This chapter explores threats to food security. It reveals many challenges arising from a range of threats external to the farm household, including severe biological threats from pests, disease, and weeds. Moreover, healthy, fertile soils are the cornerstone of food security and rural livelihoods, but African soils are degrading. Water is just as important for the productivity of plants, and lack of water leads to chronic and acute stress. Indeed, Africa is already battling the impacts of climate change. Rising temperatures and variable rainfall are increasing the exposure of smallholders to drought, famine, and disease. Agriculture is an important emitter of greenhouse gases (GHGs), not only carbon dioxide but also such powerful gases as methane and nitrous oxide. In addition, there are often severe socioeconomic challenges, including unstable and high prices of basic commodities. Finally, conflicts cause disruption to food security.