Climate change impacts and vulnerability in Europe 2016

Climate change impacts on society
Projections
The impact of future changes in climate on crop
yield depends on the characteristics of the climatic
change within a region, as well as on a combination
of other environmental, economic, technological and
management factors (Reidsma et al., 2010). A broad
analysis of climate change scenarios for agricultural
productivity in Europe has provided a clear picture
of deterioration of agroclimatic conditions through
increased drought stress and a shortening of the
active growing season across large parts of southern
and central Europe (Trnka, Olesen, et al., 2011). Other
studies suggest an increasing number of unfavourable
years for agricultural production in many European
climatic zones, limiting winter crop expansion and
increasing the risk of cereal yield loss (Peltonen-Sainio
et al., 2011; Rötter et al., 2011; Trnka et al., 2014).
Dynamic crop models may be used to evaluate the
effect of climate change on crop production, provided
that the model is tested for the accuracy of its response
to various climate change factors (Ewert et al., 2015).
Map 5.12 shows projected changes in water‐limited
winter wheat yields in Europe for the 2030s (compared
with the 2000s) for climate projections from two
different climate models (HadGEM2-ES ( 99 ) and
MIROC‐ESM-CHEM ( 100 )) using the WOFOST ( 101 ) crop
model. The top row of the map shows the results
when the CO 2 concentration is assumed to be that of
the 2000s, whereas the bottom row shows the results
when the effect of CO 2 fertilisation (see Box 5.2) on
crop growth was simulated. When no CO 2 fertilisation
effect is taken into account, simulations using both
climate models show a decrease in wheat yields over
most of Europe, with the exception of some northern
areas. When the CO 2 fertilisation effect is taken into
account, model simulations generally show a yield
increase in most areas, with the notable exception
of central Europe for one climate model (HadGEM2).
The simulated moderate yield reduction over central
Europe for this model indicates that increased CO 2 does
not compensate for unfavourable climatic conditions,
such as prolonged and more intense droughts. These
simulations did not include adaptations to climate
change, such as changes in crop species and crop
management, owing to the inherent complexity of
agricultural systems. Therefore, the projected yields
in 2030 may be slightly underestimated. A study on
the potential effectiveness by 2040 of adaptation by
farmers in southern and central Europe suggests that
the adaptation potential to future warming is large for
maize but limited for wheat and barley (Moore and
Lobell, 2014).
Future crop yield developments are subject to
considerable uncertainty, in particular with regard
to climate projections and the magnitude of CO 2
fertilisation effects in practice. For example, Map 5.12
does not consider all of the main sources of
uncertainty, as only two climate models and one crop
model have been used to produce the simulations.
A wider variation would have been found if more
climate model projections and more crop models had
been used. A large proportion of the uncertainty in
climate change impact projections for crop yields are
the result of variations among different crop models
rather than the variations among the downscaled
climate projections (Asseng et al., 2013). Uncertainties
in simulated impacts increase with higher CO 2
concentrations and associated warming.
Map 5.13 provides an aggregated picture of the
expected changes in crop yields across Europe by
considering three crops, an ensemble of 12 GCMs and
the current irrigated area. These estimates include the
effects of changes in temperature, precipitation and
CO 2 concentration on crop yield. The regional pattern of
projected impacts is clear, generally showing improved
conditions in northern Europe and worse conditions in
southern Europe.
Despite the above-mentioned uncertainties, there is a
clear indication of deteriorating agroclimatic conditions
in terms of increased drought stress and a shortening
of the active growing season in central and southern
Europe (Trnka, Olesen, et al., 2011). There is a risk of an
increasing number of extremely unfavourable years,
which might lead to higher interannual variability in
crop yield and constitute a challenge for proper crop
management. Some of the climate-related risk factors,
such as high temperature stress, flooding and adverse
sowing and harvesting conditions, are included only to
a limited extent in current crop models, such as those
used for the projections in Map 5.12. Map 5.14 shows
that the frequency of adverse agroclimatic conditions
for wheat is projected to increase substantially across
Europe under climate change, with the largest risks
generally experienced in southern parts of Europe.
These increases in extreme events may severely restrict
the efficiency of adaptations to climate change, including
the shifting of wheat production to other regions as the
risk of adverse events beyond the key wheat-growing
areas increases even more (Trnka et al., 2014, 2015).
( 99 ) HadGEM-ES: Earth System version of HadGEM2.
( 100 ) MIROC-ESM-CHEM: atmospheric chemistry coupled version of MIROC-ESM ('Model for Interdisciplinary Research on Climate — Earth System
Model').
( 101 ) WOFOST: 'WOrld FOod STudies'.
Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report
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