To be certain sensitivity is still uncertain...

This is a follow-on from my earlier article about a new paper on climate sensitivity. It isn't a critique or analysis of the paper itself. Maybe other people will look at the work and how it differs from other sensitivity analysis. This is more about the reaction in the deniosphere with some of my meandering thoughts rolled in. I've been in two minds about whether to publish this because there are no firm conclusions. It's rather long-winded and a bit repetitive. But I don't feel like spending any more time editing it down. You can make of it what you will.

As you may know, the denialati are all over a new paper in Climate Dynamics by Nic Lewis and Judith Curry, who have taken a shot at estimating climate sensitivity. You can download a pre-publication pdf version here, together with supplementary information zipped here, courtesy Nic Lewis.

It's not at all odd that deniers would latch on to it when you think about it, even though the WUWT crowd variously "believe":

• Climate change isn't happening
• Climate change is always happening
• If the world is warming, it's not because of CO2 (ie climate sensitivity to CO2 is zero)
• There is no such thing as a greenhouse effect. The world is warmed by magic.
• The world is cooling
• We're heading for an ice age
• The increase in CO2 is not caused by humans (ie burning hydrocarbons doesn't release CO2)
• Atmospheric CO2 hasn't increased

One reason I say this isn't surprising is because even though the paper suggests the world is about to get a lot hotter, the authors argue a likelihood, or at least a possibility, that the surface may not get quite as hot, with a doubling of CO2, as a lot of other research suggests. This paper suggests that when CO2 hits 560 ppm later this century, Earth will at first be somewhere between 0.9°C and 2.5°C hotter than it was in the mid-1800s. And even if we stopped adding any more CO2 to the atmosphere at that point, temperatures would continue to rise, settling at between 1°C and 4°C hotter as the system approaches medium term equilibrium. None of which is by any means comforting. While these numbers extend almost to the same range as stated in the latest IPCC report (1.5°C to 4.5°C), it goes below the lower end of the IPCC most like range and doesn't hit the high end.

That's not quite an apples to apples comparison though. Lewis and Curry were looking at "effective" climate sensitivity which is not quite the same as equilibrium climate sensitivity. The difference as far as I can make out is as follows. "Effective" is on a centennial time scale whereas equilibrium is on a millenial time scale. "Equilibrium" refers to after the ice sheets stop melting and maybe even after the ocean circulation has stopped responding to climate change. The deep ocean circulation has a cycle of around a thousand years. Ice sheets can take several millenia to settle down after a climate forcing.

So all in all, the difference between Lewis and Curry and other estimates is one of a few tenths of a degree at most.

Judith Curry vanquishes her uncertainty monster

Wonderful news just announced. Judith Curry has vanquished her uncertainty monster. She did it with the help of UK financier (retired), Nic Lewis.

Judith and Nic sat down and puzzled over the challenge for a bit. Then they decided to tackle the monster head on. They've announced their victory in Climate Dynamics.

Not only has Judith killed off her uncertainty monster, she's done an about face on her George C Marshall / op ed of just a couple of days ago. She's announced that the impact of all our waste CO2 can indeed be detected - not just on centennial time scales but on decadal time scales, or at least on multi-decadal time scales.

Here you go. According to Judith and Nic, using an energy balance approach and after much protesting of climate models:

• Median ECS** is, with very little uncertainty, equal to 1.64K (1.05 to 4.05K at 5-95%)
• Median TCR is, with almost no uncertainty left at all, 1.33K (0.9 to 2.5K at 5-95%)

**ECS is defined as "effective climate sensitivity", on a shorter time scale than equilibrium climate sensitivity.

Oh, and if you're a retired financier, it's okay to publish reviewers' comments.

One more thing. The IPCC is now back in Judith's good books. She even says she uses forcings from the IPCC's AR5 WG1 report. (What would they have done if Judith had succeeded in disbanding the IPCC. Horror of horrors. That uncertainty monster would still be roaming snatching unwary climate scientists.)

Wonders will never cease!

Here's the archive of the WUWT article, which was personally sent to Anthony Watts by the host of his extraordinary dinner, Nic Lewis. Here's the link that Nic provided to his and Judith's brilliant new paper, which has in one fell swoop solved all the world's ills.

PS If I come across as a mite sarcastic, put it down to my being quite underwhelmed by the swings and roundabouts of the past week at Judith's place.

Anthony Watts meets some scientists - "Extraordinary" sez Anthony

Anthony Watts got to meet some real scientists this week. His trip to the UK wasn't a complete waste of his fans money.

(Anthony ostensibly went to the UK to attend talks by John Cook and Michael Mann. He wrote a substance-free "report" of John Cook's talk and so far hasn't written anything about Michael Mann's talk. Nor did he ask either of them any of his "many" questions. Nor has he mentioned anything about any presentations. The people who paid for his trip could be forgiven if they felt diddled.)

Despite my scepticism, I don't want to spoil any goodwill that may have been created this week, so I'll try to be careful. I might not always succeed, so be warned.

Around the traps: GWPF and global warming, BEST daily temperatures and an El Niño watch

Some blog articles worth reading.

Ed Hawkins (and others) on a GWPF article on climate sensitivity

First Ed Hawkins has written about some article Nic Lewis and Marcel Crok wrote for the GWPF.  Actually it was two articles reports, a short version with 44 pages cover to cover and a long version with 72 pages cover to cover.  Ed makes the point that not before time is the GWPF acknowledging that we are heading to dangerous warming of more than two degrees by the end of the century if we keep burning fossil fuels at the rate we are.  The other points he makes are about why Nic Lewis is probably erring on the low side in his estimate of climate sensitivity.

Greg Laden has also written a good article on the topic of the Lewis and Crok article, which you can read here.  Bob Ward took down Nic Lewis' recent testimony to a UK parliamentary committee (along with that of other deniers).

I can't really add anything to what these people have written, except to say that Judith Curry wrote a foreword to Nic and Marcel's articles, with effusive praise for Nic and Marcel and slightly more muted "appreciation" for the GWPF.  Plus maybe a hint that they asked her to find a publisher, which she couldn't manage to do.

While writing this Foreword, I considered the very few options available for publishing a report such as this paper by Lewis and Crok. I am appreciative of the GWPF for publishing and publicizing this report. Public accountability of governmental and intergovernmental climate science and policy analysis is enhanced by independent assessments of their conclusions and arguments.

Victor Venema on the daily temperature dataset from BEST

The other article I'll point you to is by Victor Venema.  He's saying "Be careful with the new daily temperature dataset from Berkeley".  And continues:

The Berkeley Earth Surface Temperature project now also provides daily temperature data. On the one hand this is an important improvement, that we now have a global dataset with homogenized daily data. On the other hand, there was a reason that climatologists did not publish a global daily dataset yet. Homogenization of daily data is difficult and the data provided by Berkeley is likely better than analyzing raw data, but still insufficient for robust conclusions about changes in extreme weather and weather variability.

It's worth a read - Victor is a specialist in climate temperature data.

RealClimate has an article by Zeke Hausfather and Robert Rohde, two of the BEST team members behind the new data set.

Jeff Masters on El Niño watch

You read it here at HotWhopper first of course :)  Then NOAA announced it.  Jeff Masters has now written about it too. There may be an El Niño on its way later this year.

Jeff points to this earlier article by Michael Ventrice at wunderground.com that is worth reading. (I wrote something about ENSO here some weeks ago, which has more links to the subject,)

Update: Webb Roberts ‏(@webbr) pointed me to another article about this from Kim Cobb's Lab at Georgia Tech, suggesting it could provide a rare opportunity for scientific study and learning more about ENSO, if resources can be put together in time.

Disinformer David Rose of the Daily Mail takes another denialist "swinge"

Update: The UK Met Office has commented on David Rose's latest article.

Serial disinformer David Rose from the tabloid rag the Daily Mail doesn't care about facts, only headlines.  He's come out with another "not even wrong" article (archived here) as a follow up to his last one.

David starts with a false headline: Global warming is just HALF what we said: World's top climate scientists admit computers got the effects of greenhouse gases wrong

Unsurprisingly, David doesn't cite any of the world's top scientists so I figure he just made that up.  It's what he does - see here and here and here and here and here and here and here (and more here).

David Rose "swinges" about clean energy and taxation

David could hardly be seen as more "wrong" if he wore a sandwich board saying "I reject and deny science". He goes on to write about the IPCC reports that "they are cited worldwide to justify swingeing (sic) fossil fuel taxes and subsidies for ‘renewable’ energy".

Now we've got his reason for rejecting science out of the way (he prefers dirty energy and doesn't like paying tax), let's see what lies he's spouting this time.

David Rose flunks arithmetic

Remember his headline of just HALF? In addition to wanting dirty energy and not liking taxation, David Rose can't do simple sums, he writes:

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.

David, like some other deniers we know, fails at arithmetic.  0.12 is 60% of 0.2, not 50%.  That amount of difference can make or break a candidate's hope for re-election :D

David also lied.  Here is what is written in the IPCC AR4 report - a linear trend from 1956 to 2005 = 0.13°C per decade. Not a 0.2°C per decade in sight!

If anything, the linear trend has increased!

Do you still wonder about David's implied claim that the IPCC said the world has warmed at 0.2 degrees since 1951 and is only warming at 50% of that - or 60% if you use David's numbers rather than his wrong calculation?  What I think he must have done is try to convince his readers that the modeled projection for future temperature rises under a "business as usual" scenario was the same as the actual rise since 1951.  But who knows.  The mind of the science denier is a tangle of lies and disinformation and it's not for me to try to fathom.

So instead let's look at the record itself.  Here is a chart of global average surface temperature from 1951 to the present, and from 1951 to 2006 - the last full year before the publication of IPCC's AR4 report:

Interesting, eh.  To get a very rough estimate, subtract the value at the bottom of the trend line (the straight line) from the value at the top of the trend line, divide by the number of years and multiply by ten.  (But don't tell Tamino I said this!)  If you do the sums you'll get the following:

• 1951-2006 trend ~ 0.124 degrees per decade
• 1951-2012 trend ~ 0.127 degrees per decade.

If you want to quibble about decimal places, let's round it to two decimal places.  The linear trend has increased from 0.12 degrees a decade for 1951 to 2006 to to 0.13 degrees a decade for 1951 to 2012!

David Rose has a lot of cheek, too.  Pretending that he "first reported" a pause.  He doesn't say, but what he is most likely referring to is another slab of lies and disinformation that the Met Office called him out on - here and here.

The Incomprehensible Judith Curry

I'll mention that David quotes Judith Curry (scientist turned denying fan of David Rose) as saying it's "incomprensible to me" that the IPCC would state, very conservatively, that it is 95% certain that humans have caused more than half the temperature rise from 1951 to 2010.  Some science suggests we've caused more than 100% of the rise in temperature since the 1950s.  Here's an article on realclimate.org about attribution and one on SkepticalScience, with this chart:

Figure 1: Net human and natural percent contributions to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple),Huber and Knutti 2011 (HK11, light blue), and Gillett et al. 2012 (G12, orange). . 
Source: SkepticalScience.com

Going by David Rose's record, I won't take it as read that Judith Curry did say that.  However there is little that she says these days that surprises me.  She could claim tomorrow that the moon was made of cheese and it wouldn't surprise me.  Although she probably wouldn't be categorical and would add "but there is a lot of uncertainty" and "we can't be sure if it's Italian cheese". (Apologies to Italians and their wonderful cheeses.)

And he has a long blurb about how Nic Lewis, who is not a climate scientist, reckons he knows a lot more about climate than do the meteorologists at the UK Met.  I can't follow that bit at all.  Here is a report of decadal forecasting by the UK Met Office and a link to information on its HADCM3 model.

This article is more of a mish mash than other articles by David Rose.  It hops and skips and jumps all over the place.  I'd say he's rattled.  He denies the science but is finding it hard to balance his denial with his possible desire to be viewed as anything but another James Delingpole or Anthony Watts.

I won't bother** going into any more detail of the rest of it because it's a gish gallop of "the models are wrong", Bob Ward said his last article was "error strewn" (it was) and complaints about allusions to Nazis - which I myself abhor but which denialati more commonly resort to than do people who accept science.

Message to David Rose - you are just another denier who has somehow managed to hold down a job with a UK tabloid.  Try writing an article on UFOs and little green men from Mars and your typical fans will probably "believe" you.



** I ended up bothering, because it reappeared on WUWT and elsewhere.  Read more here.

Hat tip to Lars Karlsson in the comments.

On Climate Sensitivity, Otto and Hansen - and Exaggeration from WUWT

Update below: In which Anthony Watts tells his readers "she'll be right, mate" and to take no notice of what the lead author himself says.


Today WUWT has picked up another article on climate sensitivity.  The authors, Otto et al, seem to have taken a not dissimilar approach to Lewis (2013), in that they based their workings on surface temperatures in recent decades including the temperatures of the most recent decade.  Unlike some other studies of climate sensitivity, the work does not appear to refer to evidence from past climatology, prior to the period covered by instrumental records.

The authors provide best estimates of Equilibrium Climate Sensitivity as 2.0 °C based on 2000-09:

The most likely value of equilibrium climate sensitivity based on the energy budget of the most recent decade is 2.0 °C, with a 5–95% confidence interval of 1.2–3.9 °C, compared with the 1970–2009 estimate of 1.9 °C (0.9–5.0 °C). Including the period from 2000 to 2009 into the 40-year 1970–2009 period delivers a finite upper boundary...Observations of the energy budget alone do not rule out an ECS value below 2 °C, but they do rule out an ECS below 1.2 °C with 95% confidence. The upper boundary is lowered slightly, but is also very sensitive to assumptions made in the evaluation process (see Supplementary Section S2). Uncertainties include observational errors and internal variability estimated from control simulations with general circulation models.

And of Transient Climate Response at 1.3 °C (0.9–2.0 °C) based on 2000-09.

This is lower than estimates derived from data of the 1990s (1.6 °C (0.9–3.1 °C); yellow, or for the 1970–2009 period as a whole (1.4 °C (0.7–2.5 °C).

Here is the write up by the Guardian, and from the BBC.  The opening paragraphs from the Guardian are:

Some of the most extreme predictions of global warming are unlikely to materialise, new scientific research has suggested, but the world is still likely to be in for a temperature rise of double that regarded as safe.

The researchers said warming was most likely to reach about 4C above pre-industrial levels if the past decade's readings were taken into account.

That would still lead to catastrophe across large swaths of the Earth, causing droughts, storms, floods and heatwaves, and drastic effects on agricultural productivity leading to secondary effects such as mass migration.

Let's moderate that with a dose of stark reality from Dr James Hansen, the "grandfather" of modern climatology.

The Exaggeration? (Yes, but maybe not so much as I first thought - see update)

Nic Lewis in his WUWT article says this new work is a : "new peer-reviewed climate sensitivity study published as a Letter in Nature Geoscience".  The article itself, however, is not published as a Letter.  It is published as "Correspondence", which is described as "Correspondence provides readers with a forum for comment on papers published in a previous issue of the journal or to discuss issues relevant to the geosciences."  There is no indication that the work has been peer-reviewed (see following Update). Describing the article as a Letter, when it is in fact Correspondence is still wrong and arguably an exaggeration, but not the double exaggeration I previously and erroneously thought it might have been.  Not really worth quibbling about after all - see following update:D

Update: This from Nature GeoScience: "Other types of Correspondence may be peer-reviewed at the editors' discretion". Nature has since advised me the article was peer-reviewed.

Don't get me wrong.  I'm not doubting the rigour of the analysis.  And I would welcome any news that climate sensitivity is lower rather than higher.  On the other hand I'm not about to accept estimates based largely on recent instrumental temperature records as the final word on the matter.  Particularly not when there are other studies of actual past climate change that suggest climate sensitivity may well be at the high end of the scale.  (Notice how Anthony Watts went all Dunning Kruger when he wrote about that paper).

Thing is, not one of us will be alive to see what is equilibrium climate sensitivity.  Some of us will, sadly, probably get to find out the transient climate sensitivity - at the time of doubling of CO2.  The medium and longer term effects we'll be leaving for future generations to grapple with.

Another Oddity

Another thing that's decidedly odd when you think about it.  Only a couple of days ago Anthony Watts was telling big fat lies about the 97% scientific consensus on global warming, trying to claim that more papers disagreed that humans are causing global warming than agree.  Now he seems to embrace a paper that assumes humans are causing global warming.  He also shows no lessening of his efforts to send us hurtling at warp speed (geologically speaking) towards a world that is too hot to handle.

I'll leave you with a comment from Anthony, whose frantic advocacy efforts to heat the world take him beyond rationality and morality.  Does he also lack any self-awareness?  Anthony Watts says:

May 19, 2013 at 3:08 pm  @Mosher I agree. Cook and Co. are advocates, so like Romm, they tend to do those sorts of things. Now, it appears Cook and Nuccitelli have reached the level of paid advocates.

Update: Watts tells his readers to take no notice of the authors

In a follow up article entitled: "Why the new Otto et al climate sensitivity paper is important – it’s a sea change for some IPCC authors" there is more ridiculous wishful thinking from Anthony Watts.  As if to prove the denier watcher's correct he writes:

With the modest rate of warming stated by Otto et al, the impacts of global warming are more likely to be positive than negative for humanity in the foreseeable future; increased crop yields for example.

Watts lauds the article, calling it a "sea change", but at the same time he dismisses out of hand what the lead author himself is quoted as saying with a sneering "Oh, sure":

Anthony snorts: The BBC says they had it all covered before and this new paper is “consistent” with previous works. Oh, sure.

Quoting the BBC:…when it comes to the longer term picture, the authors say their work is consistent with previous estimates. The IPCC said that climate sensitivity was in the range of 2.0-4.5C.

This latest research, including the decade of stalled temperature rises, produces a range of 0.9-5.0C.

“It is a bigger range of uncertainty,” said Dr Otto.

“But it still includes the old range. We would all like climate sensitivity to be lower but it isn’t.”

Let's add comments from Dr Sherwood, who is urging caution about assuming low climate sensitivity just based on the past decade:

Prof Steven Sherwood, from the University of New South Wales, says the conclusion about the oceans needs to be taken with a grain of salt for now.

"There is other research out there pointing out that this storage may be part of a natural cycle that will eventually reverse, either due to El Nino or the so-called Atlantic Multidecadal Oscillation, and therefore may not imply what the authors are suggesting," he said.

And finish with the final remarks from the lead author, Dr Otto - from the same BBC article - aimed squarely at deniers like Anthony Watts who wrote: "Meanwhile, in lower sensitivity land, “the pause” in global temperatures continues, and is approaching the Santer definition":

Is there any succour in these findings for climate sceptics who say the slowdown over the past 14 years means the global warming is not real?

"None. No comfort whatsoever," he said.