Population will not forever grow, this is already forecasted by established scientists.

My point is that countries experiencing lower-than -replacement-birthrate should allow it, with the acknowledgement that climate refugees will come to fill their job positions. Over a longer period, birth rate should continue to be allowed to sink, as future humanity grapples with a post-climate-crisis world.

A far flung generation can have new opinions, when they've survived our sins, mastered technology, and can make a new try

To repeat: I don't think any group should be "reduced" via external pressure. Only that groups could be allowed to contract naturally, without policy intervention to "boost" birthrate. Immigration should serve.