I don't know what your proposed solution is, since you elected not to share it. I will say though that historically, the only examples I can recall of independ

I don't know what your proposed solution is, since you elected not to share it. I will say though that historically, the only examples I can recall of independent polities being able to work together to solve common problems involved both an outside enemy, and a shared set of values, culture, and experience. Global warming doesn't fulfill either criterion. Despite the Internet and modern media, Western culture and values are not universal. And even in the US, a large fraction of the population doesn't even acknowledge that global warming is a problem, much less be willing to pay for a fix. How are you going to get those people to come along without some level of coercion?