What will happen if young people believe the world is ending?

What would happen if young people in OECD countries started believing the world is ending, that humans will be wiped from the face of the Earth due to climate disruption? They would stop undertaking long studies, as they would not receive the higher wages in adult life or a higher pension; They would stop saving, as they would not need to consume after retirement; They would stop having children; They would prefer leisure over work. There are signs today of the last two consequences of this belief in the disappearance of human life from Earth, but not the first two.