'100 months' to stop overheating

Ian Sample, science correspondent
The Guardian,
Friday August 1 2008

Rising greenhouse gas emissions could pass a critical tipping point and trigger runaway global warming within the next 100 months, according to a report today.
The estimate from the New Economics Foundation is based on when emissions will reach such high levels that it "is no longer likely" the world will be able to avoid a 2C rise in average temperatures. "We know climate change is a huge problem, but there's a missing ingredient of urgency," said Andrew Simms, policy director at the foundation.
According to the UN's experts, greenhouse gas levels in the atmosphere, which are at around 430 parts per million, would have to be stabilised at 450 ppm to avoid a rise of more than 2C.
Simms and Victoria Johnson made a conservative estimate of future emissions based on six greenhouse gases and other pollutants, such as aerosols, which have a cooling effect. They predict that 100 months from today emissions will rise above the critical 450ppm threshold.
According to the government's 2006 report on climate change by Nicholas Stern, a 2C rise could release vast quantities of carbon stored in soils and permafrost, see 15%-40% of land species threatened with extinction, and up to 4 billion people experiencing water shortages.