Has it happend before?

THE world is spinning toward a catastrophic worst case climate change scenario with temperatures now certain to rise by 6 degrees by the end of the century.

That's the view of a leading international team of scientists who yesterday predicted the change in climate would now certainly have irreversible consequences rendering large parts of the globe inhabitable.

The scenario was first made public by the UN Intergovernmental Panel on Climate Change in 2007 but then it was made only as a worst case scenario.

But according to Professor Corinne Le Quere from the British Antarctic Survey and East Anglia University, that worst case was now all but inevitable.

"We're at the top of the IPCC scenario," she told Nature Geoscience.

Her study - backed by 31 top researchers from seven countries including Australia involved in the Global Carbon Project - found there had been a 29 per cent rise in global CO2 emissions from fossil fuels between 2000 and 2008, with an annual increase of 3 per cent compared with 1 per cent the previous eight years.

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She said there was no doubt carbon dioxide emissions from transport and industry and deforestation were squarely to blame for warming the atmosphere which would be 6 per cent higher around the world including near the poles; the EU had hoped to keep the rise to 2 per cent.

Prof Le Quere said next month's UN climate conference in Copenhagen had to come out with a clear and decisive global policy to stabilize temperatures.

"If the agreement is too weak or the commitments not respected, it is not 2.5 degrees or 3 degrees we will get it's 5 degrees or 6 degrees, that is the path we're on," she said.

Scientists have found there was now significant evidence to show for the first time the Earth's natural ability to absorb man-made carbon dioxide released into the air had failed.

Both the US and China, the world's biggest carbon emitters, have pledged to strike an accord for emission-reduction targets for rich nations.

Warming diagnosis: beyond worst case
ADAM MORTON
November 25, 2009

KEY climate change measures are tracking near or beyond worse-case scenarios predicted just two years ago, according to a science update drawing on more than 200 recently published studies.

Co-authored by 26 climate scientists, The Copenhagen Diagnosis reports that melting of summer Arctic sea ice, loss of the Greenland and Antarctic ice sheets, and projections of the rise in sea levels have accelerated dramatically since 2007.

It finds the statistical global warming trend has continued over the past decade, contradicting assessments by some scientists - including Copenhagen Climate Council chairman Tim Flannery - that there has been a recent cooling.

The review cites NASA data that shows a trend of a 0.19-degree increase over the past decade despite short-term fluctuations due to El Nino, solar variability and volcanic eruptions.

Matthew England, co-director of the University of NSW Climate Change Research Centre, said the world's three leading climate data series showed claims of temperatures cooling were ''patently untrue''.

''These are the data set even the sceptics go to, and they show that the last 10 years has been one of warming even if you start in [the particularly hot] 1998,'' Professor England said.

''Since 2001, every year has been among the top-10 warmest on record. I don't think that is cooling.''

The diagnosis is billed as a supplement to the 2007 report by the UN's Intergovernmental Panel on Climate Change and aimed at influencing debate at next month's Copenhagen climate summit. Most of the scientists behind it are intergovernmental panel authors.

Its major findings include:

■ Greenhouse gas emissions from fossil fuel burning and cement production were nearly 40 per cent higher in 2008 than in 1990.

■ Global air temperature, humidity and rainfall patterns cannot be explained without factoring in greenhouse gas emissions.

■ Satellite and ice measurements show the Greenland and Antarctic ice sheets are increasingly losing mass. Each adds up to 0.7 millimetres a year to sea level rise.

■ The recent rate of summer Arctic see ice melting is unprecedented in at least 2000 years and about 40 per cent greater than average IPCC predictions.

■ Sea-level rise by 2100 is likely to be much greater than the 18-59 centimetres predicted by the UN panel. Failure to cut emissions could lead to a rise of more than a metre. The worse-case scenario is roughly two metres (though unlikely).

■ Localised tipping points, where changes happen abruptly, are possible this century at some sites. But despite talk of ''runaway climate change'', there is no strong evidence that the entire planet is near that threshold.

The report estimates global temperatures could rise by seven degrees by 2100. Emissions would need to peak in the next five to 10 years to limit warming to two degrees.

It comes at a charged time in the climate debate. Emails stolen from a leading climate research centre have prompted claims its scientists tried to massage unfavourable data and destroy scientific material sought under Freedom of Information. Professor England said the scandal was a diversion:

''A few loose email comments by a couple of researchers does not bring down the central science of climate change.''