Is Sea Level Rise Really a Big Deal?

  • Published on March 3rd, 2010

crashing waves

When last weekend’s Chilean earthquake sent people across the Pacific rim scrambling to deal with the risk of a tsunami, there was an added danger.

It was a “King Tide” – the location of the sun and the moon meant their gravitational pull was at its maximum. That, combined with the warmth of the ocean water (warm water expands), meant that low-lying areas were in even more danger of being swamped.

The Chile quake tsunami ended up being pretty mild, but this just highlights a question that most people don’t think about: Why is sea level rise such a big deal?

The question

You’ve probably seen estimates like this:

World sea levels rose 3.1 millimetres (about a tenth of an inch) per year from 1993 to 2003, according to the UN’s Intergovernmental Panel on Climate Change (you remember them – they shared the 2007 Nobel Peace Prize with Al Gore). Extrapolating forward, the group estimates global sea levels will rise between 9 and 88 cm (between about 3 inches and three feet) by 2100.

Doesn’t sound like much, does it?

There are some very good reasons you SHOULD be concerned.

The law of averages

Consider: If I told you we could keep your house at an average temperature of 72 degrees, you’d be pretty happy with that, right? That’s a comfortable temperature.

But if I told you that the average temperature would be 72 degrees, but in some parts of the house, the temperature could drop to 32 degrees, and other places would sometimes hit 212 degrees for a few minutes at a time, that wouldn’t be so good, would it? That’s far from comfortable – in fact it’s dangerous.

Averages are funny that way.

… A 2006 study by Australian oceanographers found the rise was much higher, almost one inch every year, in parts of the western Pacific and Indian oceans.

“It turns out the ocean sloshes around,” said the University of Tasmania’s Nathaniel Bindoff, a lead author on oceans in the U.N. reports. “It’s moving, and so on a regional basis the ocean’s movement is causing sea-level variations, ups and downs.

So while the average isn’t enough to cause concern, it’s the extremes we have to worry about – and there, things are getting kind of crazy.

Waves are getting bigger

When you put more energy into a system, you get… more energy in the system.

Just a few years ago, the maximum wave height during winter storms that was expected to hit the Oregon coast was 33 feet. That’s enough to cause serious damage, but people can prepare for it.

But a new study was just completed, and it showed the maximum was up to 46 feet! That’s a 40 percent increase – and it means that all the preparations people have been doing for the past 100 years to protect themselves are useless. There’s a good chance that killer waves will hit sometime in the next few years – eroding coastlines, and smashing docks, houses, and sea-side industries.

And we’re just getting started. The non-partisan Cayman Institute estimates that the cost of rising oceans over the next 40 years will hit an incredible $28 trillion dollars. Most of the mega-cities around the word are seaports, and rising waters of even just a few feet will have a huge impact on port facilities, beachside hotels and resorts, public buildings, and private housing.

For the U.S., the Heinz Center figures that just from homes lost to coastal erosion we’re looking at $530 million per year.

Arctic melting may add to that cost as well.

-> Next page: It’s happening now

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About the Author

Jeremy Bloom is the Editor of RedGreenAndBlue. He lives in New York, where he combines his passion for the environment with his passion for film, and is working on making the world a better place.