Carbon emissions are at their highest ever levels, stoking fears of a global temperature rise over the "dangerous" two degrees Celsius threshold, according to data cited by the Guardian newspaper.
Unpublished estimates from the International Energy Agency revealed that the world economy's return to growth in 2010 coincided with a 1.6 gigatonne rise in carbon dioxide emissions, the highest ever recorded jump.
"This is the worst news on emission," IEA chief economist Faith Birol told the British newspaper.
"It is becoming extremely challenging to remain below two degrees", he added. "The prospect is getting bleaker. That is what the numbers say."
Scientists believe that a temperature rise of more than two degrees Celsius would represent "dangerous climate change".
The IEA has warned that annual energy-related emissions should be no higher than 32Gt by 2020.
The latest figures estimate that 30.6Gt of carbon dioxide were emitted in 2010.
Nicholas Stern of the London School of Economics, the author of an influential report into the economics of climate change, predicted dire consequences unless emissions were reined in.
"These figures indicate that (emissions) are now close to being back on a 'business as usual' path," he told the paper.
According to... projections, such a path ... would mean around a 50% chance of a rise in global average temperature of more than 4C by 2100," he added.
"Such warming would disrupt the lives and livelihoods of hundreds of millions of people across the planet, leading to widespread mass migration and conflict," he added.
Around three-quarters of the rise was attributed to emerging economies.
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