I think when you write a story set a planetary scale, it's necessary to translate what to an eponymous hero is a skinned knee falling off a bicycle, in planetary terms is 100m climate refugees dying in the relocation.

And lest anyone think "couldn't happen" a reminder that a significant percentage of the world like 40% or so live within 150km of coastal regions even if not at risk of inundation, for a mix of reasons, that total inundantion risk of most coastal regions less than 5m above mean sea level in the 50-100 year timeframe is high, that at least 150m people live in these regions, and that 'transmigrasi' actually happened: Indonesia decided that for the good of the state, entire cities of people would move. The government owns to 5.5m, the scientists argue up to 8m -they don't own to stats on what is euphemistically called "surplus mortalities" I think.