Our Disappearing Shoreline

The cycle of land erosion

Notice in the image above that the sea doesn’t have to rise much for quite a bit of land behind it, the land it newly touches, to erode and collapse. As John Englander points out in this TED Talk (3:36):

It makes sense that every time sea level goes higher, the shoreline is going to move inland. But the ratio is surprising. For each foot of rise, the average global shoreline moves inland about 300 feet — the length of a football field.

Keep that ratio in mind. To answer our original question, one foot of sea level rise moves the shoreline inland by something like 300 feet, or more if you live in a low coastal zone like most of Florida. (...)

When Will We Start?

So no, we’re not safe during “modest” sea level rise. A rising sea level shouldn’t be counted in vertical inches and feet, but in horizontal feet, yards and miles, measured from the previous shoreline to where our towns and cities will be safe for the next 100 years or so.

How long will it take to effectively move New York City? Mumbai? Jakarta? Shanghai? San Diego? Forever, if the planning never starts.

by Thomas Neuburger, God's Spies |  Read more:

Image: Life cycle of a landslide on a bluff composed of sediment (modified from Kelley and others, 1989) via: