Shifts in comparative advantages for maize, oat and wheat cropping under climate change in Europe

Climate change is anticipated to affect European agriculture, including the risk of emerging or re-emerging feed and food hazards. Indirectly, climate change may influence such hazards (e.g. the occurrence of mycotoxins) due to geographic shifts in the distribution of major cereal cropping systems and the consequences this may have for crop rotations. This paper analyses the impact of climate on cropping shares of maize, oat and wheat on a 50-km square grid across Europe (45–65°N) and provides model-based estimates of the changes in cropping shares in response to changes in temperature and precipitation as projected for the time period around 2040 by two regional climate models (RCM) with a moderate and a strong climate change signal, respectively. The projected cropping shares are based on the output from the two RCMs and on algorithms derived for the relation between meteorological data and observed cropping shares of maize, oat and wheat. The observed cropping shares show a south-to-north gradient, where maize had its maximum at 45–55°N, oat had its maximum at 55–65°N, and wheat was more evenly distributed along the latitudes in Europe. Under the projected climate changes, there was a general increase in maize cropping shares, whereas for oat no areas showed distinct increases. For wheat, the projected changes indicated a tendency towards higher cropping shares in the northern parts and lower cropping shares in the southern parts of the study area. The present modelling approach represents a simplification of factors determining the distribution of cereal crops, and also some uncertainties in the data basis were apparent. A promising way of future model improvement could be through a systematic analysis and inclusion of other variables, such as key soil properties and socio-economic conditions, influencing the comparative advantages of specific crops.

气候变化预计将对欧洲农业造成影响，其中涵盖新发或再现的饲料与食品危害风险。间接而言，气候变化可能通过主要谷类种植系统分布的地理迁移，以及由此对作物轮作制度带来的连锁效应，影响此类危害（例如真菌毒素（mycotoxins）的发生）。本研究分析了欧洲（北纬45°至65°）范围内50公里格网中玉米、燕麦与小麦的种植占比受气候的影响情况，并基于两种分别代表中等强度和强气候变化信号的区域气候模型（RCM）对2040年前后的气候预测结果，通过模型估算了种植占比随气温与降水变化的响应情况。上述预测的种植占比基于两种RCM的输出结果，以及针对气象数据与观测得到的玉米、燕麦、小麦种植占比之间关系推导得到的算法。观测得到的种植占比呈现出从南到北的纬度梯度特征：玉米种植占比在北纬45°至55°区间达到峰值，燕麦在北纬55°至65°区间达到峰值，而小麦的种植占比则在欧洲各纬度带分布相对均匀。在预测的气候变化情景下，玉米的种植占比整体呈现上升趋势，而燕麦的种植占比未出现显著增长的区域。对于小麦而言，预测结果显示其种植占比在研究区域的北部存在上升趋势，南部则呈现下降趋势。本研究所采用的建模方法简化了决定谷类作物分布的各类影响因素，同时数据基础中也存在一定的不确定性。未来改进模型的可行路径之一，是通过系统分析并纳入其他影响特定作物比较优势的变量，例如关键土壤属性与社会经济条件等。