“This extreme rise scenario, considered unlikely but increasingly plausible, was published together with other projections in a technical report by the National and Oceanic Atmospheric Administration in January. NOAA added “extreme” as a new sea level category in the publication, supplementing high, intermediate and low categories that have also been used in past reports”
Extreme Sea Level Rise and the Stakes for America | Climate Central
The “extreme scenario” has nothing to do with the real world. Sea level rise is not accelerating and is below the low scenario.