Persistent Adaptation Policy and National Food Self-Sufficiency: Within- and Between-Country Evidence from a Global Panel

Climate change affects domestic agricultural production, but national food self-sufficiency also depends on institutional and structural conditions that operate over different time horizons. This study examines these relationships using a balanced panel of 101 countries observed annually from 2012 to 2022 (1111 country-year observations). Food self-sufficiency is measured with the Food Self-Sufficiency Ratio (SSR), with SSR > 85% as the primary binary outcome. A pooled logistic regression with a within–between decomposition following the Mundlak approach separates persistent between-country differences from within-country changes, with country-clustered standard errors. The most consistent finding is a positive between-country association between long-run agricultural adaptation-policy status and high self-sufficiency (OR = 6.676, 95% CI: 1.502–29.668), whereas within-country changes in policy status are not statistically significant. This association reflects a persistent cross-country difference and should not be interpreted as a causal short-run effect of policy adoption. Within-country increases in climate-finance scores are negatively associated with the 85% threshold, but this result is sensitive to the outcome definition. Sensitivity analyses using 75%, 80%, and 90% thresholds show that the adaptation-policy association remains positive across all specifications and is the most stable result overall, although it is no longer statistically significant at the 90% threshold. The findings underscore the importance of distinguishing persistent institutional conditions from short-run policy changes when analyzing national food self-sufficiency.