Quote Originally Posted by Boon Mee
New Study: Two Thousand Years of Northern European Summer Temperatures Show a Downward Trend | Watts Up With That?
The first thing that concerns me about Boons article is that it comes from Whatsupwiththat, a known oil funded denialist mouthpiece that is not to be trusted or considered in any way reliable for information on climate change. That being said they are reporting on an article in the Journal of Quaternary Science which is an accredited peer reviewed journal. The implied interpretation that the article somehow proves global warming is false is the denialist webpages perspective not the authors of the article. They are merely concerned with the scientific results of a new method of dendrochronology in conifer trees.

The article gives mean temperature shifts for a regional climate, northern Europe, a region with particular weather systems influenced by the cold jet stream air current that comes off Greenland and the Arctic. A region that in recent years has suffered extreme weather events at both ends of the spectrum because of global climate change. Using data from one small region of a continental land mass and applying it to the entire globe is incorrect. I have no doubt that if there has been a slow decrease in the temperature of Northern Europe then those temperatures are well documented by both historical sources and modern day instrumentation, and that that data is included in the overall calculations of the global mean temperature. How could it not be given that Europe is the oldest settled land area with archival records of any thoroughness and the birth place of modern science. I know that climate and temperature records were kept with sometimes daily accuracy form the middle ages on and reconstructions of these are incorporated into studies of the paleoclimate of Europe. A 0.3C drop across northern Europe does not directly correspond to a drop in mean temperature globally.

What would it take for this study to be representative of global mean temperature?

Replicate it across the globe including all the strata of the oceans.

What's that? There are no conifer trees or indeed trees of any kind in the oceans, and there are vast regions of the continents that have never had trees or continual tree coverage.

Well that's that idea shot down then isn't it.