Quantify the impact of climate change on staple crop yields across major agricultural regions through 2050, and estimate the resulting food security gap measured in calories, protein, and micronutrients for the most vulnerable populations.

Integrated assessment model combining IPCC climate projections (SSP2-4.5 and SSP5-8.5) with GAEZ crop suitability models across 180 countries. Yield impacts estimated for wheat, rice, maize, and soy — four crops representing 60% of global caloric intake. Population-weighted hunger gap calculated using FAO nutritional adequacy thresholds, disaggregated by income quintile and region.

1% — with much larger regional losses in Sub-Saharan Africa (-18% maize) and South Asia (-12% wheat). 5, losses double or triple. 5°C due to heat stress during pollination: a single extreme heat event during flowering can eliminate an entire harvest.

The number of people facing severe food insecurity is projected to increase by 80-120 million by 2050 under moderate scenarios — with the burden falling almost entirely on populations already below the poverty line. Nutritional quality, not just calories, is also declining: elevated CO2 reduces protein and micronutrient density in staple crops by 3-17%.