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["Lawrence F. London, Jr." <lfl@intrex.net>]

<http://news.bbc.co.uk/1/hi/sci/tech/4660938.stm>

Last Updated: Monday, 30 January 2006, 11:00 GMT
Stark warning over climate change
By Richard Black
Environment Correspondent, BBC News website

Icebergs in Greenland
The report says sea levels could rise by seven metres
Rising concentrations of greenhouse gases may have more serious impacts than previously believed, a major scientific 
report has said.

The report, published by the UK government, says there is only a small chance of greenhouse gas emissions being kept 
below "dangerous" levels.

It fears the Greenland ice sheet is likely to melt, leading sea levels to 
rise by seven metres over 1,000 years.

The poorest countries will be most vulnerable to these effects, it adds.

The report, Avoiding Dangerous Climate Change, collates evidence presented by scientists at a conference hosted by the 
UK Meteorological Office in February 2005.

The conference set two principal objectives: to ask what level of greenhouse gases in the atmosphere was too much, and 
what the options were for avoiding such a level.

        
It's the irreversibility that I think brings it home to people
Margaret Beckett

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In the report's foreword, UK Prime Minister Tony Blair writes that "it is now plain that the emission of greenhouse 
gases... is causing global warming at a rate that is unsustainable."

Environment Secretary Margaret Beckett said the report's conclusions would be 
a shock to many people.

"The thing that is perhaps not so familiar to members of the public... is this notion that we could come to a tipping 
point where change could be irreversible," she told BBC Radio 4's Today programme.

"We're not talking about it happening over five minutes, of course, maybe over a thousand years, but it's the 
irreversibility that I think brings it home to people."

Vulnerable ecosystems

The report sets out the impacts associated with various levels of temperature 
increase.

        
Greenland heats up

Enlarge Image

The European Union (EU) has adopted a target of preventing a rise in global average temperature of more than two degrees 
Celsius.

But that, according to the report, might be too high, with two degrees perhaps being enough to trigger melting of the 
Greenland ice sheet.

This would have a major impact on sea levels globally, though it would take up to 1,000 years to see the full predicted 
rise of seven metres.

And above two degrees, says the report, the risks increase "very 
substantially".

This could involve "potentially large numbers of extinctions or even ecosystem 
collapses".

Such a rise could also lead to "major increases in hunger and water shortage risks as well as socio-economic damages, 
particularly in developing countries".

'Without delight'

The report asked scientists to calculate which greenhouse gas concentrations in the atmosphere would be enough to cause 
these "dangerous" temperature increases.

        
No country is going to turn off a power station which is providing much-desired energy for its population to tackle this 
problem
Sir David King

Currently, the atmosphere contains about 380 parts per million (ppm) of carbon dioxide, the principal greenhouse gas, 
compared to levels before the industrial revolution of about 275ppm.

To have a good chance of achieving the EU's two-degree target, levels should be stabilised at 450ppm or below, the 
report concludes.

But, speaking on Today, the UK government's chief scientific adviser, Sir 
David King, said that was unlikely to happen.

"We're going to be at 400 ppm in 10 years' time, I predict that without any 
delight in saying it," he said.

"But no country is going to turn off a power station which is providing much-desired energy for its population to tackle 
this problem - we have to accept that.

"To aim for 450 (ppm) would, I am afraid, seem unfeasible."

        

But Miles Allen, a lecturer on atmospheric physics at Oxford University, said assessing a "safe level" of carbon dioxide 
in the atmosphere was "a bit like asking a doctor what's a safe number of cigarettes to smoke per day".

"There isn't one but at the same time people do smoke and live until they're 
90," he told Today.

"It's one of those difficult areas where we're talking about changing degrees of risk rather than a very definite number 
after which we can say with absolute certainty that certain things will happen."

Technological hope

On the other question asked at the 2005 conference - what are the options for avoiding dangerous concentrations in 
greenhouse gas emissions - the report says that technological options do exist.

They include ways to increase energy efficiency, renewable energy sources, and 
"clean coal" processes.

Financial mechanisms which can increase their uptake, such as emissions 
trading, are also in existence.

But the report concludes that the "biggest problems" in implementing those options will be how quickly they are adopted, 
and by what proportion of governments.