Nuclear famine is what happens when a nuclear war takes place. In a nuclear war, countries or groups fight by using nuclear weapons, which are very powerful bombs that release a huge amount of energy. This energy is so strong that it can destroy huge cities, kill many people, and change the environment.
With nuclear famine, when a nuclear bomb is dropped, it can cause huge fires and make large clouds of radiation. The radiation is a dangerous form of energy that changes the air and soil, and can make plants and animals unhealthy and unable to grow. These radiation clouds can spread over a large area and get in the food people need to eat, which means that the food can be polluted and unsafe to eat. This can lead to people not having enough food to survive, or having food that makes them sick.