evidence: With regards to sea level rise, recent U.S. national assessment reports have included a worst-case sea level rise scenario for the 21st century of 2.5 m. Extreme estimates of sea level rise rely on RCP8.5 and climate model simulations that are on average running too hot relative to the uncertainty range of ECS. The most extreme scenarios of 21st century sea level rise are based on speculative and poorly understood physical processes that are hypothesized to accelerate the collapse of the West Antarctic Ice Sheet. However, recent research indicates that these processes are very unlikely to influence sea level rise in the 21st century. To date, in most of the locations that are most vulnerable to sea level rise, local sinking from geological processes and land use has dominated over sea level rise from global warming.