Try this one...
The 2040s seemed like a turning point. Cheap commercial fusion power headed a series of new tech that brought boom times to the World and seemed to solve the climate change issue. However the wait to act seriously was to long.
West Antarctica started to collapse into the sea in 2051. By 2063 sea level had jumped six meters.
The economy is in chaos. Some small island nations have vanished. Certain vulnerable areas are brutally hard hit. Both the Nile and Ganges deltas are flooded and tens of millions displaced. Europe is hit with internal and external refugee crises. The USA is reeling. Whole states no longer have enough population to be states, but they demand their two senators and representatives!
Basically this is a time of crisis and chaos. The possibilities for PCs and adventures are vast. This world has moved to TL9 and has the resources to deal with this crisis, panic is the main enemy.
Note: West Antarctica is uniquely vulnerable to collapse because the glaciers rest of land below sea-level.