A new paper - 'A Model-Based Approach to Climate Reconstruction Using Tree-Ring Data'

Authors - Matthew R. Schofield, Richard J. Barkerb Andrew Gelman, Edward R. Cook & Keith R. Briffa

Conclusions - 'We show that minor changes in model specification can have little effect on model fit but lead to large changes in the predictions. In particular, the periods of relatively warmer and cooler temperatures are robust between models, but the magnitude of the resulting temperatures are highly model dependent.'

http://www.tandfonline.com/doi/abs/10.1080/01621459.2015.1110524

'They found that competing models fit the Scots Pine data equally well but still led to substantially different predictions of historical temperature due to the differing assumptions underlying each model.

While the periods of relatively warmer and cooler temperatures were robust between models, the magnitude of the resulting temperatures was highly dependent on the model being used.

This suggests that there is less certainty than implied by a reconstruction developed using any one set of assumptions.'

http://www.sciencedaily.com/releases/2016/01/160127101524.htm

The link to Jones et al 1998? Jones et al made extensive use of the Briffa (1996 and  1998) and Mann (1998 and 1999)  papers in dendrochronology to arrive at their conclusions.

https://www.st-andrews.ac.uk/~rjsw/papers/Jones-etal-1999.pdf

The link to NOAA?  NOAA use Jones et al 1999 as the reason for adjusting global temperatures.

https://www.ncdc.noaa.gov/sotc/global/199713

So where to from here. It appears that the early Briffa papers on dendrochronology are not robust. That would necessarily throw doubt onto Jones et al, and ultimately the NOAA temperature adjustments.

I presume that you mean dendroclimatology as opposed to the use of tree ring data to find the specific age of archaeological artifacts (dendrochronology) .

It's a fascinating subject, but it's subject to all kinds of interferences, not the least of which was the atmospheric nuclear tests.  One of my best school mates became a dendrochronologist and labs such as the LTRR in Phoenix Arizona also carry out dendroclimatology research.  It's probably a second or third best temperature proxy, in the same league as lacustrine varve studies using Oxygen isotopes.   

The main problem is confounding effects such as localised droughts, lack of geographical coverage, nutrient deficiency, pest infestation etc.
The use of MXD data is superior to ring width, but still has similar limitations.

A Scots Pine study is obviously highly localised.

Why are you bringing up a 1998 paper? It's good ancient history I guess, but little else.

lee wrote on Jan 31^st, 2016 at 5:40pm:


Are you changing the subject for any reason?

John_Taverner wrote on Jan 31^st, 2016 at 5:45pm:



Nope, but you seem to be. \\Scots Pine -

'Scots pine (Pinus sylvestris L.) is a species of pine that is native to Eurasia, ranging from Western Europe to Eastern Siberia, south to the Caucasus Mountains and Anatolia, and north to well inside the Arctic Circle in Scandinavia. In the north of its range, it occurs from sea level to 1,000 m, while in the south of its range it is a high altitude mountain tree, growing at 1,200–2,600 metres (3,900–8,500 ft) altitude'
https://en.wikipedia.org/wiki/Scots_pine

Not so localised.

lee wrote on Jan 31^st, 2016 at 5:46pm:


Which dataset is that? 

lee wrote on Jan 31^st, 2016 at 3:42pm:


No revelations in this paper.

Sensitivity to model type and assumptions made is a well known phenomena in Science.

Isn't it so Lucky lee, that scientists don't EXCLUSIVELY rely on tree ring data to map out the Chronology of the Universe as we know it?

apologise for deceiving and self ban

This is probably more relevant (note the Swedish Subtitles) :

John_Taverner wrote on Jan 31^st, 2016 at 6:03pm:



The one used for hottest year evah claims.

lee wrote on Jan 31^st, 2016 at 6:16pm:


It's called an abstract. On the same abstract:

using an example case of Scots pine from Torneträsk, Sweden

It's very relevant if you are a Moose or an interesting  furry animal from Sweden.

Hm, how good is the Yamal data, if you are going for how limited scope the new paper is.

John_Taverner wrote on Jan 31^st, 2016 at 6:41pm:


We have perfectly good instrumental data. That's why the liks of NOAA and our own BoM have decided on 'homogenisation' so as to eliminate the inconvenient truths of this 'perfectly good instrumental data'. The argo Buoys recorded sea temperature for many may years, but NOAA rejected that data and instead used (no joke), temperatures from buckets taken by passing ships.

So why do all these things? TO GET THE ANSWER YOU WANT, not the actual answers.

John_Taverner wrote on Jan 31^st, 2016 at 6:41pm:



Dear Breathless, How about Marcott?

'One author, Jeremy Shakun (currently at Harvard) weighed in via Skype for Dot Earth. When more questions came in, the group of authors wrote that they would respond more completely to questions about the work and now they have done so, on the RealClimate blog. Here’s a short excerpt and link to the rest:

    Q.

    What do paleotemperature reconstructions show about the temperature of the last 100 years?
    A.

    Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions. Our primary conclusions are based on a comparison of the longer term paleotemperature changes from our reconstruction with the well-documented temperature changes that have occurred over the last century, as documented by the instrumental record. Although not part of our study, high-resolution paleoclimate data from the past ~130 years have been compiled from various geological archives, and confirm the general features of warming trend over this time interval.'

http://dotearth.blogs.nytimes.com/2013/03/31/fresh-thoughts-from-authors-of-a-pa...

And of course Mann did precisely that, marrying Dendro to "perfectly good instrumental data" to show it was only 20th century warming.

lee wrote on Jan 31^st, 2016 at 8:05pm:


I'll ask again. Do you think that  paleoclimate reconstructions have any bearing on instrumental datasets ?

Are they used in NASA GISTEMP?
Are they  used in NOAA MLOST?
Are they  used in Hadley Hadcrut datasets?

Quote:


I think you are confused by reading too many blogs. Answer my first question.

lee wrote on Feb 1^st, 2016 at 10:26am:


I asked first. For some reason you are avoiding the question.

lee wrote on Feb 1^st, 2016 at 3:16pm:


I find it incomprehensible that anyone with any intellectual honesty would adjust accurate temperature readings in line with the least accurate measuring tool available - tree rings.

lee wrote on Feb 1^st, 2016 at 3:27pm:


Why would you adjust them at all? Are our historical temperature records not good enough and if so, how could we possibly know that without reference to a MORE ACCURATE source - which doesn't exist.

mariacostel wrote on Feb 1^st, 2016 at 3:47pm:


What is this? Dumb and dumber?  Tree ring data is terrestrial. Ship engine intakes is not.

mariacostel wrote on Feb 1^st, 2016 at 5:42pm:


Yeah? They don't.  They would be pulled up pretty quickly if they did. There is no conspiracy.

There needs to be some processing to get consistency within datasets, but it's all highly transparent.

Taking Lee's example of marine temperatures, I think he's referring to this paper:

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00006.1

and this paper:

http://science.sciencemag.org/content/348/6242/1469.full

- which are complementary.

I'll give him a chance to actually read them rather than take the second hand bastardised critique based on supplementary materials. 

lee wrote on Feb 1^st, 2016 at 7:28pm:


I've read the whole paper and evaluated it for myself.

If you have actually read it now, what is the net effect of the corrections? (the biggest effect being pre 1940). Did they 1. Increase the reported overall warming trend or 2. Decrease the reported overall warming trend?


Quote:


Here you're talking about paleoclimate reconstructions again, right? Explain to me the relevance again.

You seem to have a liking for very old papers.

lee wrote on Feb 1^st, 2016 at 9:39pm:


Incorrect.

lee wrote on Feb 2^nd, 2016 at 1:57pm:


You still haven't done any reading of the papers that contributed to ERSST v4. We can talk about accuracy and precision after you get the basics right.

I'm trying to see if you can draw your own conclusions from the papers, or even understand them outside the very narrow context of  Wattsup's article.

Why adjust the temperature data records and along the way NOT inform the public that this has happened.

Anthropogenic Global Warming equals a pseudo science with no legs to stand on.