Collapse This piece of coastal sea cliff is found on Alaska’s North Slope at a location called

CollapseThis piece of coastal sea cliff is found on Alaska’s North Slope at a location called Drew Point. These blocks are a fascinating combination of changing climate and previously frozen landscape. The soil at this site is held together by Permafrost – it is cold enough that there is a soil layer containing year-round ice just below the surface. However, when that permafrost is exposed to the open ocean, it melts rapidly, allowing the ocean to eat away at the bottommost sediments and removing support for the soil above.Once the ocean removes the supporting soil at the bottom, the still frozen soil blocks above break off and collapse downward, where they are suddenly exposed to ocean water. The permafrost then melts rapidly, leaving the soil to be rapidly washed away.Although maps for this location are only available going back to the 1940s, the US Geological Survey is monitoring this coastal retreat. A survey a decade ago found that since the 1940s, the average yearly rate of coastal retreat here has more than doubled, from ~6 meters of retreat per year to 15 meters per year. The survey now has timelapse cameras at this site that monitor the coastal retreat as these blocks break off. Rapid erosion like this elsewhere in the Alaskan Arctic has the potential to threaten both villages and infrastructure for the oil and gas industries.-JBBImage credit: USGShttps://flic.kr/p/RN3XerRead more:https://walrus.wr.usgs.gov/climate-change/hiLat.htmlhttps://www.youtube.com/watch?v=LaB3nKxPjiU -- source link

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