There is an article out about what killed the Neaderthals.
Apparently it was us!
The article lists "climate change" as one of the likely major factors in the demise of the Neanderthals: They were suited for colder climates and when the globe started warming, they were ill-adapted to survive.
So how does this implicate us? It's obvious: Since global warming/climate change/manbearpig is anthropogenic, we must have invented a time machine to divert all our greenhouse gasses to the past, where they wiped out the Neanderthals and set the stage for modern humans to take center stage.
So, future us allowed primitive us to evolve into now us. We're sort of our own grandpas and grandmas. Like in Alabama!