In 2018 a persistent wave-7 circulation pattern foreshadowed future threats to world food supplies by creating simultaneous Northern Hemisphere crop decreases.
Rossby Wave resonance creates "stuck" jet stream bends that make drought, heat wave, and flood events last a long time in one area. I go into more detail, describing wave-5 events here.
In sum, Arctic Amplification leads to deep jet stream meanders that control weather across the hemisphere.
This shows how hot and cold zones persisted. Image from paper above.
A new study finds a 20-fold increase in the risk of simultaneous heat waves in major crop-producing regions when the pattern is in place
A just-published December 9 follow-up study, Amplified Rossby waves enhance risk of concurrent heatwaves in majo...--also led by Dr. Kornhuber--found that stuck jet stream patterns like seen in 2018 are prone to bringing simultaneous heat waves and associated drought conditions to multiple important grain-producing regions of the world.
Given the importance of these regions for global food production, the identified teleconnections have the potential to fuel multiple harvest failures posing risks to global food security.” (A teleconnection is a causal connection or correlation between meteorological phenomena which occur a long distance apart).
Until now, this was an underexplored vulnerability in the food system.
... the wave-7 patterns bring heat waves and drought to western-central North America, western Europe and western Asia.
As the Arctic continues to heat up, such large scale wave patterns will become more common. The jet stream is driven by the contrast between a hot equator and cold Arctic. As that gradient decreases, the jet stream slows and wanders similar to the way slow-moving rivers meander more than fast-flowing ones.