Climate change impacts and vulnerability in Europe 2016

Climate change impacts on society
Map 5.15 Trend in crop water deficit for grain maize during the growing season, 1995–2015
-30°
-20°
-10°
0°
10°
20°
30°
40°
50°
60°
70°
Trend in crop water deficit
for grain maize during the
growing season for the
period 1995–2015 in Europe
m 3 /ha/year
> 50
30 to 50
10 to 30
– 10 to 10
– 30 to – 10
– 50 to – 30
< – 50
60°
50°
50°
No grain maize
simulated
Long term crop water
demand higher than
rainfall
40°
Outside coverage
40°
0 500 1000 1500 km
0°
10°
20°
© European Union 2016 30° Source: Joint Research Centre 40°
Note:
Source:
The linear trend in the crop water deficit is expressed in cubic metres per hectare per year (m 3 /ha/year). The map provides an estimate
of the decrease (blue) or increase (red) of the crop water deficit calculated using the WOFOST model and the JRC's MARS gridded
meteorological data. An increase in the deficit will, in water-limited regions, translate into a corresponding increase in irrigation demand.
Areas where the seasonal crop water demand regularly exceeds the water availability are marked by hatching.
MARS/STAT database.
increase in IWD in most of Europe. For RCP8.5, the
projected increase in IWD exceeds 25 % in most of the
irrigated regions in Europe (Wada et al., 2013). Most
hydrological models in this multi‐model study did not
consider the physiological effect of increased CO 2 ,
which can increase the water-use efficiency of crop
plants. The only available study using a hydrological
and a crop model that considers the physiological effect
of increased CO 2 still estimates that there is a high
likelihood that IWD in southern Europe will increase
by more than 20 % until 2080 (Konzmann et al., 2013).
Regional case studies suggest much higher increases in
IWD in some regions (Savé et al., 2012).
Climate change will also affect water availability. The
Mediterranean area is projected to experience a
decline in water availability, and future irrigation will
be constrained by reduced run-off and groundwater
resources, by demand from other sectors and by
economic costs (Olesen et al., 2011). Assuming that
urban water demands would be prioritised over
agricultural purposes, the proportional reduction of
water availability for irrigation in many European basins
is larger than the reduction in annual run-off (Iglesias
et al., 2013).
The projected changes in the crop water deficit for
grain maize are shown in Map 5.16 for two different
climate models. The simulations are based on the
WOFOST crop model, which considers the effect of
increases in the CO 2 concentrations on the water use
efficiency of maize. The simulations for both climate
model projections for the 2030s show an increasing
crop water deficit for large areas of Europe, in
particular over central Europe. This will increase the
water requirement for irrigation, including in areas not
currently applying irrigation.
Adaptation measures and the integrated management
of water, often at catchment scale, are needed
to address future competing demands for water
between agriculture, energy, conservation and human
settlements. New irrigation infrastructure will be
required in some regions (van der Velde et al., 2010).
238 Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report