I think the worst case is not how much of the world is forest. The worst case is failure of the world agriculture system, widespread famine, poverty, disease, w

I think the worst case is not how much of the world is forest. The worst case is failure of the world agriculture system, widespread famine, poverty, disease, war, death, and eventual failure of the human race. If you're worried about whether stuff will continue to live on earth it's not a big deal. If you're worried about whether humans in particular will continue to live on earth and the parameters of what 'live' means you should be very, very concerned.