Question: how long till utter distruction of wildlife?

Dave Underhill answered on 11 Jun 2019:

I’m glad this cropped up here. Personally, I do not believe there will be the utter destruction of wildlife until trees become unable to photosynthesise. Estimates suggest that this will be in approximately 600 million years – 1.2 billion for plants that photosynthesise heavier carbon, and even then it is only if they do not evolve further and alter how they photosynthesise. Also predicted for about a billion years time is the evaporation of the ocean, and this too would have devastating consequences. To address the elephant in the room, human influence, it is clear that we will not cause the utter destruction of wildlife because we are presently living in an interglacial and a glacial phase will arrive and restore more of the natural balance. During the Anglian glaciation half a million years ago most of Britain was under a kilometre or more of ice! this kind of expansion in the ice caps would decimate our cultures and technology and be a boon for cold-adapted wildlife. So the answer to the question is about a billion years.