Von Storch on the models again

In a post at Klimazwiebel, Von Storch and Zorita have expanded onf the views they put forward in the discusion paper I mentioned the other day.

We want here to set straight some misinterpretations that may have arisen in the blogosphere, e.g. Bishophill, and may also have been present in the review processes by Nature as well.

The main result is that climate models run under realistic scenarios (for the recent past) have some difficulty in simulating the observed trends of the last 15 years, and that are not able to simulate a continuing trend of the observed magnitude for a total of 20 years or more. This main result does not imply that the anthropogenic greenhouse gases have not been the most important cause for the warming observed during the second half of the 20th century. That greenhouse gases have been responsible for, at least, part or even most of the observed warming, is not only based on the results of climate simulations, but can be derived from basic physical principles, and thus it is not really debated. It is important to stress that there is to date no realistic alternative explanation for the warming observed in the last 50 years. The effect of greenhouse gases is not only in the trend in global mean near-surface temperature, but has been also identified in the spatial pattern of the observed warming and in other variables, such as stratospheric temperature, sea-level pressure and others.

Although von Storch and Zorita talk of misinterpretations, I'm not sure there is any great difference between what they say here and what I concluded last week. At the time I said that the models are falsified - they run too hot. A model that had a slower rate of warming would not be. So a claim that part of the observed warming is anthropogenic is still scientifically tenable. How big a part is manmade is, given the failure of the models, anyone's guess.

I'm not, however, convinced that the only plausible explanation for the warming of the last 50 years is greenhouse gases. As I mentioned the other day, the IPCC looks set to conclude that there was a Medieval Warm Period. Last time I heard Rob Wilson discuss the matter, he said that the climate models couldn't even get the MWP in the right historical position, let alone explain its apparently large magnitude.

So once again I find myself returning to the point I make so often. The unknown unknowns are a big problem. Scientists would do themselves a favour if they recognised it.

[Comments will be tightly edited for relevance and tone]

Von Storch: models are falsified

Roddy Campbell points us to this discussion paper by Hans von Storch et al, which looks at the divergence between climate models and observations:

In recent years, the increase in near-surface global annual mean temperatures has emerged as considerably smaller than many had expected. We investigate whether this can be explained by contemporary climate change scenarios. In contrast to earlier analyses for a ten-year period that indicated consistency between models and observations at the 5% confidence level, we find that the continued warming stagnation over fifteen years, from 1998 -2012, is no longer consistent with model projections even at the 2% confidence level. Of the possible causes of the inconsistency, the underestimation of internal natural climate variability on decadal time scales is a plausible candidate, but the influence of unaccounted external forcing factors or an overestimation of the model sensitivity to elevated greenhouse gas concentrations cannot be ruled out. The first cause would have little impact of the expectations of longer term anthropogenic climate change, but the second and particularly the third would.

That seems quite important to me. Note also that "the heat's all in the deep oceans" doesn't seem to be on the table as an explanation.

Zorita on McShane and Wyner

Eduardo Zorita has an interesting review of McShane & Wyner's paper on the statistics of paleoclimate reconstructions. He takes them to task for not understanding the actual methods used by paleo people and in particular those used by Mann et al in the Hockey Stick papers. Although one can point to the foggy writing in MBH98 in defence of M and W, Eduardo's point that they should have worked more closely with paleo people is fair enough. That said, Eduardo does spend quite a lot of his review criticising the preamble to the paper rather than the guts of the thing.

When he does get onto the paper, he is less critical, but not convinced. He describes M&W's comparison of reconstructions based on proxies to those from various forms of noise as "interesting and probably correct" but doubts its usefulness because they have used a method that is not used by paleo people. I'm not sure about this - surely if there is a real temperature signal in the proxies, they should outperform noise regardless of the method?

There is a modicum of agreement on the last part of the paper though, with Zorita agreeing with M&W's conclusion that the uncertainties in paleo reconstructions have been underestimated. However, he says that this observation is...

...hardly revolutionary. Already the NRC assessment on millennial reconstructions and other later papers indicate that the uncertainties are much larger than those included in the hockey stick and that the underestimation of past variability is ubiquitous.

I guess the IPCC missed that memo.

Zorita on Smerdon

Eduardo Zorita has a must-read post up at Klimazwiebel, discussing a new paper by Smerdon et al. Michael Mann fans will be amused to read of geographical problems uncovered in some of Mann's papers, which will instantly bring to mind favourite episodes from the Hockey Stick story, like the Rain in Maine (falls mainly in the Seine) and the documentary records of East African climate from the medieval period (Mann et al 2008). Here's a sample:

In one case, when interpolating the climate model data onto a different grid, the data were rotated around the Earth 180 degrees, so that model data that should be located on the Greenwich Meridian were erroneously placed at 180 degrees longitude; in another case the data in the Western Hemisphere were spatially smoothed, while the data in the Eastern Hemisphere were not.

Ouch.

As Eduardo points out the implications are rather interesting, since Smerdon's findings imply that Mann's stress-testing must have been too weak to actually demonstrate what they purported to do. Fascinating stuff.

Climate contention

Eduardo Zorita thinks we might all be getting a little het up over the email in which Michael Mann says this of the Medieval Warm Period (MWP):

Phil and I have recently submitted a paper using about a dozen Northern Hemisphere records that fit this category, and many of which are available nearly [2000 years] back--I think that trying to adopt a timeframe of 2k, rather than the usual 1k, addresses a good earlier point that Peck made [with] regard to the memo, that it would be nice to try to "contain" the putative "MWP", even if we don't yet have a hemispheric mean reconstruction available that far back.

Eduardo notes the context - of creating a new temperature reconstruction - and suggests that the word "contain" must therefore mean "incorporate". I'm not so sure.

If the words are to have the meaning Eduardo suggests, then the normal English idiom would be to have a subject in the sentence. Something like:

...it would be nice to have the reconstruction contain the putative MWP...

or, since we already know wer'e talking about a temperature reconstruction:

...it would be nice to try to have it contain the putative MWP"...

Alternatively, he could have avoided referring back to the subject by using a different word altogether:

..it would be nice to try to incorporate the putative MWP...

This feature of the standard idiom is not seen in the alternative meaning of "contain", which is "restrain". Here the word "contain" doesn't need to refer back to its subject, but sits comfortably on its own.

...it would be nice to try to contain the putative MWP...

just as he said it.

Let's refer back to the original quote.

...it would be nice to try to "contain" the putative "MWP"...

Why does he use quotation marks around "contain"? There is no obvious need to do so, but could it be that this is a way of giving his readers the equivalent of a nudge and a wink? And what then is the meaning of the nudge and the wink? Is he pointing out that he has used an idiom of "restrain", but is implying that, of course, he is talking about "incorporating" the MWP? Or is it the other way round - that it really would be nice to restrain the MWP?

Who knows? Without seeing the "good point that Peck made with respect to the memo" it's hard to say, but of course there will be those who point out that Peck is Jonathan Overpeck, the man who is alleged to have written the infamous "get rid of the Medieval Warm Period " email.

The antidote to RealClimate

Climatologists Hans von Storch and Eduardo Zorita have started a new blog. Welcome to the blogosphere, gentlemen.

Is the game up for the climate junk scientists?

I posted a while back about the failure of climate scientists to archive their data or to release it on request - a scandal which has been carefully documented by Steve McIntyre's Climate Audit blog.  Another post on the same subject developed a very interesting comments thread with contributions from McIntyre and Maxine Clarke, the executive editor of Nature - one of the journals who have failed to enforce their own policies on data availability.

Over this weekend there have been a couple of developments which suggest that change is afoot. The first was a comment left by the eminent climate scientists, Hans von Storch and Eduardo Zorita, on Nature's Climate Feedback blog

Another important aspect [of McIntyre's contributions to the climate debate was] his insistence on free availability of data, for independent tests of (not only) important findings published in the literature. It is indeed a scandal that such important data sets, and their processing prior to analysis, is not open to independent scrutiny. The reluctance of institutions and journals to support such requests is disappointing.

[My emphasis] 

For two such prominent scientists leave comments of this kind on this particular blog can only be seen as a pretty stern criticism of Nature's stance on the issue, and we should certainly applaud their integrity in doing so, particularly as they seem to disagree with many of McIntyre's scientific arguments.

The second development looks to me as if it could be dynamite though. In a story entitled "Lies, all lies, but who do you tell?" the Sunday Times Science Correspondent Anjana Ahuja does a pretty good job of covering the issue of replication of scientific papers, and gives us the reactions of the management at Nature.

[Philip Campbell, editor-in-chief of Nature] is considering whether some studies, especially ones that make headlines, should be replicated before going to press.

Science operates on an assumption of honesty – raw data are rarely scrutinised by either institutions or journals, and academics are encouraged to work independently. Rogue researchers feed off this culture of trust: busy superiors and colleagues often sign off research papers and grant applications without reading them. Fame ensues and grants and citations roll in.

And so it becomes hard to “out” a suspect. Do you snitch to your head of department, for example? To your vice-chancellor? Might he or she wish to conceal an issue that could make the institution look culpable? If the person moves and you divulge your suspicions to his new employer, can you be sued?

If Nature actually go through with this and enforce the policy of replication before publication, it will be a big step forward for the integrity of science in general and of climate science in particular, although I'm sure it won't be the end of the story. For a start one might well ask the question of "who will do the replication?" Someone in the same closed clique is not going to give us the same assurance as someone who is of a diametrically different opinion. And it should also be pointed out that the new policy does not absolve scientists of the duty to make their data and code available. Different researchers may bring different criticisms to bear, and while it is obviously impractical to demand that everyone should have a shot at a paper pre-publication, it remains vital that they are able to do so after the event.

But all this notwithstanding it looks as though there may have been a welcome shift in the position of Nature on the issue. I'm sure everyone who cares about science, whether believers in global warming or not, will recognise that this can only help the search for the truth. Let's hope that this embarrasses the other culprits into making similar changes.

And while we're about it, we might also note that pretty much the whole story has been played out on blogs. Well done the blogosphere.