of the
northwards movement of marine species is the recent
establishment of the Northeast Atlantic mackerel
in Greenlandic waters. This temperature-sensitive
epipelagic fish was first observed in Greenlandic waters
in 2011, following record-high summer temperatures.
Following the rapid development of a large-scale
fishery, mackerel already contributed 23 % to the
export value of all goods from Greenland in 2014
(Jansen et al., 2016).
In the North-east Atlantic Ocean, 72 % of commonly
observed fish species have responded to warming
waters by changing their abundance and/or
distribution (Figure 4.6). Traditionally exploited
fish species have moved further northwards in the
region, while new species have moved in, most likely
as a result of a shift in the thermal regime. While
warming can lead to an increase in fish biodiversity
in a region, there is often a concurrent decrease in
the size structure of the fish population. For example,
in the Greater North Sea, the relatively small species
sprat, anchovy and horse mackerel have increased in
recent decades, whereas the larger species cod and
plaice have decreased at their southern distribution
limit (Perry, 2005). This change may have important
socio‐economic consequences, as the stocks moving
out tend to have a higher value than the stocks
moving in. Pronounced changes in community
structures and species interactions of demersal fish
are projected over the next 50 years, as fish will
experience constraints in the availability of suitable
habitat (Rutterford et al., 2015).
Global projections of changes in total catch of marine
fish and invertebrates in response to ocean warming
suggest a large-scale redistribution of global catch
potential, with an increase in high-latitude regions
and a decline in the tropics. In Europe, a considerable
increase in catch potential is expected in the Arctic
(Cheung et al., 2009; Gattuso et al., 2015).
Projections
As sea surface temperatures increase, marine species
will continue to seek out the most optimal temperature
regime for their metabolic demands, thus leading to
further northwards movement of marine species.
However, quantitative projections are not widely
available. Furthermore, non-indigenous species might
become invasive if conditions favour their metabolic
demands, while native species are weakened (Jones
and Cheung, 2015).
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