The world has warmed 0.05 degrees Celsius (0.09 degrees Fahrenheit) per decade over the past 15 years, a fraction of the 0.2ºC (0.36ºF) per decade rate confidently predicted by the U.N. six years ago, according to a leaked copy of the foremost climate report in the world.

That report, which is updated every six years by the U.N.’s Intergovernmental Panel on Climate Change (IPCC), is called the Assessment Report, and the fifth version (AR5) will be released Sept. 27. has obtained a leaked copy of the first part of AR5 -- and data in it appears to acknowledge that the world’s temperatures haven’t skyrocketed as many had feared.

“The rate of warming over the past 15 years (0.05°C per decade) is smaller than the trend since 1951 (0.12°C per decade),” the draft report states.

2007's AR4 observed a similar warming trend (0.13°C per decade) since 1951, yet the report incorrectly asserted that global temperatures would soar by 0.2°C per decade through 2037 -- and several climate reporters took the failed prediction to mean alarm about global warming had been raised decades before the problem hit crisis levels.

'The idea of producing a document of near-biblical infallibility is a misrepresentation of how science works.'

- Professor Myles Allen, the director of Oxford University’s Climate Research Network

“Scientific forecasts of imminent doom were drastically wrong,” wrote the Daily Mail’s David Rose.

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Jonathan Lynn, a spokesman for the IPCC group that compiles the report, said Rose misinterpreted it.

"As usual, David Rose's article is wrong," Lynn told But the 2007 report did in fact predict greater warming than it had been measuring for decades -- the higher, 0.2ºC value.

One of the report’s own authors, Professor Myles Allen, the director of Oxford University’s Climate Research Network, said this should be the last such assessment.

"The idea of producing a document of near-biblical infallibility is a misrepresentation of how science works, and we need to look very carefully about what the IPCC does in future," Allen said.

Don Wuebbles, coordinating lead author of the forthcoming report and a professor of Atmospheric Science at the University of Illinois, disagreed with how the Mail characterized the study.

“There’s been a lot of playing around with this by the denialist community in the last few weeks,” he told Many people seek to spin the report and end up confusing short term planetary responses with long term ones, he noted.

“People tend to look at short term cycles and say the models don’t match. To me that’s not surprising,” Wuebbles told

The problem lies in the hotly debated "pause” in global warming over the last decade or more, which many have taken as an indication that a warming cycle has ended. Wuebbles confirmed that the upcoming report would address the pause, something the group is still struggling to mesh with climate models.

“We discuss the hiatus and issues about that in IPCC … but we still have incomplete information until some of the new studies come out that put the nail in that coffin,” he told, citing current research that still needs to be synthesized into the draft.

Meanwhile the dozens of editors and writers collaborating on the report continue to revise it daily, he said, meaning the leaked copies seen by the Mail and have likely already changed.

“There are definitely going to be wording changes that occur before it is published," he said.

But the leaked report’s conclusion appear to align with a key new study in the journal Nature Climate Change, which revealed that nearly all climate models are dramatically inaccurate.

That report compared 117 climate predictions made in the 1990's to the actual amount of warming. Out of 117 predictions, the study’s author told, 3 were roughly accurate and 114 overestimated the amount of warming. On average, the predictions forecasted two times more global warming than actually occurred.

And it was also confirmed by Matt Ridley, a member of the British House of Lords and a fellow of the Academy of Medical Sciences.

“For the first time since these reports started coming out in 1990, the new one dials back the alarm,” Ridley wrote in the Wall Street Journal.

Wuebbles took issue with Ridley’s portrayal of the report as well.

“That was kind of a distorted look at it,” he told “That’s not what’s in the assessment.”

The challenge the group faces is in taking complex science and making it simple for the world to understand. People reading early copies of the report are twisting it to their own purposes, he said.

“It’s leading to a lot of distorted information getting out there.”

Jeremy A. Kaplan is Science and Technology editor at, where he heads up coverage of gadgets, the online world, space travel, nature, the environment, and more. Prior to joining Fox, he was executive editor of PC Magazine, co-host of the Fastest Geek competition, and a founding editor of GoodCleanTech.