Simultaneous yield losses across major producing regions can be a threat to food security but had not been quantified by the time of AR5. Large-scale sea surface temperature  oscillations greatly influence global yield of major crops   and food prices . Some studies showed that crop yields in different regions covaried with SST oscillations, suggesting occurrences of tele-connected yield failures  . Evidence of synchronised crop failures increasing with ongoing climate change is still limited.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report