Working Paper 18
Small Seeds, Thin Markets: Climate Risk, Supply Chains, and the Economics of Sesame from Farm to Fast Food
October 2026
Abstract
We trace the full causal chain from climate variability to the economics of the hamburger bun, using the global sesame seed market as the case. World production was 6.68 million tonnes in 2024, concentrated in rainfed smallholder systems across Africa and Asia. Two null results anchor the findings: country-scale weather explains essentially none of yield variation (pooled r=+0.02), and world production changes explain none of US import price changes, because origin substitution absorbs most shocks. A 50% sesame price spike costs the average US McDonald's about $98 per year, but allergen law and rigid supplier approvals make short shortages an operational crisis, not a cost crisis.