Do you mean that people need to see how their life will get worse before they will be willing to act? That sounds a little accelerationist to me. But I’m not entirely sure of your argument. You seem to be saying that people would not be worried if they lost 4/5ths of their arable land, but I think I must be misunderstanding something.
(I think it’s s tributary to the Gulf Stream that is at risk of collapsing, not the Gulf Stream itself, which, I’m told, is based on the earth’s rotation rather than climate.)