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 it looks set to worsen. It threatens the production and distribution of food. It threatens people's ability to access food by undermining livelihoods and destabilising prices, and it 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 our broken food system, and strengthen its resilience.