Sure but I think climate change is just one of many variables that show how our global society is fragile - the direction of my proposal would go a long way towards making it much more robust, isolation from climate change is just one problem solved by it. It becomes easy to quarantine/filter access preventing biological contamination. Even on city level you can have isolated blocks further limiting the impact of catastrophic events.

I think the "preserve the environment" is a knee-jerk driven by the same kind of instincts that sell "natural organic food" and stuff - even if we could somehow magically reign in man made climate change there's really no guarantee that the climate will remain stable or that a low probability event like a volcanic eruption won't cause a huge global crisis, etc.

Instead of hoping things remain as they are we should limit our exposure to environment risks.

Another problem I see with your approach is that it tends to favor the rich countries in an extreme way over the poorer ones (assuming it could be pulled off at all), which I think is the final move in the 'externalization' game, let the rest of the world die so that the remnants of Western civilization can go and colonize an otherwise empty world at some point in the far future.

It's a problem if you're looking for a global solution, but even the poor countries would benefit from R&D breakthroughs.