There is a book written on the reverse of technology back to a stone age existence. Earthship villages in the right locations could be high tech and have year around growing ability. This stuff was around 5 years ago, using the median line of climate change. Now, it has been shown to be going at an accelerated rate 19% over the worst case scenario toward a world 9*C warmer before 2100 with wild card methane release totally beyond control, and a self sustaining process or feedback loop. That amount of climate change in that short a time is not adaptable by 89% of species (estimated). Species humans depend on, gone. We can talk about un-affordable, impossibly quick solutions, but they are fantasies. The most widely available food by 2050 will be human flesh, with polluted water to wash it down.
