The future, it seemed, was turning out to be one damn thing after another. - Stephen Baxter

Cause and Effect, when Time Machines are about, are rather awkward concepts.

There was a great wave of extinctions that, ultimately, couldn’t be stopped. How bad was it? Well, Oona, we don’t really know. We didn’t even get as far as counting all the species before destroying them. Yes, that’s right; a lot of species must have died out before we even knew they were there. Shivery thought, isn’t it?

“So that’s that,” Miriam said. “We have a plan.”
“You have a shared delusion,” I said.