Imagine modern technology suddenly disappearing?

The world will no longer be a safe place to live in. Just refresh back on what happen during Katrina. Only a few days without food and drink, the town became chaotic. If we are out of oil, cities will not be able to supply food quickly enough, there will no longer be any shipment of food to the cities. Stored supply will be use up quickly, and we might be forced to eat each other. There are no animals or wild life in cities.