Wednesday, 29 January 2014

Testimony Judith Curry on Arctic temperature seems to be a misquotation

Looks like the IPCC is not even wrong.

There has been a heated debate between Judith Curry (Climate Etc.) and Tamino (Open Mind) about the temperature in the Arctic. This debate was initiated by Curry's testimony before congress two weeks ago.

In her testimony Judith Curry quotes:
“Arctic temperature anomalies in the 1930s were apparently as large as those in the 1990s and 2000s. There is still considerable discussion of the ultimate causes of the warm temperature anomalies that occurred in the Arctic in the 1920s and 1930s.” (AR5 Chapter 10)
Tamino at Open Mind investigated this claim and found that recent temperatures were clearly higher as in the beginning of the 20th century. In his post (One of) the Problem(s) with Judith Curry Tamino concludes that the last IPCC report and Curry's testimony are wrong about the Arctic temperature increase:
"I think the IPCC goofed on this one — big-time — and if so, then Curry’s essential argument about Arctic sea ice is out the window. I’ve studied the data. Not only does it fail to support the claim about 1930s Arctic temperatures, it actually contradicts that claim. By a wide margin. It ain’t even close."

That sounded convincing, but I am not so sure about the IPCC any more.

Tamino furthermore wonders where Curry got her information from. I guess he found it funny that Judith Curry would quote the IPCC as a reliable source without checking the information. Replying to another question of mine, Judith Curry replied on twitter that she indeed got her information from the last (draft) IPCC report:


Later she also wrote a reply on her blog, Climate Ect., starting with the above quote from the IPCC report.

Then the story takes a surprising turn, when Steve Bloom hidden in a large number of comments at AndThenTheresPhysics notes that the quote is missing important context. The full paragraph in the IPCC namely reads (my emphasis and the quote in Curry's testimony in red):
A question as recently as six years ago was whether the recent Arctic warming and sea ice loss was unique in the instrumental record and whether the observed trend would continue (Serreze et al., 2007). Arctic temperature anomalies in the 1930s were apparently as large as those in the 1990s and 2000s. There is still considerable discussion of the ultimate causes of the warm temperature anomalies that occurred in the Arctic in the 1920s and 1930s (Ahlmann, 1948; Veryard, 1963; Hegerl et al., 2007a; Hegerl et al., 2007b). The early 20th century warm period, while reflected in the hemispheric average air temperature record (Brohan et al., 2006), did not appear consistently in the mid-latitudes nor on the Pacific side of the Arctic (Johannessen et al., 2004; Wood and Overland, 2010). Polyakov et al. (2003) argued that the Arctic air temperature records reflected a natural cycle of about 50–80 years. However, many authors (Bengtsson et al., 2004; Grant et al., 2009; Wood and Overland, 2010; Brönnimann et al., 2012) instead link the 1930s temperatures to internal variability in the North Atlantic atmospheric and ocean circulation as a single episode that was sustained by ocean and sea ice processes in the Arctic and north Atlantic. The Arctic wide temperature increases in the last decade contrast with the episodic regional increases in the early 20th century, suggesting that it is unlikely that recent increases are due to the same primary climate process as the early 20th century. IPCC(2014, draft, page 10-43 to 10-44).

Steve Bloom dryly comments: "So it was a question in 2007." In other words, the IPCC was right, but Judith Curry selectively quoted from the report. That first sentence is very important, also the age of the references could have revealed that this paragraph was not discussing the current state-of-the-art. The data of the last six years makes a large difference between "with some goodwill in the same range of temperatures" to "clearly higher Arctic temperatures".

This is illustrated by one of the figures from Tamino's post, presenting the data:


This is the annual average temperature in the Arctic from 60 to 90 degrees North as computed by the Berkeley Earth Surface Temperature group. The smooth red line is computed using LOESS smoothing.

And the misquotation is not for lack of space in the testimony. In her blog post, Curry quotes may sections of the IPCC report at length and also the entire paragraph like it is displayed here, just somehow without the first sentence printed here in bold, the one that provides the important context.


Related reading


The congressional Testimony by Curry: STATEMENT TO THE COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS OF THE UNITED STATES SENATE Hearing on “Review of the President’s Climate Action Plan" 16 January 2014, Judith A. Curry.

(One of) the Problem(s) with Judith Curry by Tamino at Open Mind.

The reply by Curry about Tamino's post on her blog, Climate ect.

The answer to that by Tamino suggests that Curry's reply is not that convincing.

Also Robert Way contributed to the discussion at Skeptical Science: "A Historical Perspective on Arctic Warming: Part One". Robert Way made the round in the blog-o-sphere with the paper Cowtan and Way (2013), where they studied the recent strong warming in the Arctic and suggested that that may explain a part of the recent slowdown in the warming of surface temperature.

A previous post of mine of Curry's testimony, focussing on her suggestive, but non-committal language: "Interesting what the interesting Judith Curry finds interesting".

14 comments:

Steve Bloom said...

Thanks again, Victor!

You may want to make it clear that in the AR5 there's no paragraph break between the missing sentence and the bit Judy quotes.

Victor Venema said...

I wrote: "my emphasis and paragraphs", to make clear the paragraphs were mine, but I guess I should solve that problem differently.

I wanted to highlight the part Curry cited, but could not use italics as it is already in italics. Let's see if I can add some colour.

Arthur said...

Hi Victor,

Judith Curry quotes a longer excerpt from the draft IPCC report that does NOT include your prefacing sentence, in her latest blog post on the matter (response to Tamino). Also on Tamino's post here Paul S notes that the "and 2000s" was not there in early drafts. Something fishy here?

Steve Bloom said...

Thanks for the clarifying fix, Victor.

Arthur, I noted the first of those issues over at ATTP. The second would seem to be explained by the fact that the referenced study indeed covers part of the 2000s, i.e. the correction seems appropriate.

Rachel said...

I do think the wording used by the IPCC could have been better. Rather than use the word "apparently" (which I must admit confused me when I first read that sentence), it would have been more difficult to misquote had they instead said,

"Arctic temperature anomalies in the 1930s were thought to be as large as those in the 1990s and 2000s."

Steve Bloom said...

The report is riddled with clumsy verbiage, Rachel. They are scientists, not English majors. :)

Paul S said...

Steve Bloom,

If 'the referenced study' means Serreze et al. 2007 note that it doesn't talk about 1930s temperatures at all, so linking that paper to a comparison of either 1990s or 2000s temperatures doesn't fit.

Nevertheless it does make sense if you understand '2000s' to refer only to the portion of the 2000s visible from 2007 i.e. 2000-2005/6. In some datasets the early-2000s are roughly comparable to the 1990s and the 1930s. Also, the two opening sentences were copy & pasted around together between drafts which would suggest they are intended to be a couplet.

I think treating this as a clear case of misquotation is going a bit far. The sentence is ambiguous even with the context of the surrounding paragraph. By the same token I can't see why we would expect Judith to include the previous sentence in her quote - it isn't obviously relevant to her point.

Arthur said...

Paul S - but in this post Curry claims the full quote is:

"Gillett et al. (2008b) detect anthropogenic influence on near-surface Arctic temperatures over land, with a consistent magnitude in simulations and observations. Wang et al. (2007) also find that observed Arctic warming is inconsistent with simulated internal variability. Both studies ascribe Arctic warmth in the 1930s and 1940s largely to internal variability. Shindell and Faluvegi (2009) infer a large contribution to both midcentury Arctic cooling and late century warming from aerosol forcing changes, with greenhouse gases the dominant driver of long-term warming, though they infer aerosol forcing changes from temperature changes using an inverse approach which may lead to some changes associated with internal variability being attributed to aerosol forcing. We therefore conclude that despite the uncertainties introduced by limited observational coverage, high internal variability, modelling uncertainties (Crook et al., 2011) and poorly understood local forcings, such as the effect of black carbon on snow, there is sufficiently strong evidence to conclude that it is likely that there has been an anthropogenic contribution to the very substantial warming in Arctic land surface temperatures over the past 50 years.

Arctic temperature anomalies in the 1930s were apparently as large as those in the 1990s and 2000s. There is still considerable discussion of the ultimate causes of the warm temperature anomalies that occurred in the Arctic in the 1920s and 1930s (Ahlmann, 1948; Veryard, 1963; Hegerl et al., 2007a; Hegerl et al., 2007b). The early 20th century warm period, while reflected in the hemispheric average air temperature record (Brohan et al., 2006), did not appear consistently in the mid-latitudes nor on the Pacific side of the Arctic (Johannessen et al., 2004; Wood and Overland, 2010). Polyakov et al. (2003) argued that the Arctic air temperature records reflected a natural cycle of about 50–80 years. However, many authors (Bengtsson et al., 2004; Grant et al., 2009; Wood and Overland, 2010; Brönnimann et al., 2012) instead link the 1930s temperatures to internal variability in the North Atlantic atmospheric and ocean circulation as a single episode that was sustained by ocean and sea ice processes in the Arctic and north Atlantic. The Arctic wide temperature increases in the last decade contrast with the episodic regional increases in the early 20th century, suggesting that it is unlikely that recent increases are due to the same primary climate process as the early 20th century. […]"

And the sentence Steve and Victor have pointed out is missing. Why? Is she using a different source, or did she deliberately drop that sentence???

Paul S said...

Arthur,

Those paragraphs (three in total on her blog post) aren't adjacent in Chapter 10. The first one is actually in a different section. She hasn't copy and pasted one chunk but three separate chunks.

While the second paragraph is quoted in its entirety the third paragraph is also missing a couple of sentences off the end.

I'll admit it is strange to miss off just the header sentence from that paragraph since that would generally provide important context for what's being said.

Victor Venema said...

Arthur, at her blog, Curry put such long quotes and also the paragraph in question is so long, that I see no excuse for leaving out an important and quite short first sentence.

HotWhopper now also has a long post on Curry and the Arctic and also shows the part missing at the end of the third quoted paragraph, Paul S is talking about.

Victor Venema said...

Rachel, yes your formulation sounds much better, if it still fits to the references. (I do not know whether they just showed some graphs or also gave their thoughts about the temperature difference between then and 1990s-2000s.)

I do not think you can write such a long report, while making sure that none of the sentences can be taken out of context to make wrong claims. Even if that is possible, the scientist writing that part will not have expected such behaviour, that is simply not done in science.

I think is is clear that the IPCC intended to write about the situation in 2007 and not about the most recent temperature observations because the references are: "Ahlmann, 1948; Veryard, 1963; Hegerl et al., 2007a; Hegerl et al., 2007b". In other words, the newest reference was 6 years old.

Victor Venema said...

Paul S: "I think treating this as a clear case of misquotation is going a bit far. The sentence is ambiguous even with the context of the surrounding paragraph. By the same token I can't see why we would expect Judith to include the previous sentence in her quote - it isn't obviously relevant to her point."

I was a bit careful yesterday, as I like to sleep a night over a post, but in this case thought it was too newsworthy to wait a day.

Today, I would say that Curry made a clear misquotation. It makes an enormous difference whether we are talking about the last few years (before 2013) or the years before 2007. Given the strong increase in Arctic temperature seen in Tamino's figure, these six years are very important.

Interpreting the claim as being about the situation before 2007 is already at the boundary. Already in 2007, I would have chosen a formulation that makes clear that the most recent temperatures are higher, but with some good will that vague formulation was still acceptable for the situation then. (Like you wrote at Tamino: That the formulation turned out that way is most likely because originally the sentence was about the 1990s and in a later stage the 2000s was added. Had it been written from scratch about the 2000s as well, it would likely have been formulated differently.)

The formulation is surely not acceptable as describing the situation now and that is what Curry made it into by leaving out the important first sentence.

In scientific writing you do not expect to find such misquotations. I will read texts written by Curry the way I read a WUWT post, expecting every single sentence to be wrong until proven innocent.

Arthur said...

Paul - oh my! I just saw Sou's post about this as well at HotWhopper. The fact that she joined those three paragraphs together as if they were together, and OMITTED various sentences in them that detract from her claims is that much more damning. This is very clearly a case of deliberate misquotation. No excuse at all.

Victor Venema said...

I would personally have indicated that the paragraphs are not consecutive. Just three dots at the end of the paragraph would do so. ...

However, as long as that does not change the interpretation of the text, I feel that not doing so is acceptable.