A new satellite-based study of the retreating permafrost coastline at Drew Point in Alaska shows that from 1955 to 1979, the rate of loss was only about 23 feet per year. From 2007 through 2016, it was about 56 feet per year.
More info and one-minute video: https://www.washingtonpost.com/energy-environment/2018/11/14/watch-warming-ocean-devour-alaskas-coast-this-striking-time-lapse-video/?utm_term=.20fa6f8e2b42