Page 150 - Climate Change and Food Systems

climate change and food systems: global assessments and implications for food security and trade
systems, (Section 3.2; Carter et al., 1991;
Metzger et al., 2008; Elsgaard et al., 2012). The same projections apply for combined approaches with crop simulation or other crop yield estimation models (e.g. Rötter et al., 1995; Ewert et al., 2005; Hermans et al., 2010). Recently, however, this generally positive picture has been questioned
by some studies that explicitly consider climate scenarios which include anticipated changes
in variability and more frequent (and at times
more severe) extreme events (e.g. Gibbons
and Ramsden, 2008; Trnka et al., 2011, 2014; Semenov and Shewry, 2011; Rötter et al., 2011b, 2013a). Results from such studies suggest considerable challenges for adapting agricultural systems to CC in many parts of Europe.
Working Group II of IPCC concluded in AR4 that agricultural production will be reduced in developing countries primarily if global warming remains below 3o C (Easterling et al., 2007). However, later studies have suggested higher risks. For instance, it has been suggested that
the trends already observed, of increased climatic variability along with more frequent and severe extreme weather events (Field et al., 2012),
will continue or even become stronger under progressive CC. This would lead to faster and more severe yield reductions across the world
than previously anticipated (Lobell et al., 2011). Some of these yield reductions are related to the sensitivity of crops when certain upper temperature thresholds are exceeded (see Section 2.4). In reality, often both severe heat and drought (e.g. during certain times of the day) are responsible for non-linear, negative impacts on yield. Apart from heat and drought, effects of intensive precipitation and flooding on plant physiological processes (e.g. oxygen stress) and soil processes (e.g. nitrate leaching, soil erosion) may significantly reduce
crop yields. All these effects, which are induced
by increased climatic variability, are not adequately captured by most current crop simulation models, although they are usually taken into account by statistical crop yield models. A higher proportion
of statistical modelling in CC impact assessments may be one reason for more pessimistic
projections in recent years; other reasons include gradual improvement of crop simulation models towards more sensitivity with regard to extremes.
3.5 Potential implications for trade and food security
Food price crises in the last years have made it clear that food security cannot be solved solely by more equitable food distribution; accelerating the rate of gains in crop yields and food production capacity is needed simultaneously (Soussana et al., 2012). Currently, at global scale, primary food produced is sufficient and a high percentage of food is wasted, but expected dietary changes and population growth call for substantial increases in food production. Of course, one major cause of hunger and insufficient access to food is poverty, which means that people in low-income countries are particularly vulnerable to CC risks. Generally, questions regarding the impacts of global CC
on agricultural production and the capacity of agriculture to adapt (Howden et al., 2007) and to effectively contribute to mitigation through “climate- smart agriculture” (Smith and Olesen, 2010) have become increasingly important as the window
of opportunity for an effective response to CC is closing.
When comparing CC impacts on crop production from a global perspective to a European perspective, it is clear that Europe will remain relatively well-off under CC in terms of production and yield potential for most food crops. Given the favourable current cultivation conditions in many of the temperate climatic zones of Europe, in conjunction with the high adaptive capacity of European farmers – as compared with the risky production environments of many agricultural regions of the tropics and subtropics (Hillel and Rosenzweig, 2013) – it is expected that the projected future production potential (especially in northwestern Europe) is likely to increase.
Furthermore, given projections regarding Europe’s demographic development and availability of agricultural land reserves (admittedly unequally
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