Climate Change – United Nations IPCC Is More Sure About Less

Posted on Sat 09/28/2013 by

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Bolt New 01By Andrew Bolt ~

On the IPCC report…UNIPCCLogoLarge

A significant mistake may have been made. Doug Keenan writes to the Met Office Chief Scientist about this problem:

Dear Julia,

The IPCC’s AR5 WGI Summary for Policymakers includes the following statement.

The globally averaged combined land and ocean surface temperature data as calculated by a linear trend, show a warming of 0.85 [0.65 to 1.06] °C, over the period 1880–2012….

(The numbers in brackets indicate 90%-confidence intervals.) The statement is near the beginning of the first section after the Introduction; as such, it is especially prominent.

The confidence intervals are derived from a statistical model that comprises a straight line with AR(1) noise.  As per your paper ”Statistical models and the global temperature record” (May 2013), that statistical model is insupportable, and the confidence intervals should be much wider—perhaps even wide enough to include 0°C.

It would seem to be an important part of the duty of the Chief Scientist of the Met Office to publicly inform UK policymakers that the statement is untenable and the truth is less alarming.  I ask if you will be fulfilling that duty, and if not, why not.

UPDATE

Alarmist media outlets are hanging their hat on the IPCC being even more sure humans are heating the earth, even though there’s been no significant warming for 15 years – which is not what they expected. For example, from The Age:

It is more certain than ever that human civilisation is the main cause of global warming, putting the world on track for dangerous temperature rises, the latest major UN assessment of climate change science has found.

The Intergovernmental Panel on Climate Change says it is “extremely likely” that humans are the dominant cause of observed warming since the mid-20th century, with carbon dioxide emissions the main factor.

It’s a neat propaganda trick, where the certainty becomes the news – rather than the admission that there was less warming to be certain about.

So much depends on just how that extra certainty was calculated – from 90 per cent sure last time to 95 per cent now. Thing is, Professor Judith Curry can’t see where this came from:

Yesterday, a reporter asked me how the IPCC came up with the 95% number.  Here is the exchange that I had with him:

Reporter:  I’m hoping you can answer a question about the upcoming IPCC report. When the report states that scientists are “95 percent certain” that human activities are largely to cause for global warming, what does that mean? How is 95 percent calculated? What is the basis for it? And if the certainty rate has risen from 90 in 2007 to 95 percent now, does that mean that the likelihood of something is greater? Or that scientists are just more certain? And is there a difference?

JC:  The 95% is basically expert judgment, it is a negotiated figure among the authors.  The increase from 90-95% means that they are more certain.  How they can justify this is beyond me.

Reporter:  You mean they sit around and say, “How certain are you?” “Oh, I feel about 95 percent certain. Michael over there at Penn State feels a little more certain. And Judy at Georgia Tech feels a little less. So, yeah, overall I’d say we’re about 95 percent certain.” Please tell me it’s more rigorous than that.

JC:  Well I wasn’t in the room, but last report they said 90%, and perhaps they felt it was appropriate or politic that they show progress and up it to 95%.

Reporter:  So it really is as subjective as that?

JC:  As far as I know, this is what goes on.  All this has never been documented.

UPDATE 2

Andrew Montford on hiding the decline:

You would imagine that the document would review what was said last time round and how things have changed since that time, but you’d be wrong…

It would, for example, have been interesting for AR5 to discuss the increase in hurricane intensity that the AR4 SPM said was “likely” on the basis of the climate models. Instead, we get a veil drawn over the subject, with not a word on the hurricane drought in recent years.

Similarly, the divergence between model and observational estimates of long-term warming (effective climate sensitivity) is alluded to in opaque fashion in a footnote (“lack of agreement on values across lines of evidence”) rather than being tackled head on in a way that would make clear the difficulties scientists are having with the climate jigsaw.

The general theme of obscurantism runs across the document. Whereas in previous years the temperature records have been shown unadulterated, now we have presentation of a single figure for each decade; surely an attempt to mislead rather than inform. And the pause is only addressed with handwaving arguments and vague allusions to ocean heat.

Dr Roy Spencer on the surprising omission of a key variable:

A best estimate for climate sensitivity — unarguably THE most important climate change variable — is no longer provided, due to mounting contradictory evidence on whether the climate system really cares very much about whether there are 2, or 3, or 4, parts of CO2 per 10,000 parts atmosphere.

YET…the IPCC claims their confidence has DOUBLED (uncertainty reduced from 10% that 5%) regarding their claim that humans are most of the cause behind the warming trend in the last 50 years or so…

A round up of opinion at Watts Up With That.

Andrew Bolt is a journalist and columnist writing for The Herald Sun in Melbourne Victoria Australia.

Andrew Bolt’s columns appear in Melbourne’s Herald Sun, Sydney’s Daily Telegraph and Adelaide’s Advertiser. He runs the most-read political blog in Australia and hosts Channel 10’s The Bolt Report each Sunday at 10am. He is also heard from Monday to Friday at 8am on the breakfast show of radio station MTR 1377, and his book  Still Not Sorry remains very widely read.

Read more excellent articles from Andrew Bolt’s Blog . http://blogs.news.com.au/heraldsun/andrewbolt/