Storylines of weather-induced crop failure events under climate change

Henrique M D Goulart,Juraj Balkovic,Bart Van Den Hurk,Christian Folberth,Karin Van Der Wiel

doi:10.5194/esd-12-1503-2021

Abstract

Abstract. Unfavourable weather is a common cause for crop failures all over the world. Whilst extreme weather conditions may cause extreme impacts, crop failure commonly is induced by the occurrence of multiple and combined anomalous meteorological drivers. For these cases, the explanation of conditions leading to crop failure is complex, as the links connecting weather and crop yield can be multiple and non-linear. Furthermore, climate change is likely to perturb the meteorological conditions, possibly altering the occurrences of crop failures or leading to unprecedented drivers of extreme impacts. The goal of this study is to identify important meteorological drivers that cause crop failures and to explore changes in crop failures due to global warming. For that, we focus on a historical failure event, the extreme low soybean production during the 2012 season in the midwestern US. We first train a random forest model to identify the most relevant meteorological drivers of historical crop failures and to predict crop failure probabilities. Second, we explore the influence of global warming on crop failures and on the structure of compound drivers. We use large ensembles from the EC-Earth global climate model, corresponding to present-day, pre-industrial +2 and 3 ∘C warming, respectively, to isolate the global warming component. Finally, we explore the meteorological conditions inductive for the 2012 crop failure and construct analogues of these failure conditions in future climate settings. We find that crop failures in the midwestern US are linked to low precipitation levels, and high temperature and diurnal temperature range (DTR) levels during July and August. Results suggest soybean failures are likely to increase with climate change. With more frequent warm years due to global warming, the joint hot–dry conditions leading to crop failures become mostly dependent on precipitation levels, reducing the importance of the relative compound contribution. While event analogues of the 2012 season are rare and not expected to increase, impact analogues show a significant increase in occurrence frequency under global warming, but for different combinations of the meteorological drivers than experienced in 2012. This has implications for assessment of the drivers of extreme impact events.

Highlights

Soybeans are important for modern global society
The work is divided into three parts (Fig. 1): first, we develop a statistical model that links soybean failures generated by a crop model to local meteorological conditions
This work presents an evaluation of the impacts of global warming on weather-induced soybean failure events

Summary

Introduction

Soybeans are important for modern global society. They are used for human consumption, the main source of protein for animal feed worldwide and the second most consumed type of vegetable oil (Hartman et al, 2011). The difference in scale between local production and global consumption makes soybeans the most traded crop in value in the world (FAO, 2021). Such a broad and extensive trade network renders the soybean supply chain especially vulnerable to local perturbations at the growing regions. Local shocks on production sites can potentially have worldwide consequences, as evidenced by the 2012 season, when exceptional low yields in most of the midwestern United States drove global soybean prices to the highest values ever recorded (Zhang et al, 2018)

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Conclusion