Page 141 - 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
example, it could be used to evaluate adaptation options for crops under CC – e.g. quantifying how current crops/cultivars will perform in the future, suggesting how breeding efforts should be targeted to better match crop cultivars to future climates,
or recommending how management practices for crops and cropping systems should be changed to improve crop performance under CC.
The potential of crop modelling for supporting breeding efforts or to evaluate various adaptation options has not been at all exploited to date – nor have meaningful combinations of crop simulation modelling with statistical modelling or other techniques (Rötter et al., 2013b).
3. Selected impacts for key crops and regions
In this section, we provide an overview of production trends of the recent past and then move on to describe key impacts of CC on crop production potentials and yields – considering
the main factors influencing land suitability and crop yields. Our focus is on effects of changes in temperature, precipitation and CO2 concentration, and on discrepancies in the impact projections, mainly due to climate model and emission scenario uncertainty. We also examine the influence of technology development, and summarize the shares of the various factors in affecting future crop productivity. Although the primary focus is
on biophysical impacts of CC, we also discuss
the possible implications of the overall results for Europe on global food trade and food security.
3.1 Production trends – past and near future projections
The most widely grown cereals in the European Union (EU-27) are wheat and barley, which in 2011 occupied areas of approximately 26 million hectares and 12 million hectares, respectively (Figure 5a). While the production area for wheat has increased continuously since the 1980s,
cultivation of barley has shown a continuous decrease since the 1980s. The area cultivated with maize has remained more or less stable over the last five decades, fluctuating between 8 and 10 million hectares. A remarkable reduction has been observed in the cultivation area for potatoes, with a decrease from 8 million hectares cultivated in 1961 to 2 million hectares in 2011. A similar trend, though less strong, can also be seen for sugar beet (Figure 5b).
In general, average crop yields in Europe have increased continuously over the last half of the twentieth century. For the last decade or more, however, there have been clear signs with respect to many crops and regions that this trend is not likely to continue and that the linear yield growth rate is slowing down. Figure 5 (c and d) shows
that the increase in barley and wheat yields has weakened since the beginning of the 2000s, while oat yields reached their maximum in the middle of the 1980s and have stagnated or even decreased since then. Yields for maize and sugar beet, however, have continued to grow nearly linearly. In the case of maize, this could partly be explained by its higher temperature optimum for photosynthesis rate (~23 °C) (Bird et al., 1976). Furthermore, the cultivation area of irrigated maize has increased steadily in the main production regions in France, Italy Spain and Greece (Eurostat, 2010), with the effect that the risk of soil-water deficits caused by dry spells has been lowered. The increase in sugar beet yields has been induced primarily by structural changes in the production sector. The Common Market Organization reform of 2006 has led to a further geographical concentration of sugar beet production, with a shift to regions where the soil and climatic conditions are most favourable for growing beets. In fact, more than 85 percent of the total sugar beet production of the EU-27 in 2010 originated in the so-called “beet belt,” including areas in Austria, Belgium, Czech Republic, France, Germany, the Netherlands, Poland and the United Kingdom (Agrosynergie, 2011).
There are also considerable differences in yield levels between European countries, as shown for wheat in Figure 5e. The highest wheat
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