Tree Ring Study

15 Jan 2011

At there is a post on an article in New Scientist of January 14th commenting on a paper by Buntgen et al that was actually published in Science (DOI: 10.1126/science.1197175.htm ). The comments at the various blogs where this has appeared have largely been negative as they are sceptical of tree rings having the ability to record temperatures - as a result of tree ring proxies used by the likes of Michael Mann, Keith Briffa etc. However, the study does actually pinpoint phases in climate that are not controversial. For example, from AD250-600 the climate is said to have flipped -which is the kind of thing Steve Mitchell has been saying, as well as Dick Gagel (regards the Netherlands). Climate was in general up and down in this period - not universally bad. As the study was done on a decade by decade basis some blocks of ten years were dry and cool and others warm and wet - or that is the inference drawn. This climate change coincided with the collapse of the western Roman Empire and the migration of barbarian tribes. Likewise, they note that very wet weather was a feature of the period leading up to the Black Death.

Tree rings from the Alps were used to reconstruct climate over the past 2500 years - and the same story appears in Der Speigel where it was picked up by Pierre Gosselin at January 14th. Gosselin claims the study supports the sceptic position in that warm periods coincide with flourishing societies whereas in contrast, during wet and cold periods all kinds of things started to go wrong.

In addition, the same story can be found at where it says that it concerns central European temperature and precipitation trends, the ups and downs in the life of trees. The usual nod to AGW is included in the paper, a sop it would seem to the system - to ensure publication and acceptance by the peer review method.