I think the mass movement of people because of climate change will lead to widespread civil unrest in previously peaceful countries. Europe will be hit hard.
The question of border control needs to be addressed sooner rather than later, because if unlimited immigration continues, then how is solving climate change even feasible?
We keep bring more people into these countries, where do these resources come from to support them all? Oil isn't free. Meat isn't free. I haven't seen any study that says immigrants are anymore likely to "go green".
In my country, the government is planning on increasing the population to 100 million by 2100. But at the same time, they also want to push more Carbon taxes. Like, this stuff doesn't add up but I'm still expected to pay for it all.