[ninju]

The concern is the acceleration of the sea level rise

"Whether it takes another 200 or 2000 years largely depends on how quickly the ice sheets melt. Even if global warming were to stop today, sea level would continue to rise."

-- from the same article (2 sentences later)

[lumost]

Given the semi-permanent nature of changes at this point we should likely start talking in rates of change.

7 meter rise over 2 centuries can likely be managed in a reasonable manner via land taxation, resettlement, wall, and levy construction. 7 meter rise in 5 years would likely collapse most of the western world as major population centers find themselves unlivably under water.