What truth is behind the idea that our coastal cities are going to drown?  Yes, there has been a noticeable increase in the average sea level…  But that increase is huge, roughly an increase of 2.77 millimeters per year. So how long would it take to duplicate the history channel Armageddon week image?

Well, let’s make it easier, let’s specify a 3-5 meter sea level rise, so we’ll call it 4 meters.

For calculation purposes, we’ll assume sea level rise to be linear, and round-up the Battery Park tide gauge rate to 3.0 mm per year, which puts it closer to the 3.1 mm per year measured by satellite and published at Colorado State University’s Global Sea Level Page.

• 4 meters = 4000 millimeters
• 4000 millimeters /3.0 millimeters per year = 1333 years

Or for the History channel image above…

• History Channel photo submersion = 20 stories
• Story height = 3.9 meters
• Sea Level Rise in the photo 20 x 3.9 meters = 78 meters
• 78 meters = 78,000 millimeters
• 78,000 millimeters / 3 millimeters per year = 26,000 years

I am feeling just a little safer knowing this.  Of course, this is working under the assumption that the water level rises will be linear…

Well, the 2.7 millimeter rate is the averaged graph shown here, the growth is well contained and it seems like a reasonable figure for the near future.  But let’s speculate a little.

Let’s say it becomes 10 mm, that would be one centimeter a year.  And roughly 400 or 7800 years.  Even if we increased the figure to 50 mm or 5 centimeters a year, that would be 80 or 1560 years…

Please keep in mind, I am not saying that sea levels are not changing.  I have seen that they do, what I am saying is to be aware of the real rate of changes, and be aware of the time scale that we are discussing.

Many of the details in this article is from Freaking out about NYC sea level rise is easy to do when you don’t pay attention to history?