Stark Warning: Dramatic New Sea Level Rise Figures

Scientists to issue stark warning over dramatic new sea level figures

Rising sea levels pose a far bigger eco threat than previously thought. This week's climate change conference in Copenhagen will sound an alarm over new floodings - enough to swamp Bangladesh, Florida, the Norfolk Broads and the Thames estuary


With much of the country already below sea level, even a small rise
would be devastating for the Dutch. Photograph: Peter Dejong/AP

Scientists will warn this week that rising sea levels, triggered by global warming, pose a far greater danger to the planet than previously estimated. There is now a major risk that many coastal areas around the world will be inundated by the end of the century because Antarctic and Greenland ice sheets are melting faster than previously estimated.

Low-lying areas including Bangladesh, Florida, the Maldives and the Netherlands face catastrophic flooding, while, in Britain, large areas of the Norfolk Broads and the Thames estuary are likely to disappear by 2100. In addition, cities including London, Hull and Portsmouth will need new flood defences.

"It is now clear that there are going to be massive flooding disasters around the globe," said Dr David Vaughan, of the British Antarctic Survey. "Populations are shifting to the coast, which means that more and more people are going to be threatened by sea-level rises."

The issue is set to dominate the opening sessions of the international climate change conference in Copenhagen this week, when scientists will outline their latest findings on a host of issues concerning global warming. The meeting has been organised to set the agenda for this December's international climate talks (also to be held in Copenhagen), which will draw up a treaty to replace the current Kyoto protocol for limiting carbon dioxide emissions.

And key to these deliberations will be the issue of ice-sheet melting. The International Panel on Climate Change (IPCC) - when it presented its most up-to-date report on the likely impact of global warming in 2007 - concluded that sea-level rises of between 20 and 60 centimetres would occur by 2100. These figures were derived from estimates of how much the sea will increase in volume as it heats up, a process called thermal expansion, and from projected increases in run-off water from melting glaciers in the Himalayas and other mountain ranges.

But the report contained an important caveat: that its sea-level rise estimate contained very little input from melting ice sheets in Antarctica and Greenland. The IPCC forecast therefore tended to underestimate forthcoming changes.

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These revisions suggest sea-level rises could easily top a metre by 2100 - a figure that is backed by the US Geological Survey, which this year warned that they could reach as much as 1.5 metres.

In addition, in September, a team led by Tad Pfeffer at the University of Colorado at Boulder published calculations using conservative, medium and extreme glaciological assumptions for sea-level rise expected from Greenland, Antarctica and the world's smaller glaciers and ice caps. They concluded that the most plausible scenario, when factoring in thermal expansion due to warming waters, will lead to a total sea level rise of one to two metres by 2100.

Similarly, a commission of 20 international experts, called on by the Dutch government to help plan its coastal defences, recently gave a range of 55cm to 1.1 metres for sea-level rises by 2100. "Equally important, this commission has highlighted the fact that sea-level rise will not stop in the year 2100," said Professor Stefan Rahmstorf of Potsdam Institute for Climate Impact Research. "By 2200, they estimate a rise of 1.5 to 3.5m unless we stop the warming. This would spell the end of many of our coastal cities."

This point was backed by Dr Jason Lowe of the Hadley Centre, the UK's foremost climate change research centre. "It is still not clear exactly how much the sea will rise by the end of this century, but it is certain that rises will continue for hundreds of years beyond that - even if we do manage to stabilise carbon dioxide emissions and halt the rise in atmospheric temperature. The sea will continue to heat up and expand. In addition, the Greenland ice sheets will continue to melt," he said.

This latter effect could, ultimately, have a particularly destructive impact. Scientists have calculated that if industrial emissions of carbon dioxide and other greenhouse gases eventually produce a global temperature increase of around 4C, there is a risk that Greenland's ice covering could melt completely. This could take several hundred years or it might require a couple of thousand. The end result is not in doubt, however. It would add around seven metres to the planet's sea levels. The consequence would be utter devastation...cont'd

http://www.guardian.co.uk/science/2009/mar/08/climate-change-flooding

:kick:

K&R

I've lost my bees
The cow's in water up to her knees
The chickens are roosting in the sycamore trees
Three foot high and rising

K&R

Johnny Cash. I think I may have changed it a bit. It's been a while since I last heard it.