[dTal]

A comforting thought for this sort of thing is that it would have happened naturally already, if it were possible at all. We can assume that we're broadly in a 'low energy state', and there's no tiny change that will cause a massive permanent shift. Similarly, Ice-9 can't be real or Earth would be covered in it, and we weren't going to set the atmosphere on fire at Trinity because Earth's already been hit by huge asteroids that didn't.