Comment On Tree Ring Proxy Data and Thermometer Type Surface Temperature Anomalies And Trends

There was an interesting conclusion in a New York Times article on the relationship between tree ring proxy temperature trend analyses and thermometer type measures of temperature anomalies and trends.  The article is

British Panel Clears Scientists  by Justin Gillis published on July 7, 2010

The relevant text is on page 2 it is written

“But they were dogged by a problem: Since around 1960, for mysterious reasons, trees have stopped responding to temperature increases in the same way they apparently did in previous centuries. If plotted on a chart, tree rings from 1960 forward appear to show declining temperatures, something that scientists know from thermometer readings is not accurate.”

There are, however, problems with this conclusion. Since the thermometers are not coincident in location with the tree ring data (in the same local area), it would not be surprising that they are different. Indeed, this is yet another example that implies unresolved biases and uncertainties in the surface temperature thermometer type data as we discussed in several of our papers (see and see), as the thermometers are measuring elsewhere then where the proxy tree data is obtained.  This obvious issue has been ignored in the assessment of this so-called divergence between the two methods to evaluate temperature anomalies and trends.

It is possible, of course, that the trees are responding differently due to the biogeochemical effect of added carbon dioxide and/or nitrogen deposition. Nonetheless, to accept the thermometer record as the more robust measurement of spatial representative temperatures is premature.

I have discussed this issue further in the posts

Comments On The Tree Ring Proxy and Thermometer Surface Temperature Trend Data

December 2007 Session ‘The “Divergence Problem’ In Northern Forests

A New Paper On The Differences Between Recent Proxy Temperature And In-Situ Near-Surface Air Temperatures

Comments Off on Comment On Tree Ring Proxy Data and Thermometer Type Surface Temperature Anomalies And Trends

Filed under Climate Science Misconceptions

Comments are closed.