The climate emergencyClimate emergency now represents one of the most critical challenges of the twenty-first century, whose widespread impacts on food systems pose significant risks to global food securityGlobal food security, human health, and environmental sustainability. It focuses on the sensitivities of crop production, livestock, fisheriesFisheries, and aquacultureAquaculture concerning extreme events in weather, rising temperaturesTemperatures, changing patterns of precipitationPrecipitation, and intensification of pests and diseases. This chapter explores the extent to which climate-mediated disruption to agricultural productionAgricultural production, floodsFloods, heatwaves, and increasingly powerful storms threaten food supply and access and intensify inequalities within social and economic spheres for people of low-income countries who are the most vulnerable. Interdisciplinary, it brings together perspectives from literature related to climate scienceClimate science, agricultural economics, food policy, and public healthPublic health by describing the direct and indirect impact of climate change on the structures defining food systems. Climate changes influence the environmental, social, and economic effects arising within a chain from production through the patterns of consumption, extending to world trade flows. It also explores in depth the many cascading effects of food insecurity, including increased malnutritionMalnutrition, health crisesHealth crises, and destabilization, particularly among smallholder farmersSmallholder farmers, rural communities, and populations with high dependence on climate-sensitive food sources.