NEW research, by a team of German and US scientists, shows that simultaneous harvest failures across major crop-producing regions would be a major threat to global security. It shows too that these risks are greatly under-estimated.
The researchers are concerned that concurrent weather extremes, driven by a strongly meandering jet stream, could trigger major, simultaneous crop-failures. This would threaten global nutrition, potentially risking regional conflict.
Buckling in the jet stream can lead to high levels of heat and drought to the south and colder, wetter and less settled weather to the north. In both cases, this affects crops and can destroy harvests. Even small simultaneous crop losses can present a systemic security risk.
The researchers say that the ability of state-of-the art crop and climate models to adequately reproduce such high impact events is a crucial component for estimating risks to global food security. However, while climate models accurately simulate atmospheric patterns, surface weather anomalies and the negative effects on crops, the responses are mostly underestimated in bias-adjusted simulations.
“Given the identified model biases, future assessments of regional and concurrent crop losses from meandering jet states remain highly uncertain. Our results suggest that model blind-spots for such high-impact but deeply-uncertain hazards have to be anticipated and accounted for in meaningful climate risk assessments.”
Commenting on the research, ffinlo Costain, founder of the Food & Global Security Network, said “This modelling shows the potential for global nutritional catastrophe. When combined with the additional impacts of accelerating biodiversity loss and desertification the picture becomes deeply worrying.
“While this research is important – the response is also critical. Firstly, this wake up call must be heeded by policymakers, but secondly, society needs to respond effectively. If concern precipitates a doubling down of current high energy, fossil-fuel intensive agriculture then this could lead to further devastating impacts on natural systems. A rapid transition to agroecology is needed to combat the food and societal risks of harvest and global commodity-trading failures.”
The researchers say that “extreme weather events like heatwaves, droughts and extreme precipitation can adversely impact crop production and food security. Global warming is increasing the frequency and intensity of weather extremes and the likelihood of their simultaneous occurrence globally. Extremes occurring in close temporal vicinity can lead to outsized societal impacts, often beyond the sum of each extreme occurring in isolation.
“In particular, synchronized crop failures due to simultaneous weather extremes across multiple breadbasket regions pose a risk to global food security and food system supply chains with potential disproportional impacts for import-dependent regions.
“Concurrent crop failures in major crop-producing regions constitute a systemic risk as associated spikes in food prices can lead to conflict and undernutrition in countries that rely on imports.
“Understanding the likelihood of concurrent crop failures, and the degree to which models are able to reproduce observed relationships, is important for increasing the resilience of the global food system and mitigating climate risks.
“Our study points towards potential high-impact blind-spots in current climate risk assessments, highlighting the urgent need for more empirical and process-based research to support model improvements in the climate and agriculture domains.
“Evidence for high-risk blind-spots, such as an underestimation of synchronized harvest failures as identified here, manifests the urgency of rapid emission reductions, lest climate extremes and their complex interactions might increasingly become unmanageable.”