Rising Waters Sagging Cities

Walking in barefeet through three inches of water on a bayfront drive may seem like a lark to the young — once or twice in a childhood.  When that water comes in a dozen times, when cars can’t get through, when basements flood, when foundations begin to shift in muddy jelly, it’s no longer fun.

The Union of Concerned Scientists released a report today based on tidal gauges in 52 sites along the Atlantic and Gulf coasts that not only show a marked increase in coastal flooding since the 1970s but project much more.

From the Executive Summary:

To analyze how often flooding now occurs at locations along the East and Gulf Coasts—and the frequency and extent of flooding that communities along these coasts can expect, on average, 15 and 30 years from now—we relied on 52 tidegauges from Portland, ME, to Freeport, TX. We limited our analysis to locations where flooding thresholds, defined at the gauges, correlate well with coastal flood advisories issued by the National Weather Service.

Annapolis, MD, in December 2012, when wind, rain, and high tides combined to cause disruptive flooding

Annapolis, MD, in December 2012, when wind, rain, and high tides combined to cause disruptive flooding

Our analysis shows that many East Coast communities now see dozens of tidal floods each year. Some of these communities have seen a fourfold increase in the annual number of days with tidal flooding since 1970.

Using a mid-range scenario for future sea level rise, we find that, by 2030, more than half of the 52 communities we analyzed on the East and Gulf Coasts can expect to average more than two dozen tidal floods per year. The rise in the frequency of tidal flooding by 2030 represents an extremely steep increase for some, and two-thirds could see a tripling or more in the number of high-tide floods each year.

Executive Summary

Al Jazeera has a good report

Or, as the Washington Post, eye on local concerns, has it:

Daily flooding caused by high tides will occur in the District and Annapolis within three decades as sea levels continue to rise due to global warming, a new study says

Seas Fall, Seas Rise: What Might We Expect?

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Interesting graphic to accompany this NY Times article about fossil hunting around the world to see how high the seas have risen in eons past.  It just so happens that this shows a slice of American red-state country where disbelief runs deep in higher tides.   I wonder if some strategic billboards up and down the highways with this map would change any minds?

“In previous research, scientists have determined that when the earth warms by only a couple of degrees Fahrenheit, enough polar ice melts, over time, to raise the global sea level by about 25 to 30 feet. But in the coming century, the earth is expected to warm more than that, perhaps four or five degrees, because of human emissions of greenhouse gases.”

 

NY Times