November 2009

Here's my idea for solving one of the symptoms of global warming : Sea Level rise.

I thought of this idea years ago.

No-one seems to have thought about it - but it is a possible solution to one symptom of temperature rise - namely sea level rise. Geo-engineering - but with fewer potential side-effects...

The sea level is rising - and it will continue to rise until we get the atmosphere balance right - 100 years? maybe. So what do you do in the mean time to prevent the Maldives etc drowning? Answer - give the water somewhere to go.

The rise in sea level is 2mm per year (200mm per century) and it's pretty easy to work out what that volume is (it happens to be about 720 cubic kms/year). How do you stop it rising? Simple - dredge holes in the sea bed and dump the spoils on land. (Alternatevely dig big holes on land, creating yourself a mountain(s) and then let the sea water flow in from the coast). Basic idea, create raised land and allow the sea water to fill up the hole left. Whoohoo - more beach front property!

The sums show that this is quite doable - you do have to find land to do this and that would need environmental review of course - how about some desert areas? Sand is quite easy to move. Maybe create some islands in the shallow area off the coast - how about raising the land area of Bangladesh? We have plenty of time to do the work.

The machinery to dig is available - and say we over do it and the sea level falls too much? just reverse the process.

Here are some calculations :

Surface Area of the Planet (510,066,000 sq km) (google)

Total Water Area (361,419,000 sq km) 70.9%

current sea level rise - 200mm per 100 years, 2mm per year (wiki)

Assumptions - that 2mm is spread evenly over all the oceans and we ignore lakes.

Volume of added water 2mm * 361,419,000sq km -> 2/1000 * 1/1000 * 361419000 = 723 cubic kms per year

It doesn't matter if the sea level rise is due to melting ice or to thermal expansion, the effect is the same.

720 cubic kms is a hole 100km by 100km dug to a depth of 72 meters. Of course multiple smaller areas would work too.

You have to do this every year but it is not impossible. Check out existing open cast mines - the one in Zambia is 30 kmē and up to 400m deep - even the developing countries could be encouraged to dig mines etc - very little expertise and lots of employment.

It's entirely possible to treat the sea level rise symptoms of global warming. It would give us some breathing space while the much more difficult task of treating the cause is sorted out. It would be relatively cheap and would not have any worrying side effects unlike the proposed 'cloud whitening' or 'spiking the atmosphere with sulfur compounds' or 'dumping iron into the oceans'.

Fun stuff:)

mike