Myles' model mystery

The Science Media Centre has put out a response to the GWPF report here. I was struck by Myles' Allen's contribution:

Their [TCR] prediction of 1.35 degrees C is, even if correct, only 25% lower than the average of the general circulation models used in the IPCC 5th Assessment.  A 25% reduction in TCR means the warming we might have expected by 2050 might take until the early 2060s instead.  Their 5-95% range of uncertainty in TCR (kindly provided by Nic Lewis) is 0.9-2.5 degrees C, almost exactly in line with the range of the models shown in their figure (1.1-2.6 degrees C).

Compare this with what is said in the Lewis/Crok report (long version):

Click to read more ...

Sherwood's fabrication

The Guardian has a quote from Professor Stephen Sherwood of the University of New South Wales, in which he takes a pot shot at the Lewis Crok report.

The report is standard cherry-picking.  It offers no new evidence not already considered by the IPCC, relying very heavily on a few strands of evidence that seem to point toward lower sensitivity while ignoring all the evidence pointing to higher sensitivity.

It relies heavily on the estimate by Forster and Gregory, which was an interesting effort but whose methodology has been shown not to work; this study did not cause the IPCC to conclude that sensitivity had to be low, even though both Forster and Gregory were IPCC lead authors and were obviously aware of their own paper.

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IPCC hides the good news

From GWPF:

A new report published by the Global Warming Policy Foundation shows that the best observational evidence indicates our climate is considerably less sensitive to greenhouse gases than climate models are estimating.

The clues for this and the relevant scientific papers are all referred to in the recently published Fifth Assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). However, this important conclusion was not drawn in the full IPCC report – it is only mentioned as a possibility – and is ignored in the IPCC's Summary for Policymakers (SPM).

For over thirty years climate scientists have presented a range for climate sensitivity (ECS) that has hardly changed. It was 1.5-4.5°C in 1979 and this range is still the same today in AR5. The new report suggests that the inclusion of recent evidence, reflected in AR5, justifies a lower observationally-based temperature range of 1.25–3.0°C, with a best estimate of 1.75°C, for a doubling of CO2. By contrast, the climate models used for projections in AR5 indicate a range of 2-4.5°C, with an average of 3.2°C.

This is one of the key findings of the new report Oversensitive: how the IPCC hid the good news on global warming, written by independent UK climate scientist Nic Lewis and Dutch science writer Marcel Crok. Lewis and Crok were both expert reviewers of the IPCC report, and Lewis was an author of two relevant papers cited in it.

In recent years it has become possible to make good empirical estimates of climate sensitivity from observational data such as temperature and ocean heat records. These estimates, published in leading scientific journals, point to climate sensitivity per doubling of CO2 most likely being under 2°C for long-term warming, with a best estimate of only 1.3-1.4°C for warming over a seventy year period.

“The observational evidence strongly suggest that climate models display too much sensitivity to carbon dioxide concentrations and in almost all cases exaggerate the likely path of global warming,” says Nic Lewis.

These lower, observationally-based estimates for both long-term climate sensitivity and the seventy-year response suggest that considerably less global warming and sea level rise is to be expected in the 21st century than most climate model projections currently imply.

“We estimate that on the IPCC’s second highest emissions scenario warming would still be around the international target of 2°C in 2081-2100,” Lewis says.

The full report is here.

Update on Mar 6, 2014 by Bishop Hill

Piers Forster has penned a response at Ed Hawkins' Climate Lab Book site.

Phew

As readers may have gathered, I have been a bit preoccupied in recent days, mainly with helping GWPF on this that and the other. I think things are now going to ease off a bit, so I can devote a bit more time to blogging.

One project that has been keeping me busy was helping with the report by Nic Lewis and Marcel Crok on climate sensitivity. Marcel tweeted about this earlier today:

Nic Lewis and I will present our GWPF report "A Sensitive Matter: How the IPCC buried evidence showing good news about global warming" on Thursday March 6 in press centre Nieuwspoort (The Hague, The Netherlands). Lewis and I will both give a presentation. There are still tickets available. The meeting starts at 10 am (Dutch time). To register send an email to kantoor@groenerekenkamer.nl

Two versions of the report (long and short one) can be downloaded on Thursday from the GWPF website.

The short version one is directed at the layman while the full long one is for more technically minded readers. They should help to provide James Painter with the answers to the questions he posed the other day. There's also a Dutch language version coming.

There are quite a few other things on the go, and which are keeping me very busy. These will appear over the next few days, weeks and months.

Painter slipped

James Painter has an amusing article in The Conversation, the left-wing campaigning website paid for by your taxes.

In it he writes about certainty and uncertainty in the global warming debate and takes issue with Nigel Lawson's appearance on the Today programme (along with just about every other left-wing campaigning academic it seems).

Framing the climate challenge as risk assessment has been gaining considerable traction among some politicians. Lawson’s response to the question was to argue that even if there is a problem of global warming, it will have only marginal effects.

Click to read more ...

Deben and Kennedy sinking fast

This morning Lord Deben and David Kennedy of the Committee on Climate Change were questioned by the Energy and Climate Change Committee on the Fourth Carbon Budget.

It has everything - climate sensitivity, stadium waves, bickering over funding, and the splendid sight of the two witnesses flailing around for answers.

Start watching at 10:14.21. It's unmissable.

Update on Jan 8, 2014 by Bishop Hill

If you are on a mobile device, you may need to view the video via this link.

There must be some misunderstanding

The global warming debate is a tricky subject for leader and op-ed writers and you can always rely on there being some marvellous errors and misunderstandings when these generalists hold forth.

Today, the Sunday Times (£) carries a long opinion piece from Adam Boulton on the rise of the sceptics within the Conservative party. While we've seen hints of such a shift over the last few months, Boulton seems rather more certain than I am that it's a real phenomenon. He's also pretty sure that it's a mistake since swing voters are apparently more likely to be greens. I have no idea if this is true or not.

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A mysterious change of tune

Over at Climate Audit, Nic Lewis examines the strange divergence between observational and climate-model-based estimates of transient climate response. There's lots to enjoy, particularly for the more technically minded among us. But there's also something of a mystery:

So, in their capacity as authors of Otto et al. (2013), we have fourteen lead or coordinating lead authors of the WG1 chapters relevant to climate sensitivity stating that the most reliable data and methodology give ‘likely’ and 5–95% ranges for TCR of 1.1–1.7°C and 0.9–2.0°C, respectively. They go on to suggest that some CMIP5 models have TCRs that are too high to be consistent with recent observations. On the other hand, we have Chapter 12, Box 12.2, stating that the ranges of TCR estimated from the observed warming and from AOGCMs agree well. Were the Chapter 10 and 12 authors misled by the flawed TCR estimates included in Figure 10.20a? Or, given the key role of the CMIP5 models in AR5, did the IPCC process offer the authors little choice but to endorse the CMIP5 models’ range of TCR values?

Why would all these IPCC bigwigs say one thing in the primary literature and something completely different in the IPCC report?

I just can't imagine.

Buckle up

During the Energy and Climate Change Committee hearing last week, Peter Lilley asked the men from the Climate Change Committee what evidence would cause them to change their minds about global warming, a question that was fairly studiously avoided. Interestingly, Simon Buckle of the Grantham Institute has written to the FT (not online) to suggest what the reply should have been:

As a physicist, I would modify my view that we are conducting a dangerous experiment with the Earth’s climate if one or both of the following hypotheses were strongly supported by evidence.

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Costing the Earth resumes normal service

Costing the Earth resumed normal service at the BBC this week, with a panel of six adherents to the Working Group I orthodoxy discussing, erm, the Working Group I report. Featured voices were Julia Slingo, Mark Walport, Bjorn Lomborg, Mike Hulme, Mark Lynas, and Tony Grayling, Head of Climate Change and Communities at the Environment Agency. The decision to invite

• Walport, whose every appearance in the media in recent days has featured a regurgitation of the same somewhat irrelevant talking points, making it sound as if he is simply repeating the contents of his introductory briefing paper on climate, and
• Lynas whose claims to fame seem to revolve around having been wrong about nuclear, GM and the pause

... look kind of weird when viewed in the context of their decision that Nic Lewis was unworthy of consideration for any media appearances, either because (like Lynas) he is not an academic or because he was (like Slingo) mentioned in a David Rose article.

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New blogs on the block

A couple of new blogs for readers to bookmark

Paul Matthews needs no introduction as a regular BH commenter and general scourge of the IPCC. His new blog is here.

Also new is Euan Mearns' blog. Euan was at the important, but now defunct Oil Drum blog for a long time but has just started up his own outlet. This extract from his first article sounds intriguing:

Together with fellow climate blogger Dr Clive Best, I have spent several months this year analysing the impact of cloud cover on variance of the surface temperature record and we have two papers under review on this topic [6,7]. The conclusion of both studies is that Earth’s climate can be simply modelled using combined cloud cover and CO2 variance (with no feedbacks) pointing to an equilibrium climate sensitivity close to 1.3˚C.

Science Media Centre hits new lows

Read this from the Science Media Centre.

...the slowdown has risked becoming the bête noire of climate science.  It has been unfairly framed as (another) nail in the coffin for global warming – ‘You said it would get warmer and it hasn’t!’ – as though the failure of the temperature record to conform each year blows the whole evidence base out of the water.  Triumphant claims are made – erroneously – that the failure to warm has finally been revealed and that scientists (part of the conspiracy, naturally) have been keeping quiet about it. 

"..conform each year"?! "Conform at any point since the turn of the millennium" is the criticism.

Met Office concedes the error

Over the last day or so, Julia Slingo has sent a polite, but somewhat evasive response to Nic Lewis regarding his critique of the UKCP09 model. It can be seen here.

Nic Lewis's reaction is here. I don't think he is very impressed. The key exchange relates to the following paragraph in Slingo's paper:

Having said that, it is true that the relationship between historical aerosol forcing and equilibrium climate sensitivity (ECS) depicted in your Figure B1 is based only on the PPE. But we disagree with your assertion that the results from HadCM3 are fundamentally biased. It is certainly the case that versions of HadCM3 with low climate sensitivity and strongly negative aerosol forcing are incompatible with the broad range of observational constraints. But the key point is that the relationship between aerosol forcing and ECS is an emergent property of the detailed physical processes sampled in the PPE simulations.

Click to read more ...

Climate's great dilemma

I have an article up at the Spectator's Coffee House blog on that awful dilemma for the IPCC:

It will not be an easy task. However the IPCC chooses to deal with the problem the repercussions are unpleasant. They might try to explain away the warming hiatus in some way: the in-vogue explanation is that the heat that should have been in the atmosphere has escaped, undetected, to the deep oceans. Evidence to support this idea is, however, scant at best, and going down this route is going to involve the IPCC admitting that there is much about the climate system that is not yet understood. This will be a hard act to carry off while simultaneously claiming that they are certain that mankind caused most of the recent warming.

A message to Will Hutton

Dear Will (if you'll forgive the familiarity)

Thanks for the link in your Guardian post - much appreciated. There's lots I could take issue with in your post, but let me focus on the bit quoted below (and not just because it mentions me).

Science has not helped its own cause. The open science movement, and even the Royal Society, has become concerned that the quest to win commercial funding has made a growing number of scientists too anxious to make their science unique. Too many scientific papers are published in which researchers make it hard for others to reproduce their lab experiments. Key data are omitted.

Compared with what is happening in some drug and cancer research, climate change science is remarkably honest, reproducible and subject to open criticism: the IPCC insists on the best methodology. But for climate change sceptics such as Andrew Montford, Bjørn Lomborg or Nigel Lawson's influential Global Warming Policy Foundation, this is an inconvenient truth. Climate change science must be greeted with the same sense that science in general is fallible.

Your suggestion that the IPCC insists on the best methodology made me laugh. I don't suppose the intracacies of Bayesian statistics are your cup of tea, but you really should try to get your head around l'affaire Forster and Gregory. If you are reading this, Will, it is an example of climate science using the worst methodology - a methodology without any support among reputable statisticians - and the IPCC rewriting the results of people who used the best methodology.

You need to to expand your reading I think.

But thanks again for the link.