Moore Frances C, Lobell David B
Emmett Interdisciplinary Program in Environment and Resources, Center for Food Security and the Environment, and
Center for Food Security and the Environment, and Department of Environmental Earth System Science, Stanford University, Stanford, CA 94305.
Proc Natl Acad Sci U S A. 2015 Mar 3;112(9):2670-5. doi: 10.1073/pnas.1409606112. Epub 2015 Feb 17.
Europe has experienced a stagnation of some crop yields since the early 1990s as well as statistically significant warming during the growing season. Although it has been argued that these two are causally connected, no previous studies have formally attributed long-term yield trends to a changing climate. Here, we present two statistical tests based on the distinctive spatial pattern of climate change impacts and adaptation, and explore their power under a range of parameter values. We show that statistical power for the identification of climate change impacts is high in many settings, but that power for identifying adaptation is almost always low. Applying these tests to European agriculture, we find evidence that long-term temperature and precipitation trends since 1989 have reduced continent-wide wheat and barley yields by 2.5% and 3.8%, respectively, and have slightly increased maize and sugar beet yields. These averages disguise large heterogeneity across the continent, with regions around the Mediterranean experiencing significant adverse impacts on most crops. This result means that climate trends can account for ∼ 10% of the stagnation in European wheat and barley yields, with likely explanations for the remainder including changes in agriculture and environmental policies.
自20世纪90年代初以来，欧洲一些农作物产量出现停滞，同时生长季节出现了具有统计学意义的变暖。尽管有人认为这两者存在因果联系，但此前没有研究正式将长期产量趋势归因于气候变化。在此，我们基于气候变化影响和适应的独特空间模式提出了两种统计检验方法，并在一系列参数值下探究它们的效能。我们表明，在许多情况下，识别气候变化影响的统计效能较高，但识别适应的效能几乎总是很低。将这些检验应用于欧洲农业，我们发现有证据表明，自1989年以来的长期气温和降水趋势分别使整个欧洲大陆的小麦和大麦产量降低了2.5%和3.8%，并使玉米和甜菜产量略有增加。这些平均值掩盖了整个大陆的巨大异质性，地中海周边地区的大多数作物受到了重大不利影响。这一结果意味着气候趋势可以解释欧洲小麦和大麦产量停滞的约10%，其余部分的可能原因包括农业和环境政策的变化。
