Climate change threatens global breadbaskets

Extreme climatic conditions are responsible for at least 30% of the annual fluctuations in worldwide agricultural yield. An innovative IIASA modelling study showed that extreme temperatures could lead to unusually low harvests if more than one of the world’s breadbaskets are affected at the same time.

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Climate change is not just resulting in a steady increase in temperatures, but also in an increased frequency and severity of extreme climatic events like droughts, heat waves, and floods, which are particularly damaging to agriculture. Climatic shocks to agricultural production can contribute to food price spikes and famine with the potential to trigger other systemic risks, including political unrest and migration. Under normal conditions, the global food system can compensate for local crop losses through grain storage and trade, but it is doubtful whether the current system is resilient to more extreme conditions.

The possibility of climatic extremes hitting more than one global breadbasket – the regions responsible for growing much of the world’s food crops – has been a growing cause for concern among researchers and policymakers. However, only a few studies have quantitatively investigated the probability of simultaneous production shocks. In the first modeling study of its type and scale, IIASA researchers dynamically explored the risk of simultaneous crop failures by explicitly accounting for spatial dependence between the breadbasket regions.

The researchers looked at climatic and crop yield data for the main agricultural regions within the highest crop producing countries from 1967 to 2012 and found that there has been a significant increase in the probability of multiple global breadbasket failures particularly for wheat, maize, and soybeans: annual probability would increase from 2.3% under historical conditions to 4.7% and 6.6% in scenarios of 1.5°C respectively 2°C global warming. At a global scale, the analysis shows both negative and positive correlations between the world’s breadbaskets and climatic dependence.

Heavy rainfall in India will, for example, negatively affect the local soybean harvest, but this can be mitigated by imports from Argentina, thus balancing out crop losses. On the other hand, the risk of increasing temperatures in Australia could affect the amount of wheat they are able to export to the EU, which would place additional pressure on the EU in case of drought during the wheat season.

The findings can enable the development of new risk response strategies and provide the basis for more efficient allocation of resources to contingency plans and strategic crop reserves to enhance the resilience of the global food system.

References

[1] Gaupp F, Hall J, Hochrainer-Stigler S, & Dadson S (2019). Changing risks of simultaneous global breadbasket failure. Nature Climate Change 10: 54-57.