Agriculture is exposed to weather variation, with implications for food security, land allocation, trade and economic activity. Understanding the impact of changes in temperature and precipitation on crop yields is a vital step in developing policy and management options to feed the world over the coming century. As the current literature has focused on a few staple crops, we implement global statistical models to examine the influence of weather and management practices on yields of 18 crops, accounting for 70% of crop production by area and 65% of calorific intake. We focus on the impact of temperature and find considerable heterogeneity in the responses of yields across crops and countries, by identifying winners and losers from warming trends. Irrigation is found to alleviate negative implications from temperature increases. Countries where increasing temperature cause the most negative impacts are typically those which are the most food insecure, having the lowest calorific food supply and the lowest crop yield. Our results suggest that, in these countries, it will be important to co-ordinate international actions to raise yields through improvement and modernization of agricultural practices to counteract future adverse impacts of climate change.

Reliable projections of crop production are an essential tool for the design of feasible policy plans to tackle food security and land allocation, and an accurate characterization of the long-run trend in crop yield is the key ingredient in such projections. We provide several contributions adding to our current understanding of the impact of climatic factors on crop yield. First of all, reflecting the complexity of agricultural systems and the time required for any change to diffuse, we show that crop yield in Europe has historically been characterized by a stochastic trend rather than the deterministic specifications normally used in the literature. Secondly, we found that, contrary to previous studies, the trend in crop yield has slowly changed across time rather than being affected by a single abrupt permanent change. Thirdly, we provide strong evidence that climatic factors have played a major role in shaping the long-run trajectory of crop yield over the decades, by influencing both the size and the statistical nature of the trend. In other words, climatic factors are important not only for the year-to-year fluctuations in crop yield but also for its path in the long-run. Finally, we find that, for most countries in this study, the trend in temperature is responsible for a reduction in the long-run growth rate of yield in wheat, whereas a small gain is produced in maize, except for Southern European countries.

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