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March 25, 2006

Rising Sea Levels A Threat To Coastal Cities Environment

Storm surge floods low-lying coastal city: a true 21st-century story. New Orleans was only a preview. Guardian:

Half of Greenland and vast areas of Antarctica are destined to melt if global warming continues at the same pace until the end of the century, scientists warned yesterday. Their research shows that the loss of so much ice will trigger dramatic rises in sea levels, ultimately swamping low-lying regions of Essex, Lincolnshire and Norfolk and threatening the flood defences of cities such as London, Liverpool and Bristol. The last time so much ice was lost from the poles - in a period between ice ages 129,000 years ago - global sea levels rose by four to six metres.

Experts believe many coastal regions would suffer long before sea levels rose significantly, because even a minor rise will make storm surges more devastating and increase the risk of flooding. A rise of one metre would in effect close the port of London as the Thames barrier would need to be raised for 300 days a year to protect the city, according to one scientist.

The warning comes from climate scientists who combined historical records of Arctic and Antarctic ice melting with advanced computer models capable of predicting future environmental conditions. They found that if nothing is done to put the brakes on climate change, Greenland, the west Antarctic ice sheet and other expanses of polar ice will be warmed beyond a "tipping point" after which their melting is inevitable. [...]

"We showed that that level of warming will come later in this century unless we act on carbon emissions," said Professor Overpeck. "An Arctic warming of 3C to 5C is enough to cause four to six metres of sea level rise."

If temperatures do rise as the scientists predict, the ice at the poles will not be lost immediately. Enough ice is likely to melt within the next 100 years to raise sea levels by a metre, but ultimately the fresh water pouring into the North Atlantic would slow down the Gulf stream, which bathes Britain in warm water from the tropics, by a quarter. "These ice sheets have melted before and sea levels rose. The warmth needed isn't that much above present conditions," said Dr Otto-Bliesner.

The major concern is that unless climate change slows down significantly, the eventual loss of polar ice and subsequent six-metre rise in sea levels will be unavoidable. "There has been an increasing number of observations from the ice sheets suggesting they are responding faster to climate change than anticipated. Now along come our results showing these kinds of changes occurred in the past and lead to large ice sheet retreat and sea level rise. There's a threshold beyond which we'll be committed to this melting and sea level rise irreversibly in the future and that will come later this century," said Prof Overpeck. A one-metre rise in sea level would see the Maldives disappear, make most of Bangladesh uninhabitable and put cities such as New Orleans "out of business", according to Prof Overpeck. The research is published in two papers in the US journal Science today. [...]

Carbon dioxide levels in the atmosphere stand at around 380 parts per million, but many scientists believe they will rise to 550ppm by the middle of the century. "If we were to experience a rise of one metre [in sea levels], we would have to improve sea defences around the country and that would be extremely costly. We wouldn't be able to use the port of London because the Thames barrier would have to be closed for much of the year," said Professor David Vaughan, a climate scientist at the British Antarctic Survey in Cambridge. [Emphasis added]

Republicans say we can't do anything to limit emissions because that would be bad for business. As if losing a bunch of coastal cities and ports will be good for business.

A core problem is that our existing commercial and governmental institutions have a short term focus. No one gets anywhere in business or politics by worrying about problems that are a few decades off in the future. But some problems just aren't short term problems.

[Thanks, Jeff]

Posted by Jonathan at March 25, 2006 08:52 PM  del.icio.us digg NewsVine Reddit YahooMyWeb

Comments

For a good laugh, view the following PDF: http://www.ncr-web.org/downloads/Thonon.pdf. Pages 8 and 9, but start at page 1 (it’s really a slide show, almost no reading). It’s a gut buster.

The Netherlands "Room for the River" policy is actually a good example of politics, business and environmental concerns all coming together at the same table in an attempt to avoid the inevitable - major climate changes on sea levels and rivers and their effect on humans. At least the Dutch are facing the facts, listening to scientists and are making an effort to avoid catastrophe along the Rhine River. These are the world’s expert hydro engineers that are saying man can no longer control the Rhine with all its dikes, damns, levees, basins and flood channels. The Dutch government has allotted hundreds of millions of dollars just to relocate businesses and families situated along the Rhine.

What's one of the biggest obstacles facing this policy? People along the Rhine not wanting to move.

Man, not quite fully evolved.

Posted by: Jeff at March 27, 2006 04:59 PM