> You're wrong. If we did that [spread manmade climate change over next millennium], meltwater water supply would essentially stop (in somewhere between 8 months and 2 years), everywhere on the planet.

What exactly are you talking about here? Meltwater amounts would be roughly the same compared to the last millennium, until glaciers start vanishing (only, in that obviously favorably scenario, in 500ish years instead of this century).

I get the impression that you think that manmade climate change is somewhat helpful compensation for natural trending towards ice age. This is not the case at all, because the rate of change is too high. See https://xkcd.com/1732/.

A (natural) looming ice age is not problematic or threathening at all because that happens so slowly that we get many centuries to act.