Long-run trend in agricultural yield and climatic factors in Europe

Paolo Agnolucci,Vincenzo De Lipsis

doi:10.1007/s10584-019-02622-3

Paolo Agnolucci, Vincenzo De Lipsis

Open Access

https://doi.org/10.1007/s10584-019-02622-3

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Abstract

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.

Highlights

World crop production over the course of the last 50 years has increased at an unprecedented rate as a result of sustained rises in yield (Slafer et al 1994; Rondanini et al 2012; Alston et al 2009), recent contributions point at crop yield slowing down or even stagnatingElectronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Climatic Change (2020) 159:385–405(Bruinsma 2011; Calderini and Slafer 1998; Hafner 2003; Ray et al 2012; Ray et al 2015; Lin and Huybers 2012)
Our contributions to the existing understanding of the longrun trend in crop yield are the following: (1) we show that the evolution of the trend of crop yield should be modelled as a gradually changing stochastic phenomenon, rather than being affected by the sudden permanent breaks currently used in the literature; (2) we find that long-run trends in weather factors are a major determinant of the shape and nature of the yield trend in European crops; and (3) we produce a quantitative measure of the impact of weather factors on the long-run growth rate of crop yield
We begin by highlighting some relevant descriptive features of our data set, which suggest the suitability of our approach

Summary

Introduction

(Bruinsma 2011; Calderini and Slafer 1998; Hafner 2003; Ray et al 2012; Ray et al 2015; Lin and Huybers 2012). Several of these studies focuses on European crops (Brisson et al 2010; Finger 2010; Oury et al 2012; Licker et al 2013), the presence of this phenomenon has been reported on a global scale (Grassini et al 2013). Stagnation in the crop yield may influence future migration flows (Feng et al 2010) and regional political stability and, in the most dramatic cases, trigger violent conflicts (Brinkman and Hendrix 2011). Understanding the historical trend of crop yield is fundamental for the construction of econometric forecasts, but it is important for models simulating future food scenarios (Bruinsma 2011, Tubiello et al 2007). If trends in weather factors have contributed to the historical pattern of the trend of crop yield, they have to be taken into account when computing baseline yield projections from which the weather variability is eventually subtracted (Tollenaar et al 2017)

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