Tag Archives: AGW

AGW: It’s Never Been About Climate

19 Nov

35506_bear_polar_bear_facepalm

From Democracy Now (oh dear!):

Organizers of the U.N. climate talks in Warsaw, Poland, are facing criticism for accepting corporate sponsorships from major car manufacturers, oil companies, steel manufacturers and coal firms. Meanwhile, the Polish Ministry of Economy has teamed up with the World Coal Association to put on a parallel “International Coal & Climate Summit,” also in Warsaw.

At Least He’s Not A Hypocrite … IF He Goes Through With It

3 Oct

Actions speak louder than words.

As with climate change itself, I am perfectly content to wait and see whether 32 years-young Eric actually goes through with his twin commitments, before drawing any conclusions about his sincerity.

From Investor’s Business Daily:

Crying Like A Schoolgirl Over Global Warming Report

Hysteria: A weeping meteorologist says he’ll forgo jet travel and having children because he’s upset by last week’s climate change report. He will likely be the object of much mockery. But might he also be a victim?

Eric Holthaus appears to be a publicity hound crying out for attention. His tweet explaining how he broke down in tears to his wife upon hearing that the United Nations’ Intergovernmental Panel on Climate Change say it’s 95% certain man is warming Earth is surely self-serving.

So, too, is his claim that on Friday he was boarding “the last flight I ever take” because flying is “not worth the climate.”

The former Wall Street Journal weather writer also pledged to have “no children” and was “thinking of a vasectomy” to help him keep his promise.

It’s OK to laugh at Holthaus. Grown men reacting like schoolgirls should be hooted at with great pleasure.

But maybe it’s not all his fault.

The global warming alarmists have created a climate of madness. Their incessant warnings of worldwide disaster and unspeakable human suffering due to man-made warming have sent some people into a frenzy.

Almost five years ago we wrote on these pages about climate change delusion. The first case diagnosed was in a 17-year-old Australian who refused to drink water because he thought it would cause millions to die from the drought-effects of global warming. He was eventually hospitalized in a psychiatric unit, having been depressed for months before being committed.

At that time, we also mentioned that the psychiatrist in charge of that unit told the Boston Globe that he “has now seen several more patients with psychosis or anxiety disorders focused on climate change.”

There were also stories of children “having nightmares about global-warming-related natural disasters” booking appointments with doctors.

We reported, as well, about the American Psychological Association’s effort to condition the public to believe that humans are causing an environmental crisis, an objective it was confident it could achieve because it knows “how to change behavior and attitudes.”

Is Holthaus a victim of an attempt to whip up hysteria over global warming? Or is he part of the campaign?

Whatever the truth, we now live in a world where it’s fine for a grown man to cry over a modern fable like a child frightened by tales of witches and ghosts.

UPDATE:

Some think he’s not really committed …

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Nobel Prize-Winning Scientist: “We NEVER Are Right. We Can Only Be Sure We’re Wrong.”

29 Sep

Nobel prize winning physicist Richard Feynman is famous for many things. Among them being this statement:

“Science is the belief in the ignorance of experts.”

The following video shows the typically engaging Feynman giving a simple lecture on the scientific method.

Believers in the claim that “the science is settled” regarding alleged “dangerous”, man-made global warming, would do well to listen … very carefully:

Danke Schön Climate Change

25 Sep

I loved Ferris Bueller’s Day Off. This version of ‘Danke Schön’ is much better:

The IPCC’s Fifth Assessment Report is due to be released on September 30th.

Alas, once they start laughing at you, you’re through.

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OECD: Australia Needs $76 Carbon Price To Meet Emissions Target

25 Sep

Holy Man Jam, Boulder, CO  Aug. 1970

From The Australian:

MYSTERIOUSLY, once the election was over, an OECD report with a Treasury official’s input emerged indicating the carbon tax would need to be 10 times the EU rate and twice the $38-per-tonne level posited by Treasury to allow Australia to meet its 5 per cent carbon reduction goal…

The OECD report indicates that unless the developing world also implemented a carbon tax, Australia would see considerable de-industrialisation, moderated only by a retreat into an illegal protectionist regime. And the competitive pressures would further intensify if, as appears likely, Japan, the US and other OECD countries also reject a carbon tax.

This is contrary to the official Treasury line that we need a price on carbon now, that the longer we wait the more painful the transition and that the costs will be trivial. Treasury secretary Martin Parkinson would have known of the report’s findings months ago.

And there we have it.

Treasury knew full well what the true ramifications of our political leaders’ commitment to “emissions reduction” would be. They just weren’t willing to tell us.

Unless the rest of the developing world (China, India, etc) follows our the 2010 Green-Labor alliance’s lead in implementing a carbon tax — which they aren’t — then in trying to meet the 5% emissions reduction target, Australia faces “considerable de-industrialisation”.

The devastating effects of which could only be moderated by … wait for it … protectionist policies.

Which are “illegal”; a reneging on “free trade” agreements, designed by international bankers and multinational monoliths, and happily signed up to by our former leaders, on both “sides”.

Protecting the interests of your own nation’s people is a really terrible and evil thing … according to the “free trade” globalists.

Being “open for business”, and willing to further expose your nation’s people to the predations of that 0.01% who wish to own (thus, rule) the whole world through debt … that is what makes you a “leader” worthy of international acclaim.

IPCC Final Draft Admits Models Have Failed

21 Sep

Doomed-To-Repeat-History

Cross-posted from The Australian (my bold and underline added):

Consensus distorts the climate picture

IN February 2007, publication of the Intergovernmental Panel on Climate Change’s Fourth Assessment Report (AR4) was received with international acclaim.

The vaunted IPCC process — multitudes of experts from more than 100 countries examining thousands of refereed journal publications, with hundreds of expert reviewers, across a period of four years — elevated the authority of the IPCC report to near biblical heights. Journalists jumped on board and even the oil and energy companies neared capitulation.

The veneration culminated with the Nobel Peace Prize, which the IPCC was awarded jointly with former US vice-president Al Gore. At the time, I joined the consensus in supporting this document as authoritative; I was convinced by the rigours of the process. Although I didn’t agree with some statements in the document and had nagging concerns about the treatment of uncertainty, I bought into the meme of: “Don’t trust what one scientist says; trust the consensus-building process of the IPCC experts.”

[TBI: Clearly then, humankind — and science in particular — has learned nothing from history, and the examples of Galileo, Copernicus, and Nicolas Steno.]

Six-and-a-half years later, nominally a week before the release of the IPCC Fifth Assessment Report (AR5), substantial criticisms are being made of leaked versions of the report as well as of the IPCC process. IPCC insiders are bemoaning their loss of scientific and political influence. What happened to precipitate this change?

The IPCC was seriously tarnished by the unauthorised release of emails from the University of East Anglia in November 2009 that became known as the Climategate affair. These emails revealed the “sausage-making” involved in the IPCC’s consensus-building process, including denial of data access to individuals who wanted to audit its data processing and scientific results, interference in the peer-review process to minimise the influence of sceptical criticisms and manipulation of the media.

Climategate was soon followed by the identification of an egregious error involving the melting of Himalayan glaciers. These revelations were made much worse by the response of the IPCC to these issues. Then came concerns about the behaviour of the IPCC’s chairman Rajendra Pachauri and investigations of the infiltration of green advocacy groups into the IPCC. All of this was occurring against a background of explicit advocacy and activism by IPCC leaders related to carbon dioxide mitigation policies.

[TBI: In other words, publicly barracking for the financial sector’s “market-based” “carbon pricing” “solutions” — see The Financialization of Nature.]

Although the scientists and institutions involved in Climategate were cleared of charges of scientific misconduct, the scientists and the IPCC did not seem to understand the cumulative impact of these events on the loss of trust in climate scientists and the IPCC process.

The IPCC’s consensus-building process relies heavily on expert judgment; if the public and the policymakers no longer trust these particular experts, then we can expect a very different dynamic to be in play with regards to the reception of the AR5 relative to the release of the AR4 in 2007.

THERE is another, more vexing dilemma facing the IPCC, however. Since the publication of the AR4, nature has thrown the IPCC a curveball: there has been no significant increase in global average surface temperature for the past 15-plus years. This has been referred to as a pause or hiatus in global warming.

Almost all climate scientists agree on the physics of the infrared emission of the CO2 molecule and understand that if all other things remain equal, more CO2 in the atmosphere will have a warming effect on the planet. Further, almost all agree that the planet has warmed across the past century and that humans have had some impact on the climate.

But understanding the causes of recent climate change and predicting future change is far from a straightforward endeavour.

The heart of the debate surrounding the IPCC’s AR5 is summarised by the graphic on this page that compares climate model projections of global average surface temperature anomalies against observations.

The above graphic is Figure 1.4 from Chapter 1 of a draft of the Fifth Assessment Report from the Intergovernmental Panel on Climate Change. The initials at the top represent the First Assessment Report (FAR) in 1990, the Second (SAR) in 1995. Shaded banks show range of predictions from each of the four climate models used for all four reports since 1990. That last report, AR4, was issued in 2007. Model runs after 1992 were tuned to track temporary cooling due to the 1991 Mount Pinatubo eruption in The Philippines. The black squares, show with uncertainty bars, measure the observed average surface temperatures over the same interval. The range of model runs is syndicated by the vertical bars. The light grey area above and below is not part of the model prediction range. The final version of the new IPCC report, AR5, will be issued later this month.

This diagram is Figure 1.4 from the first chapter of an AR5 draft. FAR denotes the First Assessment Report (1990), SAR the second (1995) and TAR the third (2001), which was followed by the AR4 (2007). It is seen that climate models have significantly over-predicted the warming effect of CO2 since 1990, a period during which CO2 concentrations increased from 335 parts per million to more than 400ppm.

The most recent climate model simulations used in the AR5 indicate that the warming stagnation since 1998 is no longer consistent with model projections even at the 2 per cent confidence level. Based on early drafts of the AR5, the IPCC seemed prepared to dismiss the pause as irrelevant noise associated with natural variability. Apparently the IPCC has been under pressure from reviewers and its policymaker constituency to address the pause specifically.

Here is the relevant text from the leaked final draft of the AR5 summary for policymakers:

“Models do not generally reproduce the observed reduction in surface warming trend over the last 10-15 years.

“The observed reduction in warming trend over the period 1998-2012 as compared to the period 1951-2012 is due in roughly equal measure to a cooling contribution from internal variability and a reduced trend in radiative forcing (medium confidence).

“The reduced trend in radiative forcing is primarily due to volcanic eruptions and the downward phase of the current solar cycle. However, there is low confidence in quantifying the role of changes in radiative forcing in causing this reduced warming trend. 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.”

The IPCC acknowledges the pause and admits climate models do not reproduce the pause. I infer from these statements that the IPCC has failed to convincingly explain the pause in terms of external radiative forcing from greenhouse gases, aerosols, solar or volcanic forcing; this leaves natural internal variability as the predominant candidate to explain the pause.

Natural internal variability is associated with chaotic interactions between the atmosphere and ocean. The most familiar mode of natural internal variability is El Nino/La Nina. On longer multi-decadal time scales, there is a network of atmospheric and oceanic circulation regimes, including the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation.

The IPCC refers to this as “unpredictable climate variability” in its statement above.

My chain of reasoning leads me to conclude that the IPCC’s estimates of the sensitivity of climate to greenhouse gas forcing are too high, raising serious questions about the confidence we can place in the IPCC’s attribution of warming in the last quarter of the 20th century primarily to greenhouse gases, and also its projections of future warming. If the IPCC attributes the pause to natural internal variability, then this prompts the question as to what extent the warming between 1975 and 2000 can also be explained by natural internal variability.

Nevertheless, the IPCC concludes in the final AR5 draft of the summary for policymakers: “There is very high confidence that climate models reproduce the observed large-scale patterns and multi-decadal trends in surface temperature, especially since the mid-20th century.

“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951-2010.

“Continued emissions of greenhouse gases would cause further warming. Emissions at or above current rates would induce changes in all components in the climate system, some of which would very likely be unprecedented in hundreds to thousands of years.”

WHY is my reasoning about the implications of the pause, in terms of attribution of the late 20th-century warming and implications for future warming, so different from the conclusions drawn by the IPCC? The disagreement arises from different assessments of the value and importance of particular classes of evidence as well as disagreement about the appropriate logical framework for linking and assessing the evidence. My reasoning is weighted heavily in favour of observational evidence and understanding of natural internal variability of the climate system, whereas the IPCC’s reasoning is weighted heavily in favour of climate model simulations and external forcing of climate change.

I do not expect my interpretation and analysis to be given credence above the IPCC consensus. Rather, I am arguing that the complexity of the problem, acknowledged uncertainties and suspected areas of ignorance indicate several different plausible interpretations of the evidence. Hence ascribing a high confidence level to either of these interpretations is not justified by the available evidence and our present understanding.

How to reason about uncertainties in the complex climate system and its computer simulations is neither simple nor obvious. Biases can abound when reasoning and making judgments about such a complex system, through excessive reliance on a particular piece of evidence, the presence of cognitive biases in heuristics, failure to account for indeterminacy and ignorance, and logical fallacies and errors including circular reasoning.

The politicisation of climate science is another source of bias, including explicit policy advocacy by some IPCC scientists. Further, the consensus-building process can be a source of bias. A strongly held prior belief can skew the total evidence that is available subsequently in a direction that is favourable to itself. The consensus-building process has been found to act generally in the direction of understating the uncertainty associated with a given outcome. Group decisions can be dominated by a single confident member.

Once the IPCC’s consensus claim was made, scientists involved in the IPCC process had reasons to consider the possible effect of their subsequent statements on their ability to defend the consensus claim, and the impact of their statements on policymaking.

The climate community has worked for more than 20 years to establish a scientific consensus on anthropogenic climate change. The IPCC consensus-building process played a useful role in the early synthesis of the scientific knowledge. However, the ongoing scientific consensus-seeking process has had the unintended consequence of oversimplifying the problem and its solution and hyper-politicising both, introducing biases into the science and related decision-making processes.

SCIENTISTS do not need to be consensual to be authoritative. Authority rests in the credibility of the arguments, which must include explicit reflection on uncertainties, ambiguities and areas of ignorance, and more openness for dissent. The role of scientists should not be to develop political will to act by hiding or simplifying the uncertainties, explicitly or implicitly, behind a negotiated consensus. I have recommended that the scientific consensus-seeking process be abandoned in favour of a more traditional review that presents arguments for and against, discusses the uncertainties, and speculates on the known and unknown unknowns. I think such a process would support scientific progress far better and be more useful for policymakers.

The growing implications of the messy wickedness of the climate-change problem are becoming increasingly apparent, highlighting the inadequacies of the “consensus to power” approach for decision-making on such complex issues.

Let’s abandon the scientific consensus-seeking approach in favour of open debate and discussion of a broad range of policy options that stimulate local and regional solutions to the multifaceted and interrelated issues surrounding climate change.

Judith Curry is a professor and chair of the school of earth and atmospheric sciences at the Georgia Institute of Technology in the US, and president of Climate Forecast Applications Network. She is proprietor of the blog Climate Etc.

judithcurry.com

Climate Scientists Told To “Cover Up” Warming Pause

20 Sep

From the Daily Mail (UK):

Scientists working on the most authoritative study on climate change were urged to cover up the fact that the world’s temperature hasn’t risen for the last 15 years, it is claimed.

A leaked copy of a United Nations report, compiled by hundreds of scientists, shows politicians in Belgium, Germany, Hungary and the United States raised concerns about the final draft.

Published next week, it is expected to address the fact that 1998 was the hottest year on record and world temperatures have not yet exceeded it, which scientists have so far struggled to explain.

The report is the result of six years’ work by UN’s Intergovernmental Panel on Climate Change (IPCC), which is seen as the world authority on the extent of climate change and what is causing it – on which governments including Britain’s base their green policies.

But leaked documents seen by the Associated Press, yesterday revealed deep concerns among politicians about a lack of global warming over the past few years…

The latest report, which runs to 2,000 pages, will be shown to representatives from all 195 governments next week at a meeting in Stockholm, who can discuss alterations they want to make.

But since it was issued to governments in June, they have raised hundreds of objections about the 20-page summary for policymakers, which sums up the findings of the scientists.

What it says will inform renewable energy policies and how much consumers and businesses will pay for them.

The report is expected to say the rate of warming between 1998 and 2012 was about half of the average rate since 1951 – and put this down to natural variations such as the El Nino and La Nina ocean cycles and the cooling effects of volcanoes…

The key to understanding the truth about the role played by the IPCC, is right there in the sentence bolded above.

It’s all about money, and propaganda.

The rationalisation of the financialisation of nature:

https://vimeo.com/43398910

IPCC Forecasts Of Climate Doom Drastically Wrong

16 Sep

5e8

More on the unravelling of the Great Global Warming Swindle.

From the Mail on Sunday (UK):

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 the world has been warming at only just over half the rate claimed by the IPCC in its last assessment, published in 2007.

Back then, it said that the planet was warming at a rate of 0.2C every decade – a figure it claimed was in line with the forecasts made by computer climate models.

But the new report says the true figure since 1951 has been only 0.12C per decade – a rate far below even the lowest computer prediction.

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.

They 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.

The 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…

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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…

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.

We Got It Wrong On Global Warming: IPCC

16 Sep

dunce

From the Environment Editor at The Australian:

THE Intergovernmental Panel on Climate Change’s latest assessment reportedly admits its computer drastically overestimated rising temperatures, and over the past 60 years the world has in fact been warming at half the rate claimed in the previous IPCC report in 2007.

More importantly, according to reports in British and US media, the draft report appears to suggest global temperatures were less sensitive to rising levels of atmospheric carbon dioxide than was previously thought.

The 2007 assessment report said the planet was warming at a rate of 0.2C every decade, but according to Britain’s The Daily Mail the draft update report says the true figure since 1951 has been 0.12C.

Last week, the IPCC was forced to deny it was locked in crisis talks as reports intensified that scientists were preparing to revise down the speed at which climate change is happening and its likely impact.

Professor Judith Curry, head of climate science at the Georgia Institute of Technology in Atlanta, told The Daily Mail the leaked summary showed “the science is clearly not settled, and is in a state of flux”.

The Wall Street Journal said the updated report, due out on September 27, would show “the temperature rise we can expect as a result of manmade emissions of carbon dioxide is lower than the IPCC thought in 2007”.

The WSJ report said the change was small but “it is significant because it points to the very real possibility that, over the next several generations, the overall effect of climate change will be positive for humankind and the planet”.

After several leaks and reports on how climate scientists would deal with a slowdown in the rate of average global surface temperatures over the past decade, the IPCC was last week forced to deny it had called for crisis talks.

“Contrary to the articles the IPCC is not holding any crisis meeting,” it said in a statement.

The IPCC said more than 1800 comments had been received on the final draft of the “summary for policymakers” to be considered at a meeting in Stockholm before the release of the final report. It did not comment on the latest report, which said scientists accepted their forecast computers may have exaggerated the effect of increased carbon emissions on world temperatures and not taken enough notice of natural variability.

According to The Daily Mail, the draft report recognised the global warming “pause”, with average temperatures not showing any statistically significant increase since 1997.

Scientists admitted large parts of the world had been as warm as they were now for decades at a time between 950 and 1250, centuries before the Industrial Revolution.

And, The Daily Mail said, a forecast in the 2007 report that hurricanes would become more intense had been dropped.

Writing in The Wall Street Journal, Matt Ridley said the draft report had revised downwards the “equilibrium climate sensitivity”, a measure of eventual warming induced by a doubling of carbon dioxide in the atmosphere. It had also revised down the Transient Climate Response, the actual climate change expected from a doubling of atmospheric carbon dioxide about 70 years from now.

Ridley said most experts believed that warming of less than 2C from pre-industrial levels would result in no net economic and ecological damage. “Therefore, the new report is effectively saying (based on the middle of the range of the IPCC’s emissions scenarios) that there is a better than 50-50 chance that by 2083 the benefits of climate change will still outweigh the harm,” he said.

Global Cooling: Arctic Ice Cap Grows 60%

8 Sep

Nice timing.

Just as Australia gets a new government. One that has made a “blood pledge” to “scrap the carbon tax”, and the $10 billion “green bank”.

From the UK’s The Mail on Sunday:

Record return of Arctic ice cap as it grows by 60% in a year with top scientists warning of global COOLING

  • Almost a million more square miles of ocean covered with ice than in 2012
  • BBC reported in 2007 global warming would leave Arctic ice-free in summer by 2013
  • Publication of UN climate change report suggesting global warming caused by humans pushed back to later this month

A chilly Arctic summer has left nearly a million more square miles of ocean covered with ice than at the same time last year – an increase of 60 per cent.

The rebound from 2012’s record low comes six years after the BBC reported that global warming would leave the Arctic ice-free in summer by 2013.

Instead, days before the annual autumn re-freeze is due to begin, an unbroken ice sheet more than half the size of Europe already stretches from the Canadian islands to Russia’s northern shores.

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Click to enlarge

The Northwest Passage from the Atlantic to the Pacific has remained blocked by pack-ice all year. More than 20 yachts that had planned to sail it have been left ice-bound and a cruise ship attempting the route was forced to turn back.

Some eminent scientists now believe the world is heading for a period of cooling that will not end until the middle of this century – a process that would expose computer forecasts of imminent catastrophic warming as dangerously misleading.

The disclosure comes 11 months after The Mail on Sunday triggered intense political and scientific debate by revealing that global warming has ‘paused’ since the beginning of 1997 – an event that the computer models used by climate experts failed to predict.

In March, this newspaper further revealed that temperatures are about to drop below the level that the models forecast with ‘90 per cent certainty’.

The pause – which has now been accepted as real by every major climate research centre – is important, because the models’ predictions of ever-increasing global temperatures have made many of the world’s economies divert billions of pounds into ‘green’ measures to counter  climate change.

Those predictions now appear gravely flawed.

The continuing furore caused by The Mail on Sunday’s revelations – which will now be amplified by the return of the Arctic ice sheet – has forced the UN’s climate change body to hold a crisis meeting.

The UN Intergovernmental Panel on Climate Change (IPCC) was due in October to start publishing its Fifth Assessment Report – a huge three-volume study issued every six or seven years. It will now hold a pre-summit in Stockholm later this month.

Leaked documents show that governments which support and finance the IPCC are demanding more than 1,500 changes to the report’s ‘summary for policymakers’. They say its current draft does not properly explain the pause.

At the heart of the row lie two questions: the extent to which temperatures will rise with carbon dioxide levels, as well as how much of the warming over the past 150 years – so far, just 0.8C – is down to human greenhouse gas emissions and how much is due to natural variability.

In its draft report, the IPCC says it is ‘95 per cent confident’ that global warming has been caused by humans – up from 90 per cent in 2007.

This claim is already hotly disputed. US climate expert Professor Judith Curry said last night: ‘In fact, the uncertainty is getting bigger. It’s now clear the models are way too sensitive to carbon dioxide. I cannot see any basis for the IPCC increasing its confidence level.’

She pointed to long-term cycles  in ocean temperature, which have a huge influence on climate and  suggest the world may be approaching a period similar to that from 1965 to 1975, when there was a clear cooling trend. This led some scientists at the time to forecast an imminent ice age.

Professor Anastasios Tsonis, of the University of Wisconsin, was one of the first to investigate the ocean cycles. He said: ‘We are already in a cooling trend, which I think will continue for the next 15 years at least. There is no doubt the warming of the 1980s and 1990s has stopped.

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Click to enlarge

‘The IPCC claims its models show a pause of 15 years can be expected. But that means that after only a very few years more, they will have to admit they are wrong.’

Others are more cautious. Dr Ed Hawkins, of Reading University, drew the graph published by The Mail on Sunday in March showing how far world temperatures have diverged from computer predictions. He admitted the cycles may have caused some of the recorded warming, but insisted that natural variability alone could not explain all of the temperature rise over the past 150 years.

Nonetheless, the belief that summer Arctic ice is about to disappear remains an IPCC tenet, frequently flung in the face of critics who point to the pause.

Yet there is mounting evidence that Arctic ice levels are cyclical. Data uncovered by climate historians show that there was a massive melt in the 1920s and 1930s, followed by intense re-freezes that ended only in 1979 – the year the IPCC says that shrinking began.

Professor Curry said the ice’s behaviour over the next five years would be crucial, both for understanding the climate and for future policy. ‘Arctic sea ice is the indicator to watch,’ she said.