Climate change impacts and vulnerability in Europe 2016

Climate change impacts on environmental systems
decade (Urli et al., 2014). Nevertheless, not all studies
found clear climate signals, partly because tree species
can experience time lags in their migration response to
climate change (Rabasa et al., 2013; Renwick and Rocca,
2015).
In addition to range shifts, changes in forest composition
have been observed in the past. In a Swedish
spruce‐beech forest, a long-term study covering the
period since 1894 showed that spruce has been losing
its competitive advantage over beech since 1960 (Bolte
et al., 2010). In north-east Spain, beech forests and
heather heathlands have been replaced by holm oak
forest at medium altitudes (800–1 400 m), mainly as
a result of the combination of warming temperatures
and land‐use change (Penuelas and Boada, 2003).
Field‐based observations from a forest inventory
providing presence and absence information from 1880
to 2010 for a Mediterranean holm oak species (Quercus
ilex) have been used to investigate the migration speed
in the past. In four studied forests in France along the
Atlantic coast, Quercus ilex has colonised a substantial
amount of new space, but the northwards movement
occurred at an unexpected low maximum rate of 22 to
57 m/year across the four forests (Delzon et al., 2013).
Extreme climate and weather events such as droughts
can have negative effects on food webs and regional
tree dieback For the Iberian Peninsula, the defoliation
of trees due to a water deficit rose significantly
between 1987 and 2007 in all 16 examined tree species.
Defoliation doubled on average, and this trend was
paralleled by significant increases in tree mortality
rates in drier areas (Carnicer et al., 2011). Furthermore,
droughts can lead to secondary impacts on forests
through pests and pathogens (Jactel et al., 2012).
Projections
Climate change is expected to strongly affect the
biological and economic viability of different tree species
in Europe, as well as competition between tree species.
A study in Finland showed that climate change may lead
to a local reduction of forest growth but total forest
growth nationwide may increase by 44 % during the
21st century (Kellomäki et al., 2008). Observations and
simulations of tree mitigation rates suggest that only
fast-growing, early successional tree species will be able
to track climate change (Delzon et al., 2013; Fitzgerald
and Lindner, 2013). Recent studies that simulated
forest composition and range shifts in Europe and at
the global level using different climate and land-use
scenarios suggest upwards shifts in the tree line and
northwards migration of boreal forests (Lindner et al.,
2014; Betts et al., 2015). Broadleaf tree cover in Europe
is projected to increase during the 21st century under
all climate scenarios, whereas needleleaf tree cover
decreases, despite a northward extension in northern
Europe (Map 4.17).
A large-scale integrated project on adaptive forest
management (MOTIVE) ( 66 ) applied an array of models
(empirical as well as hybrid and process-based) in
the analysis of the impacts of climate change on
38 European tree species. The results show that more
drought-tolerant species such as sessile oak (Quercus
petraea), pubescent oak (Quercus pubescens) and Scots
pine (Pinus sylvestris) can be expected to become more
abundant at lower altitudes throughout Europe, while
other species such as beech (Fagus sylvatica), sycamore
maple (Acer pseudoplatanus), lime (Tilia), elm (Ulmus) or
silver fir (Abies alba) are likely to see further reductions in
their ranges. Species from (sub-)Mediterranean regions
such as holm oak (Quercus ilex), hop hornbeam (Ostrya
carpinifolia) and cork oak (Quercus suber) are expected
to extend their ranges to the north. Different pine
species are also expected to extend their ranges quite
considerably. Some species, such as Scots pine (Pinus
sylvestris), might face indirect threats from insects and
other pest outbreaks, rather than direct threats from
climate change alone. In summary, the projected range
shifts will affect the forest structure quite considerably.
Such changes will also affect the functioning of forest
ecosystems and the services these ecosystems could
provide (Fitzgerald and Lindner, 2013).
Another modelling study assessed the impacts of
projected climate change on forest composition across
Europe and the economic consequences in terms of
annual productivity and land value (Hanewinkel et al.,
2012). It projected that the major commercial tree
species in Europe, Norway spruce, will shifts northwards
and to higher altitudes. It will lose large parts of its
present range in central, eastern and western Europe
under all scenarios (SRES A1B, A1FI and B2). Depending
on the emissions scenario and climate model, between
21 and 60 % (mean: 34 %) of European forest lands
were projected to be suitable only for a forest type of
Mediterranean oak, with low economic returns by 2100,
compared with 11 % in the baseline period 1961–1990.
As a result of the decline of economically valuable
species, the value of forest land in Europe is projected
to decrease between 14 and 50 % (mean: 28 % for an
interest rate of 2 %) by 2100. The economic loss in land
estimation value is estimated at several hundred billion
euros.
( 66 ) MOTIVE: 'Models for Adaptive Forest Management'; see http://motive-project.net.
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