Here's the thing. Nobody knows for sure. Climate changes. The biggest villains are volcanoes and asteroids. It's very easy to blame industrialisation and deforestation, and clearly that will have some effects, but predicting the future has never worked out. Look back at all the crazy predictions over the years.
I suspect that wars nullify any greenhouse gas gains we claim by Millibraining the issues. In the end I think that mankind (personkind), will have to ride the waves of change, as mankind has always done.
