[throwawaylinux]

> Given this, I very urgently desire solutions that DON'T take 500 years to work, because if those are all we can come up with, then we might as well not bother: this civilization of ours is doomed sooner rather than later.

You keep coming back to that, but it's a strawman. I did not say that is the solution. My hypothetical 5% was just to say that so many difficult problems would suddenly become easy ones.

There is no one solution, there won't be a mere handful of solutions. There will be (and are) many many efforts and they won't "solve" it, they will make some things better and make others less bad. So anything will help, anything is better than nothing. Reducing population growth from 20% to 10% by 2030 means we only have to reduce per capita greenhouse gas emissions by 45% per capita instead of 50% per capita to achieve the same result (to make up some numbers). That's a huge win. And not only does that benefit apply to greenhouse gas emissions, it applies to practically all environmental problems.