Scientists Raise Alarm Over Risk of 'Synchronized' Global Crop Failures

Scientists are raising alarms about the risk of simultaneous crop failures occurring in multiple regions across the globe as a result of human-driven climate change, a catastrophe that poses an underestimated threat to the global food supply, reports a new study.

Using sophisticated climate models, researchers zeroed in on the effects of the jet stream, a system of rapidly flowing winds in the atmosphere, on heat extremes around the world. The results revealed that “meandering” jet stream patterns can produce weather anomalies in some of the most important crop-producing lands on Earth, an ominous signal that “synchronized” harvest collapses could occur in the future.

Climate change, which is driven by human consumption of fossil fuels, is placing enormous new pressures on humans and other lifeforms on the planet. In particular, rising temperatures are fueling more intense extreme weather events, such as heatwaves, droughts, floods, wildfires, and storms, all of which have adverse effects on food production worldwide. Given that disruptions to the global food supply can be deadly, especially for import-reliant nations, scientists have been galvanized to better understand the complex risks that climate change poses to global crop yields.

To that end, scientists led by climate scientist Kai Kornhuber from Columbia University’s Lamont-Doherty Earth Observatory set out to study meandering jet streams, which are especially wavy wind patterns in the sky that have remained a wild card in climate and crop models. 

By analyzing climate data collected from 1960 and 2014, the team discovered “an increased likelihood of concurrent low yields during summers featuring meandering jets in observations and models” which expose “high-risk blind spots” in climate models, according to a study published on Tuesday in Nature Communications.

“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,” said Kornhuber and his colleagues in the study. “Thus, 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.”

“While climate models have been excellent in projecting the mean response to continued anthropogenic greenhouse gas emissions our analysis suggests that they might provide a conservative estimate of how concurrent extreme weather events driven by specific circulation regimes might evolve in future and how they might affect regional crop yield and covariability across regions,” the team added.

Climate models and projections have become extremely sophisticated in recent years, but it’s still challenging to account for all of the effects caused by the collision of natural climate cycles with human activities, such as the burning of fossil fuels. 

For instance, Kornhuber and his colleagues note that the intricate relationship between jet stream patterns, extreme weather events, and crop yield anomalies has only been quantified on a regional basis, rather than a global level. Up until now, there has also been a lack of clarity about how shifts in these atmospheric wind patterns could affect crop yields in the future.

The team’s 54-year dataset showed that meandering jet streams have the potential to trigger far more devastating heat extremes than previously realized. The researchers also generated projections for the latter half of the 21st century that show an elevated risk of simultaneous crop failures that could cripple the global food supply chain by triggering crop failures in key breadbasket regions such as India, the United States, and Eastern Europe.

In other words, the new study offers a frightening glimpse of a world roiled by food shortages brought on by meandering winds. As with all other warnings about climate change, the only chance at avoiding this fate is to drastically reduce humanity’s consumption of fossil fuels within the coming years.

“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, supplemented by expert elicitation, qualitative storylines, and decision-centric approaches,” the researchers said. 

“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,” they concluded.