It's very defeatist, but maybe it would make sense to consider emigration before everyone else does so.
But its not about the weather changes per se; its about the global human conflict when food gets scarce and hungry people have guns. You have to survive that first.
In the other extreme I guess a all out nuclear strike on population centres in China and India might have a chance to kill a slight majority of humanity, but I wouldn't bet on it. Conventional weapons offer no real effect here I think.
I don’t want to take away from your other point but this is not so trivial for the hundreds of millions living in low lying countries like Bangladesh.
https://www.berkeley.edu/news2/2010/06/climate-vulnerable.jp...
https://grist.files.wordpress.com/2012/11/4-enviro-econ-impa...
https://www.eea.europa.eu/data-and-maps/figures/projected-im...
tl;dv:
- Canada, Russia, and Northeast Africa (Egypt/Libya) actually see positive impacts. For Canada and Russia global warming could be a huge boon, opening up large areas of uninhabitable permafrost to settlement and bringing in trade through arctic ocean sea routes.
- The US does pretty well, but with large regional variations. The Pacific Northwest and Northeast become more desirable, with fewer rainy days. NorCal does okay but faces increased forest fires. The Southwest (LA/Vegas/Phoenix) faces water shortages. The Southeast becomes a miserable place to live.
- Europe (particularly Southern Europe) is in trouble. Crop yields and rainfall drop in the South; the North is vulnerable to changes in the gulf stream.
- Africa, India, Australia, and island nations get fucked.
So basically, the worst effects fall on the global poor, while major geopolitical powers see mostly neutral (U.S, China) or positive (Russia) effects. Within those neutral countries, the benefits fall largely on rich heavily-populated areas, while the downsides fall on marginalized rural poor. No wonder we haven't seen much movement on fixing climate change.
Canada is a big surprise winner that could catapult it to geopolitical prominence. Right now it's the U.S's friendly northern neighbor; in 2100 it could rival the U.S. in power.
In short, head for high ground far from the equator. Maybe look for places with reasonably strong militaries as well.
I fear I'll be beaten to the punch and my unborn kids will have to figure it out for themselves, though.