Page 149 - Climate Change and Food Systems

chapter 4: an overview of climate change impact on crop production and its variability in europe, related uncertainties and research challenges
table 1
Relative yield changes derived from regional impact studies for selected crops and countries representing northern (Denmark), western (United Kingdom), central (Austria), eastern (Bulgaria) and southern (Italy) Europe, taking the effects of climate change and elevated CO2 concentration into consideration
Country
Projected time horizon
Wheat
Barley
Maize
Source
Reference yield Reference yield change yield (t/ha) (%) (t/ha)
yield change (%)
-35 - 24
-3 - 10
-10
n.a.
-33 - 11
Reference yield (t/ha)
n.a.
n.a.
10.9
7 3
9.2 3
yield change (%)
n.a. (a)
n.a. (b)
-4 (c)
-21 - 6 (d)
-24 - -9 (e)
Denmark
UK
Austria
Bulgaria
Italy
2051 - 2070
2041 - 2070
2007 - 2038
2040 - 2069
End of the century
5.8 9 - 19
9.7 17 - 29
6.3 -5
6 14 - 45
5.2 -15 - 0
4.1 1
5.9 1
4.9 1
n.a.
4.6 2
1) spring barley, 2) winter barley, 3) irrigated, n.a. not available
(a) Doltra et al. (2012), (b) Gibbons & Ramsden (2008), (c) Strauss et al. (2012), (d) Alexandrov & Hoogenbaum (2000), (e) Tubiello et al. (2000)
northern Europe (Denmark) and western Europe (United Kingdom), with increases of between 9
to 19 percent and 17 to 29 percent, respectively. In addition, the remarkable increase in projected yields for locations in Bulgaria (up to 45%) corresponds with the results of studies conducted at coarser scale (see Figure 8b, 9a-c); so does the decrease reported for an area in northern Italy.
Regional projections for barley and maize are predominantly negative across Europe. Barley yields are likely to decrease in Austria, Denmark and Italy, although the upper (positive) end of the yield range in Italy was simulated for late-maturing cultivars. Such cultivars can counterbalance
the risk of potential crop yield reduction caused by accelerated phenological development in
a warmer climate (Tubiello et al., 2000) if they are not exposed to increased drought risk.
The projected decreases in maize yields were primarily caused by a shorter growing period, due to accelerated phenological development under increased air temperatures (Alexandrov and Hoogenbaum, 2000; Tubiello et al., 2000). It should be borne in mind that the projected yields for Italy and Bulgaria correspond to irrigated
maize and thus are not directly comparable with the rainfed maize projections presented in Figure 9d-f.
3.4 Projections of future crop production potential (yields and suitability)
Based on the results from assessing shifts in biophysical land suitability for the cultivation of arable crops and grassland, in combination with crop yield simulations and other crop yield models, we can conclude that, for Europe as a whole, future crop production potential would increase under CC. Positive changes prevail for northern and central Europe, but there are some risks for reduced production potential in the Mediterranean. There is considerable agreement that climatic suitability will improve for crop cultivation under CC in many parts of Europe, regardless of the assessment method. Overall, improved cultivation conditions are projected based on simple agroclimatic indices and phenology models, or
by using more complex biophysical classification
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