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 not, to our knowledge, been mapped systematically in the frequency domain. This study delivers, to our knowledge, one of the first multi-oscillation cross-spectral analyses of the climate–food price nexus, matching 7 climate indices across the Pacific, Atlantic, and Indian Ocean basins with 5 disaggregated FAO Food Price Index sub-components over 432 monthly observations (1990–2025), verified through 6 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—one of the cleanest actionable climate–price signals documented to date. The Indian Ocean Dipole leads prices by roughly one to two years (cross-correlation peak at sixteen months, though the peak is broad and not sharply localised within that window), extending the early warning horizon well beyond the ENSO signal. The apparent Atlantic Multidecadal Oscillation–price correlation (r ≈ +0.60) is revealed to be a common-trend artefact. Vegetable oils are the most consistently climate-exposed commodity chain across the seven oscillations; sugar and meat, often assumed less climate-sensitive, in fact show strong coherence with specific oscillations (sugar with the Indian Ocean Dipole and meat with the Southern Oscillation Index), indicating that commodity-level exposure is oscillation-specific rather than uniform and reflects each commodity’s position in the production-to-consumption chain—short-cycle, thinly buffered commodities transmit weather shocks to price quickly, while feed-market intermediation delays and smooths the pass-through for livestock. 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 towards Sustainable Development Goal 2 (Zero Hunger).