Thursday, March 12, 2009

"Global temperatures 'will rise 6C this century'"

For people following this - it looked like the 2007 IPCC conference was being too optimistic /not realistic. (There has since been a lot of "things are worse than expected' comments.) This time - it looks like the conference better reflects the science.

From the

Surging global greenhouse gas emissions mean the world now faces likely temperature rises of up to 5-6C this century, according to the scientist leading the international Climate Congress in Copenhagen this week.

Professor Katharine Richardson, who chaired the scientific steering committee for the conference, said it was now almost impossible for the world to achieve the UN target of preventing global temperature rise exceeding 2C.

"We can forget about the 2C"," said Richardson in an interview. "We are now facing the situation where we have to avoid a 5-6C rise in temperature."

Richardson said her comments were based on sifting through hundreds of science research papers submitted to the congress. Details of the research are being presented to delegates this week and will be used in a report for the UN.

Her comments were not the only bad news to emerge on the first day of the International Scientific Congress on Climate Change (IPCC) in Copenhagen. Other researchers warned that sea levels are now rising 50% faster than suggested by the Intergovernmental Panel on Climate Change in its 2007 report.

It means the world’s oceans could rise by a metre or more over the next century and that low-lying coastal areas will be at risk of inundation with hundreds of millions of people displaced, especially in developing countries.

Some of those attending the Copenhagen meeting have dubbed it “the end of the world conference” because the latest research emerging on climate change is so alarming...

The warnings on temperature rise are linked to the surge in greenhouse gas emissions over the last decade. Currently humanity generates the equivalent of about 50 billion tonnes of CO2 a year through burning fossil fuels, agriculture, deforestation and other processes.

In its last report the IPCC made over-cautious assumptions about how these emissions would rise in future – and concluded it would be possible to prevent a total global temperature rise of more than 2C compared with pre-industrial times.

It has since emerged that these assumptions were misplaced and that emissions have grown at around 3 % a year – about twice as fast as the IPCC’s worst case scenario...

Dr John Church of the Centre for Australian Weather and Climate Research, Hobart, Tasmania, Australia, told the conference, sea level rise by 2100 could be in the range of about one meter, or possibly more.

The warning comes from new research into the behaviour of glaciers and ice sheets, especially in Greenland. It had been thought the main effect of global warming was simply to melt them.

However, the new research shows that as water melts it sinks down to the bedrock under the glaciers and lubricates them, so that their movement to the sea accelerates sharply.

This has turned out to be a much more powerful effect than simple melting and means the IPCC, whose 2007 report projected a sea level rise of 18 - 59 cm by 2100, must once again revise its earlier findings...

The point of the Copenhagen meeting is to draw together all the latest science on climate change in preparation for the UN negotiations planned for this December at which politicians will try to draw up a replacement for the Kyoto treaty on reducing greenhouse gases, which expires in 2012.

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