World's top climate scientists confess: Global warming is just QUARTER what we thought - and computers got the effects of greenhouse gases wrong

Leaked report reveals the world has warmed at quarter the rate claimed by IPCC in 2007



Scientists accept their computers may have exaggerated



The Intergovernmental Panel on Climate Change has changed its story after issuing stern warnings about climate change for years

A leaked copy of the world’s most authoritative climate study reveals scientific forecasts of imminent doom were drastically wrong.

The Mail on Sunday has obtained the final draft of a report to be published later this month by the UN Intergovernmental Panel on Climate Change (IPCC), the ultimate watchdog whose massive, six-yearly ‘assessments’ are accepted by environmentalists, politicians and experts as the gospel of climate science.

They are cited worldwide to justify swingeing fossil fuel taxes and subsidies for ‘renewable’ energy.

Yet the leaked report makes the extraordinary concession that over the past 15 years, recorded world temperatures have increased at only a quarter of the rate of IPCC claimed when it published its last assessment in 2007.

Back then, it said observed warming over the 15 years from 1990-2005 had taken place at a rate of 0.2C per decade, and it predicted this would continue for the following 20 years, on the basis of forecasts made by computer climate models.

But the new report says the observed warming over the more recent 15 years to 2012 was just 0.05C per decade - below almost all computer predictions.



The 31-page ‘summary for policymakers’ is based on a more technical 2,000-page analysis which will be issued at the same time. It also surprisingly reveals: IPCC scientists accept their forecast computers may have exaggerated the effect of increased carbon emissions on world temperatures – and not taken enough notice of natural variability.

They recognise the global warming ‘pause’ first reported by The Mail on Sunday last year is real – and concede that their computer models did not predict it. But they cannot explain why world average temperatures have not shown any statistically significant increase since 1997.

lThey admit large parts of the world were as warm as they are now for decades at a time between 950 and 1250 AD – centuries before the Industrial Revolution, and when the population and CO2 levels were both much lower.

lThe IPCC admits that while computer models forecast a decline in Antarctic sea ice, it has actually grown to a new record high. Again, the IPCC cannot say why.

lA forecast in the 2007 report that hurricanes would become more intense has simply been dropped, without mention.



This year has been one of the quietest hurricane seasons in history and the US is currently enjoying its longest-ever period – almost eight years – without a single hurricane of Category 3 or above making landfall.

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’.

Despite the many scientific uncertainties disclosed by the leaked report, it nonetheless draws familiar, apocalyptic conclusions – insisting that the IPCC is more confident than ever that global warming is mainly humans’ fault.

It says the world will continue to warm catastrophically unless there is drastic action to curb greenhouse gases – with big rises in sea level, floods, droughts and the disappearance of the Arctic icecap.

Last night Professor Judith Curry, head of climate science at Georgia Institute of Technology in Atlanta, said the leaked summary showed that ‘the science is clearly not settled, and is in a state of flux’.

She said it therefore made no sense that the IPCC was claiming that its confidence in its forecasts and conclusions has increased.

For example, in the new report, the IPCC says it is ‘extremely likely’ – 95 per cent certain – that human influence caused more than half the temperature rises from 1951 to 2010, up from ‘very confident’ – 90 per cent certain – in 2007.

Prof Curry said: ‘This is incomprehensible to me’ – adding that the IPCC projections are ‘overconfident’, especially given the report’s admitted areas of doubt.

Head of climate science at Georgia Institute of Technology in Atlanta, said the leaked summary showed that 'the science is clearly not settled, and is in a state of flux'

Starting a week tomorrow, about 40 of the 250 authors who contributed to the report – and supposedly produced a definitive scientific consensus – will hold a four-day meeting in Stockholm, together with representatives of most of the 195 governments that fund the IPCC, established in 1998 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP).

The governments have tabled 1,800 questions and are demanding major revisions, starting with the failure to account for the pause.

Prof Curry said she hoped that the ‘inconsistencies will be pointed out’ at the meeting, adding: ‘The consensus-seeking process used by the IPCC creates and amplifies biases in the science. It should be abandoned in favour of a more traditional review that presents arguments for and against – which would better support scientific progress, and be more useful for policy makers.’ Others agree that the unwieldy and expensive IPCC assessment process has now run its course.

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.’

Climate change sceptics are more outspoken. Dr Benny Peiser, of the Global Warming Policy Foundation, described the leaked report as a ‘staggering concoction of confusion, speculation and sheer ignorance’.

As for the pause, he said ‘it would appear that the IPCC is running out of answers . . . to explain why there is a widening gap between predictions and reality’.

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.

As a result of the warming pause, several recent peer-reviewed scientific studies have suggested that the true figure for the sensitivity is much lower than anyone – the IPCC included – previously thought: probably less than 2C.

Last night IPCC communications chief Jonathan Lynn refused to comment, saying the leaked report was ‘still a work in progress’.



MET OFFICE'S COMPUTER 'FUNDAMENTALLY FLAWED' SAYS NEW ANALYSIS

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. Mr Lewis concludes that the Met Office modelling is ‘fundamentally unsatisfactory, because it effectively rules out from the start the possibility that both aerosol forcing and climate sensitivity are modest’. Yet this, he writes, ‘is the combination that recent observations support’. The Met Office said it would examine the paper and respond in due course.



‘Children of MoS reporter should murder him’: vile abuse on Guardian site

The Mail on Sunday’s report last week that Arctic ice has had a massive rebound this year from its 2012 record low was followed up around the world – and recorded 174,200 Facebook ‘shares’, by some distance a record for an article on the MailOnline website.

But the article and its author also became the object of extraordinarily vitriolic attacks from climate commentators who refuse to accept any evidence that may unsettle their view of the science.



A Guardian website article claimed our report was ‘delusional’ because it ignored what it called an ‘Arctic death spiral’ caused by global warming.

Beneath this, some readers who made comments had their posts removed by the site moderator, because they ‘didn’t abide by our community standards’.



But among those that still remain on the site is one which likens the work of David Rose – who is Jewish – to Adolf Hitler’s anti-Semitic rant Mein Kampf.

Another suggests it would be reasonable if he were to be murdered by his own children. A comment under the name DavidFTA read: ‘In a few years, self-defence is going to be made a valid defence for parricide [killing one’s own father], so Rose’s children will have this article to present in their defence at the trial.’



Critics of the article entirely ignored its equally accurate statement that there is mounting evidence the Arctic sea ice retreat has in the past been cyclical: there were huge melts in the 1920s, followed by later advances.



David Rose¿s article in the Mail on Sunday last week attracted world wide interest

Some scientists believe that this may happen again, and may already be under way – delaying the date when the ice cap might vanish by decades or even centuries.



Another assault was mounted by Bob Ward, spokesman for the Grantham Institute for Climate Change at the London School of Economics.

Mr Ward tweeted that the article was ‘error-strewn’.

The eminent US expert Professor Judith Curry, who unlike Mr Ward is a climate scientist with a long list of peer-reviewed publications to her name, disagreed.

On her blog Climate Etc she defended The Mail on Sunday, saying the article contained ‘good material’, and issued a tweet which challenged Mr Ward to say what these ‘errors’ were.

He has yet to reply.

'A REFLECTION OF EVIDENCE FROM NEW STUDIES'... THE IPCC CHANGES ITS STORY

Power house: The IPCC'S Headquarters in Geneva, Switzerland What they say: ‘The rate of warming over the past 15 years [at 0.05C per decade] is smaller than the trend since 1951.'

What this means: In their last hugely influential report in 2007, the IPCC claimed the world had warmed at a rate of 0.2C per decade 1990-2005, and that this would continue for the following 20 years.

The unexpected 'pause' means that at just 0.05C per decade, the rate 1998-2012 is less than half the long-term trend since 1951, 0.12C per decade, and just a quarter of the 2007-2027 prediction.

Some scientists - such as Oxford's Myles Allen - argue that it is misleading to focus on this 'linear trend', and that one should only compare averages taken from decade-long blocks.

What they say: ‘Surface temperature reconstructions show multi-decadal intervals during the Medieval Climate Anomaly (950-1250) that were in some regions as warm as in the late 20th Century.’ What this means: As recently as October 2012, in an earlier draft of this report, the IPCC was adamant that the world is warmer than at any time for at least 1,300 years. Their new inclusion of the ‘Medieval Warm Period’ – long before the Industrial Revolution and its associated fossil fuel burning – is a concession that its earlier statement is highly questionable. What they say: ‘Models do not generally reproduce the observed reduction in surface warming trend over the last 10 – 15 years.’ What this means: The ‘models’ are computer forecasts, which the IPCC admits failed to ‘see... a reduction in the warming trend’. In fact, there has been no statistically significant warming at all for almost 17 years – as first reported by this newspaper last October, when the Met Office tried to deny this ‘pause’ existed.In its 2012 draft, the IPCC didn’t mention it either. Now it not only accepts it is real, it admits that its climate models totally failed to predict it. What they say: ‘There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing greenhouse-gas forcing.’ What this means: The IPCC knows the pause is real, but has no idea what is causing it. It could be natural climate variability, the sun, volcanoes – and crucially, that the computers have been allowed to give too much weight to the effect carbon dioxide emissions (greenhouse gases) have on temperature change. What they say: ‘Climate models now include more cloud and aerosol processes, but there remains low confidence in the representation and quantification of these processes in models.’ What this means: Its models don’t accurately forecast the impact of fundamental aspects of the atmosphere – clouds, smoke and dust. What they say: ‘Most models simulate a small decreasing trend in Antarctic sea ice extent, in contrast to the small increasing trend in observations... There is low confidence in the scientific understanding of the small observed increase in Antarctic sea ice extent.’ What this means: The models said Antarctic ice would decrease. It’s actually increased, and the IPCC doesn’t know why.

What they say: ‘ECS is likely in the range 1.5C to 4.5C... The lower limit of the assessed likely range is thus less than the 2C in the [2007 report], reflecting the evidence from new studies.’ What this means: ECS – ‘equilibrium climate sensitivity’ – is an estimate of how much the world will warm every time carbon dioxide levels double. A high value means we’re heading for disaster. Many recent studies say that previous IPCC claims, derived from the computer models, have been way too high. It looks as if they’re starting to take notice, and so are scaling down their estimate for the first time.

Clarification

An original version of this article sought to make the fairest updated comparison with the 0.2C warming rate stated by the IPCC in 2007.

It drew on the following sentence in the draft 2013 summary: ‘The rate of warming over the past 15 years… of 0.05C per decade is smaller than the trend since 1951, 0.12C per decade.’ This would represent a reduction in the rate of warming by a little under one half.

But critics argued that the 0.2C warming rate in the 2007 report relates only to the previous 15 years whereas the 0.12C figure in the forthcoming report relates to the half-century since 1951. They pointed out that the equivalent figure in the 2007 report was 0.13C.

This amended article compares the 0.05C per decade observed in the past 15 years with the 0.2C per decade observed in the period 1990-2005 and with the prediction that this rate per decade would continue for a further 20 years.