What is the wave effect of a 50 cm rise in sea levels?

On the ABC’s 7.30, climate scientists in Antarctica predicted a 50 cm rise in sea levels by the end of the century. There were pictures of the melting ice. They are spectacular, but we have seen them all before.

nasa-out

Now 50 cm doesn’t sound like much. It’s about the height of the desk I am sitting at now. So try to think of what that means in terms of the local beach. It simply means that the tide comes in a bit more.

But surely that can’t be right, that doesn’t sound all that serious.

I remember Asian students in my systems classes at Monash regularly defining the most serious problem that they would face being changing sea levels. Not economic, social or political problems but changes in sea levels. Those will come later.

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Children play in the remains of an abandoned building in a flooded district in the northern port area of Jakarta. Almost 40% of Jakarta lies below sea-level

This was across-the-board, not limited to one specific national group. And I’m talking nearly 15 years ago.

These were young 20 year old students and they were very worried. They said the problem was at its worst when the tide came in which meant every day.

And this is why is a 50 cm rise so disastrous.

So it helps to think in terms of a baby’s bath tub that is three quarters full and you put some more water in.

Let us assume that this diagram illustrates a 50 cm rise in sea levels.

Give the bath tub a little rock to create a wave. This wave is similar to the gravitational effect of the moon, creating tides.untitledWhat the 7.30 program did not tell us, and I certainly don’t know, is how big the wave will be.

You can do a little experiment with a tray of water. Try carrying it across the room. The waves get pretty big.

So I suspect that the problem is that much of the low-lying areas of the globe will be eventually be subjected to tsunamis every time the tide comes in.

coal

“This is coal it won’t hurt you”

 

 

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