Copenhagen climate change summit: We have just 10 years to avert catastrophe warns Met Office, as 1,700 scientists defend global warming research
Planet Earth faces a climate change catastrophe unless carbon emissions fall within the next decade, the Met Office has warned.
Emissions must drop over the next ten years to ensure global temperatures rise by just 2C above pre-industrial levels - the critical limit that leading industrial nations have agreed, scientists told the Copenhagen climate change conference.
Even if emissions peak in 2020, there would still be a 50 per cent chance of temperatures rising by more than two degrees, heralding potential global catastrophe, they added.
Climate change: A melting ice sculpture of a polar bear in Copenhagen, where scientists told the climate change conference that carbon emissions must fall within ten years
The warning, in the Met Office's Avoid, study, came as more than 1,700 scientists signed a statement to defend global warming research.
The petition was organised by the Met Office in the wake of the stolen emails row.
The experts became concerned after climate change sceptics seized on material taken from servers at the University of East Anglia's Climatic Research Unit to claim researchers have been manipulating evidence to support a theory of man-made global warming.
The statement signed by the scientists says: 'We, members of the UK science community, have the utmost confidence in the observational evidence for global warming and the scientific basis for concluding that it is due primarily to human activities.'
A Met Office spokesman said John Hirst, its chief executive, and Julia Slingo, its chief scientist, wrote to 70 colleagues on Sunday asking them to sign 'to defend our profession against this unprecedented attack to discredit us and the science of climate change'.
They asked them to forward the petition to colleagues to generate support 'for a simple statement that we... have the utmost confidence in the science base that underpins the evidence for global warming'.
The University of East Anglia has appointed Scottish civil servant and former principal and vice-chancellor of the University of Glasgow, Sir Muir Russell, to head an independent review into the email allegations.
The Avoid study - carried out by the Met Office with several other British scientific groups - found that limiting a global temperature rise to 1.5C was now 'virtually impossible' because of all the greenhouse gases already pumped out.
That goal has been called for by some poor African countries and small island states - areas of the world seen as being most at risk from global warming.
Even if emissions were suddenly reduced to nothing, there would still be a rise of 1.3C because of the existing greenhouse gases in the atmosphere, Avoid has found.
Researchers calculated that if emissions started falling by 4 per cent per year after 2018 that would give a 50 per cent chance of keeping warming below 2C.
But if the peak came just two years later in 2020, the decline would then have to be 5 per cent per year to deliver the same odds.
Vicky Pope, the Met Office's head of climate science, told the BBC: 'If you go to 2025 before peaking, it's virtually impossible to stay under 2C.
'There's no way you'd get a 50 per cent chance of avoiding 1.5C.'
Delegates in Copenhagen heard that ensuring a reasonable chance of keeping the temperature rise under 1.5C would involve 'negative emissions' - or removing CO2 from the air.
If carbon output peaks later than 2020, 'geo-engineering' techniques such as mirrors in space and artificial trees would be needed to hit the 2C target.
More than 190 countries are gathered in Copenhagen for UN climate change talks.
Earlier this week the Met Office said the past decade has been the warmest period in the 160-year record of global surface temperatures.