The ice sheets seem to be shrinking 100 years ahead of schedule.
If humans weren't here and we didn't care about anything that lives here, if this were a video game, I'd push the button and see what happens, because it'd be really exciting; but it's not a video game.
The more the climate is forced to change, the more likely it is to hit some unforeseen threshold that can trigger quite fast, surprising and perhaps unpleasant changes.