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.