This briefing paper explores how the failure to tackle climate change threatens all aspects of food security – availability, access, utilisation, and stability. The changing climate is already jeopardising gains in the fight against hunger, and the authors argue that looks set to worsen. Climate change threatens the production and distribution of food, people’s ability to access food by undermining livelihoods and destabilising prices, and damages diets by harming human health and putting at risk the quality of food produced. Finally, the paper sets out how these impacts can be averted, through urgent action to avoid dangerous climate change, address problems in the food system, and strengthen its resilience.