After Us, the Flood.

The brilliant young physicist Henrik and his fellow students develop a fusion reactor that produces endless clean energy, potentially saving Earth from environmental catastrophe. The reactor, however, is harnessed for commercial use, and the consequences for the planet and society are devastating. By the year 2064, the world has been ravaged by climate change. The UN succeeds in developing a form of time travel that can return a person's memories and personality to the moment of birth. Henrik is sent back to the past in an attempt to prevent the escalation of a catastrophe before it is too late. Something goes wrong and Henrik is forced to begin his mission from a very different starting point to the one he is used to.