IT IS "improbable" global warming will be kept below 4C – double the rise considered safe to avoid climate catastrophe – according to an influential new report.
Internationally, it has long been agreed governments should be aiming to keep a global temperature rise below 2C, to avoid climate change spiralling out of control.
However, a bleak new study by scientists at the Tyndall Centre, a leading organis
ation for climate change research at the University of Manchester, now suggests we should be adjusting our expectations towards far higher rises.
It warns carbon dioxide in the atmosphere will almost certainly stabilise at levels of at least 650 parts per million (ppm), which is roughly equivalent to a four-degree temperature increase.
The authors write: "Given the reluctance, at virtually all levels, to openly engage with the unprecedented scale of both current emissions and their associated growth rates, even an optimistic interpretation of the current framing of climate change implies that stabilisation much below 650ppm is improbable."
The authors say even stabilising levels at 650ppm will require industrialised nations to "begin to make draconian emission reductions within a decade".
They argue "planned economic recession" would be needed to keep climate change at this level, unless a way can be found for economic growth to go hand in hand with unprecedented rates of reductions in carbon emissions.
One of the report authors, Dr Alice Bows, agreed the study is "incredibly worrying". She added: "We are certainly not on track for a two-degree temperature increase at the moment. We are much more on track for a three to four-degree temperature increase and we need to be thinking about what that actually means."
According to the 2006 Stern review on the economics of climate change, a four-degree temperature rise could lead to up to 300 million more people being affected by coastal flooding each year, a 30 to 50 per cent reduction in water availability in Southern Africa, and up to 50 per cent of animal and plant species facing extinction.
Dr Richard Dixon, director of World Wildlife Fund (WWF) Scotland, said an increase of more than two degrees could mean a "tipping point" is reached. "That's when you get to a runaway situation," he said. "The big systems of the world start to go wrong when you get beyond two degrees."
However, he thinks the report is at the "bleak" end of the spectrum and believes there is still reason for optimism, as long as firm targets are set at the United Nations climate change conference in Copenhagen next year.
"Certainly, if there's not a good result at Copenhagen, the two-degree target will look impossible," he said. "There's 18 months of optimism to hold on to. If by Copenhagen it hasn't been addressed then it will look very bleak indeed."
The report, Reframing the Climate Change Challenge in Light of Post-2000 Emission Trends, comes as separate research, due to be published in Nature Geoscience today, will warn that the expected rise in sea levels due to melting Greenland ice has been seriously underestimated.
Scientists argue it could be double or triple what is currently forecast over the next century.
The full article contains 538 words and appears in The Scotsman newspaper.
