Florence’s flood waters could be half a foot higher, thanks to climate change

https://www.washingtonpost.com/energy-environment/2018/09/13/no-brainer-climate-change-has-made-hurricane-florence-worse/?utm_term=.b8f26e81c2fd

By Chris Mooney and
Brady Dennis


There is plenty of debate among scientists about the extent to which you can blame climate change for ferocious hurricanes. But one thing they do not disagree on is that climate change contributes to sea surge. In the case of Hurricane Florence and the Carolinas, some six inches of the coming storm surge is attributable to climate change because sea levels have risen in the past 100 years or so.
“Essentially, every coastal flood today is made deeper and more damaging by sea-level rise caused by climate change,” said Benjamin Strauss, chief executive and chief scientist at the research organization Climate Central. “The principle is simple: If you fill a bathtub higher, it’s easier for splashes to get out of the tub.”

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Seas have risen about a foot along the Carolina coast since 1900, according to Rahmstorf and his colleague Andrew Kemp, a Tufts University sea-level rise expert who has studied the Carolinas, in particular. (You can also see this in the tide gauge at Wilmington, N.C.) About a third of that change is due to land sinking, or subsidence, which cannot be blamed on humans or climate change. But the remaining amount — about eight inches, or 20 centimeters — is the result of sea-level rise, a substantial part of which is attributable to humans.

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Kopp also said that this is only the beginning — climate change will directly add more and more water to the seas, and the risk that that causes will only increase.

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Sea-level rise is driven by climate change in multiple ways. First, warmer water expands and takes up more space, and seas are warming as well as rising. Second, melting ice from Greenland, Antarctica and smaller glaciers around the world (Alaska, Patagonia and many other places) adds water to the already expanding ocean.
This does not mean that climate change and sea-level rise are the biggest factors determining how much damage Florence will cause at landfall. Many other factors — the storm’s speed and size, the shape of the seafloor and coastline, whether it’s high or low tide, and more — loom larger in determining that.

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