We are chopping away at the bottom of the food chain...
Global warming will reduce human food crops, and reduce the nutritional value of what remains...
Rising temperatures will drive mass human migration on a scale that is not only unprecedented, but is impossible to imagine.
The death toll from all this turmoil in coming decades will likely be in the hundreds of millions- if we are very very lucky...
I fear a more likely scenario is collapse of the global civilization - constant war and billions dead. All before the year 2100... The rise of fascism globally will happen long before that- indeed, it is clearly happening now.