Enhanced Risk of Multiple Breadbasket Failures Due to Amplified Rossby Waves

In a strongly interconnected world, simultaneous extreme weather events in far-away regions could potentially impose high-end risks for societies. In the mid-latitudes, amplified Rossby waves are associated with a strongly meandering jet-stream and might cause simultaneous heatwaves and floods across the northern hemisphere. A recent example is the summer of 2018 when several heat and rainfall extremes occurred near-simultaneously. We find that some wavenumbers are associated with recurrent circulation regimes and lead to simultaneous heat extremes occurring repeatedly across specific regions. Further, we find that two or more weeks per year spent in the specific wave regime are associated with significant reductions in crop production in affected regions. Given the importance of these regions for global food production, the identified teleconnections might have the potential to fuel multiple harvest failures posing a risk to global food security.