Wednesday, April 16

A 1.5 metre sea level rise and us

Recently two different scientific teams (Stefan Rahmstorf in Germany and Svetlana Jevrejeva in the UK) predicted that sea levels will rise between 0.5m and 1.5m by 2100. There are many predictions about sea level rises, including conservative IPCC predictions and scifi scale predictions that are much greater (naming no American names!).

This may seem irrelevant to anyone living in and around Waterlooville. Why would a 1.5m rise on the Solent coast have anything to do with people living on high ground at Waterlooville?

Well if you look at any maps that show the effects of different increases in sea level rises, you will see that even for small rises, the Solent coast starts looking a lot different when compared to other areas of the South Coast. With a 1.5m rise, Portsmouth in particular doesn't come off very well. Anyone living near Eastern road is probably going to have salt sea water permanently lapping around their front door and in their living room. In fact large chunks of the Portsmouth coast line will move inwards, covering streets.

OK so far, chunks of Portsmouth will be under salt water, is this all we have to worry about?

Well no, one obvious problem would be sewage, you can't have sea water getting into the current sewage system. So thats one problem. But that is relatively minor (Yes really, it is!). The main problem is that the sea isn't so benign that it will happily stay 1.5 metres higher than it is now. The next problem is the tide. What appears to be a minor problem of water permanently flooding a few roads, becomes a serious problem of flooding on a larger scale at regular times. So not only do you have people flooded out permanently, but also a greater number of people flooded a number of times a year by the tides.

That's not all. Regular tides are predictable, although probably not manageable without significant defenses. A bigger problem of a 1.5m rise for the whole of Portsmouth is the weather. Storms, surges and high tides would occasionally combine to flood great chunks of Portsmouth. If all these factors are combined then anyone living near the sea in Portsmouth would have to move. Those living on slightly higher ground would also have to move due to tidal flooding, those nearer the central areas will get fed up with the sewage polluting the homes and roads, as well as the weather related flooding.

Where does this all lead to?

Well Portsmouth City council statistics show the cities population being about 196,400 people in 2006. That is a lot of people who will need to move in the next 80 to 90 years. Yes, just 80 to 90 years. Anyone born this year is likely to see this happen in their life time. Even if only 50,000 have to move, that is a lot of people to accommodate in the local area or across Hampshire. If the whole lot move (and that doesn't include other coastal areas in Hampshire), then we have a serious problem.

How does this affect Waterlooville? Well maybe one of the obvious places to go when you're flooded out is nearby higher ground. The pressure to build even more houses in the area will be even greater. You would also have to move businesses, schools etc. The whole thing would be environmentally devastating and extremely expensive.

There are various scenarios that are possible. The first is that because the sea level rise would be relatively slow, the migration from Portsmouth will be gradual and people will even move out of Hampshire. The second possibility is that the government will spend huge amounts of money and put up massive sea defenses, something like New Orleans where much of Portsmouth would be below sea level. This may just put off the inevitable though?

However you look at the issue, Portsmouth and the surrounding area could have some serious problems to deal with in a relatively short time. The whole coast of Hampshire may very well become an economic dead zone, which will also propagate throughout the UK

Some useful links:
Proudman Oceanographic Laboratory
Potsdam Institure for Climate Impact Research
CReSIS Northern Europe Map

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