Climate change impacts and vulnerability in Europe 2016

Climate change impacts on society
climate projection model anticipates a 3.8 % overall
habitat expansion for Ixodes ricinus in Europe by
2040–2060, with expansion into higher altitudes and
latitudes (notably Scandinavia and the Baltic countries)
and a contraction in some areas including the Alps,
the Pyrenees, the interior of Italy and north-western
Poland (Boeckmann and Joyner, 2014). This aligns
with other models of climate change that anticipate
Ixodes ricinus range expansions under climate change
scenarios (Estrada-Peña, Ayllón, et al., 2012; Porretta
et al., 2013), but it has been acknowledged that
many uncertainties exist in these models and that
extrapolating the projected habitat range of ticks to
generate projections of the incidence of tick-borne
disease leads to additional uncertainties.
Nonetheless, the incidence of TBE may shift to higher
altitudes and latitudes along with the distribution of
Ixodes ricinus, potentially increasing the risk in some
parts of northern and central Europe, unless targeted
vaccination programmes and TBE surveillance are
introduced. Similarly, TBE risk is generally expected
to decrease in southern Europe. Warmer winters
may facilitate the expansion of Lyme disease to
higher latitudes and altitudes, particularly in northern
Europe, but it would decrease in the parts of Europe
that are projected to experience increased droughts
(Semenza and Menne, 2009).
Projections: mosquito-borne diseases
Various studies have found that warm seasonal and
annual temperature and sufficient rainfall provide
favourable climatic conditions for Aedes albopictus
in Europe (Roiz et al., 2011). The climatic suitability
for Aedes albopictus is projected to increase where
climate models project warmer and wetter climates,
such as south-eastern United Kingdom (Medlock
and Leach, 2015), the Balkans and central Europe,
while suitability generally decreases where climate
becomes drier, such as in some regions of Spain and
Portugal (Caminade et al., 2012). This corresponds
with a modelling study that demonstrated a general
decline in habitat suitability in southern Europe and
the Mediterranean area, and an increase in habitat
suitability in northern and eastern European countries
(Proestos et al., 2015).
The risk of chikungunya may increase in Europe,
particularly in those regions where the seasonal
activity of Aedes albopictus aligns with the seasonality
of endemic chikungunya infections abroad, thereby
potentially increasing the risk of importation via
travellers (Charrel et al., 2008). Models of chikungunya
transmission in Europe under climate change
scenarios have identified France, northern Italy and
the Pannonian Basin (east-central Europe) as the
areas at highest risk, with increases in the level of risk
in much of western Europe, including the Benelux
countries and Germany. In contrast, Mediterranean
regions demonstrated a decreased risk, although
the models suggested that they will mostly remain
climatically suitable for chikungunya transmission
(Map 5.6) (Fischer et al., 2013).
A climate-related increase in the density or active
season of Aedes albopictus could lead to a small
increase in the risk of dengue in Europe. The risk could
also increase if the temperature increase facilitated
the re-establishment of Aedes aegypti, the primary
dengue vector. Further modelling studies are required
to assess whether climate change would increase or
decrease the climatic suitability for Aedes aegypti in
continental Europe.
Some malaria models suggest that there will be
increased suitability for malaria transmission in
continental Europe under future climate change,
but projected malaria impacts are highly sensitive to
model design (Caminade et al., 2014). Nevertheless,
socio-economic development, land-use and public
health control measures would most likely be
sufficient to mitigate the risk of malaria at the fringes
of its distribution, despite the likelihood of sporadic
introductions of the parasite through global travel
(Semenza et al., 2014).
Climate change has previously not been expected
to have a significant impact on WNV transmission
in Europe (Gale et al., 2009; Gould and Higgs,
2009). However, climate change could influence the
transmission of the virus by affecting the geographical
distribution of vectors and pathogens, by changing the
migratory patterns of bird populations and through
changes in the life cycle of bird-associated pathogens.
Temperature increases could also play a role. The
WNV risk in Europe has been projected into 2025
and 2050, with July temperature projections under a
medium emissions scenario (SRES A1B), keeping other
variables constant (e.g. state of vegetation, water
bodies and bird migratory routes) (Semenza et al.,
2016). The results reveal a progressive expansion of
areas with an elevated probability for WNV infections,
particularly at the edges of the transmission areas
(Map 5.7). Projections for 2025 show an increased
probability of WNV infection in eastern Croatia,
north‐eastern Greece and north-western Turkey;
high‐risk areas will have expanded even more by 2050.
216 Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report