If the temperature there continues to climb, does it become migrate or die ?
Yes.
You become stateless if you live on an unfortunate Pacific Island.
Water becomes like oil too in equatorial regions. You get wars breaking out over access to it. Dams which screw up those down river are an issue.
Pretty sure that others in the EU are very concerned about this, and its part of the growing willingness of governments to 'shut up shop' and close borders. Syria is the first big wave thats all. Hence why boats in the Med aren't being rescued anymore too.
Long term, its something political leaders are desparate to avoid talking about because of the unpalatable reality that they will have to manage against domestic intolerance. Especially combined with the technical revolution.
The only certainity ahead is greater political instability because no one is getting a grip on this, and its easier to prioritise racism and a role back on human rights than tackle human rights.
You are also pretty stuffed if you are Dutch because you have too much water but at least you have freedom of movement still.