One of the report’s own authors, Professor Myles Allen, the director of Oxford University’s Climate Research Network, last night said this should be the last IPCC assessment – accusing its cumbersome production process of ‘misrepresenting how science works’.
Prof Allen said: ‘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
The Mail on Sunday has also seen an earlier draft of the report, dated October last year. There are many striking differences between it and the current, ‘final’ version.
The 2012 draft makes no mention of the pause and, far from admitting that the Middle Ages were unusually warm, it states that today’s temperatures are the highest for at least 1,300 years, as it did in 2007. Prof Allen said the change ‘reflects greater uncertainty about what was happening around the last millennium but one’.
A further change in the new version is the first-ever scaling down of a crucial yardstick, the ‘equilibrium climate sensitivity’ – the extent to which the world is meant to warm each time CO2 levels double.
As things stand, the atmosphere is expected to have twice as much CO2 as in pre-industrial times by about 2050. In 2007, the IPCC said the ‘likeliest’ figure was 3C, with up to 4.5C still ‘likely’.
Now it does not give a ‘likeliest’ value and admits it is ‘likely’ it may be as little as 1.5C – so giving the world many more decades to work out how to reduce carbon emissions before temperatures rise to dangerous levels.
The British Met Office has issued ‘erroneous statements and misrepresentations’ about the pause in global warming – and its climate computer model is fundamentally flawed, says a new analysis by a leading independent researcher.
Nic Lewis, a climate scientist and accredited ‘expert reviewer’ for the IPCC, also points out that Met Office’s flagship climate model suggests the world will warm by twice as much in response to CO2 as some other leading institutes, such as Nasa’s climate centre in America.
The Met Office model’s current value for the ‘equilibrium climate sensitivity’ (ECS) – how much hotter the world will get each time CO2 doubles – is 4.6C. This is above the IPCC’s own ‘likely’ range and the 95 per cent certainty’ level established by recent peer-reviewed research.
Lewis’s paper is scathing about the ‘future warming’ document issued by the Met Office in July, which purported to explain why the current 16-year global warming ‘pause’ is unimportant, and does not mean the ECS is lower than previously thought.
Lewis says the document made misleading claims about other scientists’ work – for example, misrepresenting important details of a study by a team that included Lewis and 14 other IPCC experts. The team’s paper, published in the prestigious journal Nature Geoscience in May, said the best estimate of the ECS was 2C or less – well under half the Met Office estimate.
He also gives evidence that another key Met Office model is inherently skewed. The result is that it will always produce high values for CO2-induced warming, no matter how its control knobs are tweaked, because its computation of the cooling effect of smoke and dust pollution – what scientists call ‘aerosol forcing’ – is simply incompatible with the real world.
This has serious implications, because the Met Office’s HadCM3 model is used to determine the Government’s climate projections, which influence policy.
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World's top climate scientists confess: Global warming is just QUARTER what we thought - and computers got the effects of greenhouse gases wrong | Mail Online