How Important is Yamal

Recently there has been a bit of two-way extremism in blogland claiming that hockey sticks that depend on Yamal (don’t matter). A second group of people who are aware of the large quantity of serious flaws in climate science are ready at every new discovery to chuck the whole thing. Unfortunately for those who just want clear answers, neither of these is the case. The following studies are affected to some undetermined degree by Yamal, Quote by Steve McIntyre.

In summary, the apparent problems with Briffa’s Yamal series impact multiple other studies:
Briffa 2000, Mann and Jones 2003 (used in the recent UNEP graphic), Mann et al (EOS 2003), Jones and Mann 2004, Osborn and Briffa 2006, D’Arrigo et al 2006, Hegerl et al 2007, Kaufman et al 2009 (and of course, Briffa et al 2008).

It’s interesting to note that so many popular hockey stick reconstructions employ Yamal. On the other hand AGW advocates are far to quick to say reconstructions don’t matter either – Gavin Schmidt and Michael Mann at Real Climate’s latest, where several hockey sticks with even more severe problems are presented as supporting evidence of the Robustness of the Yamal paper group. Unfortunately for them, it cannot be denied, the Yamal find is a serious issue in climatoloty. Unfortunately for those of us at the mercy of government policy based on these papers, problems in climate science like this are NOT unprecedented.

This is a guest post by John F. Pittman which endeavors to explain the import of proxy temperature recontsructions in the context of the IPCC AR4 report.

Jeff Id

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Why Reconstructions Matter

Wahl and Amman Hockey Stick. Besides the obvious Nike swish popularity, and clear visual impact, there are scientific issues regarding the hockey stick graphs. --- Jeff Id

Introduction:

 

The AGW blogosphere is busily proclaiming that the recent problems with Briffa’s Yamal do not matter. With the debunking of the Mann MBH9x by M&M0x, and by the NAS and Wegman reports, reconstructions began using the Yamal chronologies. Despite the claim by AGW proponents, it does matter. We start not at the chapters on reconstructions, but rather with understanding and attributing climate change.

Section I

 

Understanding the Basic Claim

From IPCC AR4 WG1 Chapter 9 p665.

Understanding and Attributing

Climate Change

Greenhouse gas forcing has very likely caused most of the observed global warming over the last 50 years. This conclusion takes into account observational and forcing uncertainty, and the possibility that the response to solar forcing could be underestimated by climate models. It is also robust to the use of different climate models, different methods for estimating the responses to external forcing and variations in the analysis technique. … Anthropogenic influence has been detected in every continent except Antarctica (which has insufficient observational coverage to make an assessment), and in some sub-continental land areas. The ability of coupled climate models to simulate the temperature evolution on continental scales and the detection of anthropogenic effects on each of six continents provides stronger evidence of human influence on the global climate than was available at the time of the TAR. No climate model that has used natural forcing only has reproduced the observed global mean warming trend or the continental mean warming trends in all individual continents (except Antarctica) over the second half of the 20th century.

Break Time

I need a break from blogland. There are a dozen things I could write about and perhaps tomorrow I’ll change my mind. In the meantime, if someone has something interesting to post, send an email.

So I left a comment on Real Climate phrased simply like this:

Do you have any specific criticisms of the tree ring data used by Steve McIntyre or do you have any criticisms of the methods he used?

Clipped, snipped and trashed. In fact there is no mention of Jeff Id or tAV on their thread in any of the comments. hahaha. It’s like anti-fame, Michael Moore in a republican primary. Dunno why? hehe.

I’ve been playing with Yamal today, maybe I’ll change my mind about blogging tomorrow.

Gridded Daily Sea Ice – NSIDC

I’ve been working on improving the noise rejection of the sea ice area and anomaly from the NSIDC gridded data. These plots are created by summation of the gridded satellite sea ice concentration data the following table is up to date as of 2008

Platform and Instrument	Time Period
Nimbus-7 SMMR	26 October 1978 through 20 August 1987
DMSP-F8 SSM/I	9 July 1987 through 31 December 1991
DMSP-F11 SSM/I	3 December 1991 through 30 September 1995
DMSP-F13 SSM/I	3 May 1995 through the March 26 2008
DMSP-F17 SSM/I	26 Mar 2008 through present

This table is not the official table presented by the NSIDC as I have added the end point for F13 and the beginning point for NOAA-17. I should note that for a time in 2008 overlapping data is presented for both F13 and F17.

My plots still aren’t perfect matches to the NSIDC or Cryosphere but they are very close. Some reasons for differences include:

• No access to final processing routines used to blend and filter daily trends.
• The anomaly for these plots is computed over the whole length of the dataset whereas other scientific institutions limit the anomaly calculation period to different fixed sets of years.
• Filtering differences
• Differences in methods for locating and removing bad points from the near real time data

Either way, differences in the results are quite small and the net trends and absolute magnitude are close. Thanks to the NSIDC for making the data available, their openness gives me an improved comfort in the quality and completeness of the work done by this agency.

You Lie

Roger Pielke Jr. out vents the Air Vent- hard to do on the slowest of days.  Gavin Schmidt deserves this though.  Thanks to Paul for the link:

Hockey Stick Gets Personal: Lies from Real Climate

RC Off the Deep End

There are two responses by Gavin which were left on RC that I cannot get past.  He is stooping to making up crimes now for Steve McIntyre’s apparently pending trial.  The crime of propagating slander.  Steve McIntyre has them so wound up that they cannot make a scientific argument to discount why his tree rings are incorrect and Briffa’s are.  In the process they’ve created some of the most fantastic irony I’ve ever read in print.

From Gavin Schmidt to a single commentor True skeptic:

I’m sorry but what’s required is specific quotes, with URLs of course, to refute nonsense immediately. Replies like yours just feed nonsense claims of “snark”.

Response: Fair enough, so here goes (a couple of allied quotes as well): 1) “In my opinion, the uniformly high age of the CRU12 relative to the Schweingruber population is suggestive of selection”, 2) “It is highly possible and even probable that the CRU selection is derived from a prior selection of old trees”, 3) “I do not believe that they constitute a complete population of recent cores. As a result, I believe that the archive is suspect.”,4) (Ross McKitrick) “But it appears that they weren’t randomly selected.”, 5) (Anthony Watts) “appears to have been the result of hand selected trees”, – gavin]

How to Read RC

Gavin apparently put up a response to Steve McIntyre now as well.  I almost never check over at Real Climate but always know what’s happening from other peoples comments.  Their post is very silly from a scientific perspective but will read well for their attack dogs.    I’m becoming pretty familiar with these reconstructions and methods for an aeronautical engineer and I’m not really interested in defending Steve McIntyre but ya know, sometimes it needs to be said.

So for those who don’t have a year of working code on paleo papers under your belt, this is how the RC post reads to me:

Briffa Responds

I’m certain we’ll be hearing more on this today.  This post is copied from a link here.It is a comment from Keith Briffa regarding Steve McIntyre’s recent findings on tree ring data.  The most interesting thing he said was that the Yamal data was NOT pre-sorted according to climate data.  He appears to take offense at the suggestion even though it is standard practice in much of Mannian paleoclimatology.

In addition, he claims his data is the same as the H & S data with different standardizations.  Paper is here. I don’t know a darn thing about corridor standardization but I can infer some detail after my recent study of the Briffa standardization.  On the surface, it seems impossible that standardization might flatten the data to the extent expressed in H & S but we’ll have to wait and see.  There are some points in here which seem to misrepresent reality however, and lead me to wonder what will be said next. i.e. He offers no justification for excluding the original data

Sounds kind of familiar doesn’t it.

I also wonder what he means by unusually high summer temps, there isn’t anything in McIntyre’s statement supporting or denying anything about temperature (my bold in his comment).  Not one comment I recall from Steve. And I’ve seen the temp graphs and there doesn’t seem to be any evidence of unusually high summer temps either.  It’s a distraction which is difficult for me to grasp in the context of reality, as though it is meant to discredit McIntyre while supporting the unprecedentedness of global warming.

UPDATE:

Steve’s reply to Briffa.

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The Yamal ring-width chronology of Briffa (2000)

My attention has been drawn to a comment by Steve McIntyre on the Climate Audit website relating to the pattern of radial tree growth displayed in the ring-width chronology “Yamal” that I first published in Briffa (2000). The substantive implication of McIntyre’s comment (made explicitly in subsequent postings by others) is that the recent data that make up this chronology (i.e. the ring-width measurements from living trees) were purposely selected by me from among a larger available data set, specifically because they exhibited recent growth increases.