Sea defences, sea levels and climate change

Climate change figures the States of Jersey like to quote suggest a 70cm sea level rise by 2070, plus of course increased storm surges. That's based on the Hadley Centre study using models and data from around 2002. It doesn't sound too much does it, around a centimeter per year average. Unfortunately its not likely to happen in the implied gradual way. There are often sudden events where a large ice shelf or part of a glacier breaks away quite suddenly. Sea ice melting doesn't add to sea level rise appreciably, but land based glaciers like Greenland do.

That 70 cm figure was a good guess based on the models and data available on 2002. Back then the IPCC figures suggested Arctic sea ice would disappear around the end of the century, and it would be decades before the North West passage opened up. Well it actually opened up this year. Reports like the big melt (http://www.carbonequity.info/docs/arctic.html ) show that ice is melting many many times faster than was predicted back then. They also imply the Greenland glaciers are also melting much faster too. That 70 cm(2 feet) figure is much closer than our planning allows for, some would say only 20 years.

I have reason to believe not a few of our States members are interested in boats. Exempting marine fuel from the latest tax rise, testifies to that. So at least one or two of them must have been down to the harbour and marina and observed how close to the top the sea gets on a high spring tide. Two feet added to that and what do you have: a flooded area at least as far as the town church and right through the current underpass.

We urgently need to update our planning assumptions on sea level rises to more realistic figures and feed those back into a review of critical impacts, like whether our sea defences are up to it.

2 comments:

To Zero said...

What's your opinion on nuclear power? Couple that with hydrogen fuel cells and the whole linkage between greenhouse gases and energy production/use breaks down.

Mark Forskitt said...

I dislike nuclear intensely. The consequences of a serious error are too severe. Also I am deeply unhappy about the spent fuel disposal problem. The timescales are just far too long for us to be able to be confident about our plans.

On the shorter timescale there is a question over how much extractable uranium there is for fuel the reactors.

Having said all that I do think Monbiot has a point the immediate danger of climate chaos is collosal. Is it defensible to avert an immediate danger with a longer term one? If we dont get on top of climate chaos then there is no long term problem for humanity with nuclear, the will be too few of us left.

In reality, the timescales for commisiosning and constructing new nuclear and developing a large scale fuel cell industry won't make enough impact quickly enough to make a big difference now. Locally on the same timescale we would be able to make a huge contribution by having large scale marine turbine systems, Like Strangford Lough. There is enough potential to export energy to europe.


I think the only way is for us short term is to get our heads round making changes in our lives - smaller, simpler, smarter, smilier.