Global Food Security in a Climate-Oscillating World: Spectral Evidence and Early Warning Implications for Sustainable Food Systems

In March 2022, the FAO Food Price Index peaked at 159.7 as climate shocks collided with geopolitical disruption, pushing global hunger past 735 million and exposing how deeply climate variability penetrates the economics of agri-food systems. Yet the imprint of ocean–atmosphere oscillations on global food prices—the central economic signal of the agri-food system—has never been mapped systematically in the frequency domain. This study delivers the first multi-oscillation cross-spectral analysis of the climate–food price nexus, matching seven climate indices across the Pacific, Atlantic, and Indian Ocean basins with five disaggregated FAO Food Price Index sub-components over 432 monthly observations (1990–2025), verified through six robustness checks including surrogate-data testing. Four findings carry direct policy relevance. ENSO indicators lead global food prices by three to four months with a 100% surrogate-test pass rate—the cleanest actionable climate–price signal yet documented. The Indian Ocean Dipole leads prices by sixteen months, extending the early warning horizon from weeks to over a year. The apparent Atlantic Multidecadal Oscillation–price correlation (r ≈ +0.60) is revealed to be a common-trend artefact. Dairy and vegetable oils emerge as the most climate-exposed commodity chains, while meat is buffered by feed-market intermediation. These results provide the empirical foundation for integrating real-time monitoring of climate oscillations into food system governance—a low-cost policy innovation that aligns economic stability objectives with climate adaptation goals, strengthens the resilience of agri-food value chains, and supports progress toward Sustainable Development Goal 2 (Zero Hunger).