Living in Manhattan and having experienced the storm tide during Hurricane Sandy, I have been reading up on the what climate change is doing to the sea level. Sea levels in the 20th century rose faster than in the 27 (!) centuries before that. A new paper is now suggesting that the rise in the 21st century could wind up being 3 feet. That would be enough to put water on a our doorstep during every high tide and of course devastating for many low lying islands around the world. Sadly, the latter doesn’t seem to move politics in the United States much but change on the East Coast will.

As it turns out those may be even more dramatic. The reason is that at present the Gulf Stream removes a lot of water that would otherwise pile up here. As a sailor I know that tides and ocean currents are powerful but even I was blown away by how strong the Gulf Stream is. According to some models it reduces the water level on the East Coast by as much as 3 feet relative to stationary. At first you might think that’s good news because the Gulf Stream is protecting us by keeping water away. But here comes the problem: meltwater run off from Greenland is slowing down the Gulf Stream which means that water is suddenly backing up on the US East Coast.

How bad is this effect? The answer from this must-read blog post on the coming “Frankentides” is pretty terrifying.

Over the past few weeks, a freak series of high tides inundated large sections of the U.S. East Coast. In Charleston, South Carolina, on October 27, a high tide peaked at 8.67 feet above mean low water. That’s the highest tide for Charleston since Hurricane Hugo roared ashore in 1989. But in this case, there was no category 4 hurricane. Just a ridiculous amount of water flooding in from the ocean. In Savannah, Georgia tides ran 10.43 feet above mean low water on the same day. Again, no storm, just a rising ocean flooding out roadways and inundating homes and neighborhoods. Only a couple of days later, on October 29th, large sections of Boston Harbor flooded under perfectly blue skies.

What does this mean? The city of New York (and other cities on the East Coast) are woefully under prepared for what is happening. The combination of a high tide with a storm surge (as happened during Sandy) will cause flooding beyond anything we have seen.

Maybe that will finally be the wake up call everyone needs on climate change. Of course by then we will be reduced to massively invasive responses, including various geo engineering approaches.

Update:

A comment suggested that there was no evidence of an acceleration in the rise of the ocean level. It pointed to a blog post which in turn led me to the super interesting Permanent Service for Mean Sea Level, which allowed me to put together the following two pictures.

First here is the rate of rise for the 34 year period from 1940 to 1974

And now here is the rate of rise for the 34 years from 1980 to 2014

This clearly shows a significant acceleration on the East Coast in line with a slowing down of the Gulf Stream.