Climate cuttings 14
Nov 27, 2007
Bishop Hill in Climate: Cuttings

There's been no shortage of action on the climate front in recent weeks. In fact, the only reason I haven't been posting more often is the sheer effort of trying to stay abreast of everything as well as doing the day-job. Here then, is the climate news you may have missed.

We know that when you are making a reconstruction of the historic temperature from tree rings, you shouldn't use bristlecone pines (BCPs). This was the advice of the US National Academy of Sciences who observed that these species are thought to be prone to CO2 fertilisation - which is to say that increased growth might be due to more CO2 in the air, rather than temperature. Of course the IPCC doesn't care about this and uses BCPs all the time, most notoriously in the "Hockey Stick" graph. Now, a new paper from Craig Loehle finds that if you don't use any tree rings in your reconstruction, you don't get a hockey stick at all - in fact the medieval warm period looks warmer than the present. This is upsetting to "warmongers" who claim that the MWP was a local phenomenon.

Because of this the Loehle paper was attacked or ignored. Julien Emile-Geay, a colleague of hockey stick manufacturer, Michael Mann, gave a bravura performance in a thread at Climate Audit, in which he called the Loehle paper "pseudoscience" because, amongst other things, it didn't calculate error bounds. He become rather bashful when it was pointed out to him that none of his colleagues did this either. Nobody seemed to be able to explain how error bounds for this kind of reconstruction should be calculated. Which is odd, when you think about the idea that the science is apparently "settled".

Loehle's approach to calculating a global temperature turns out to have been rather unique. The proxies he used were each calibrated against local temperature to give a reconstructed local temperature record. Then the reconstructed temperatures for each locale were averaged to give a global temperature. This is very different to the way this kind of thing has been done in the wacky world of hockey stick climate science. Here, proxies of different kinds, some calibrated, some not, are aggregated and then some kind of a global temperature signal is looked for by statistical means. The idea is that proxies will correlate in some way with temperatures elsewhere in the world by means of something called "teleconnections". This seems, shall we say, unconvincing.

One of the proxies used in a recent temperature reconstruction was rainfall records. If you're wondering, these are thought to teleconnect to temperature, so you can look for a temperature signal in there.  This sounds daft enough, but when you learn that the coordinates of the locations used were not correctly aligned with the temperature data, so that, for example, the rainfall in Philadelphia was compared to the temperature in Bombay, it sounds truly crazy. However the really amazing, fall-off-your-chair laughing bit, is that this error had also been observed in one of the author's previous papers, and that he had had his gaffe pointed out to him then! And the author? Hockey stick guy, Michael Mann! Who else?

Meanwhile a recent PhD thesis raises important questions about some of the bristlecone pine records. The hockey stick graph is driven by a surge in growth in bristlecone pine trees in the latter half of the twentieth century. One of the most important such records is the Graybill chronology from Sheep Mountain. The new thesis updates these records, but shows none of the growth surge that was previously reported. Unfortunately, no attempt was made to reconcile the two sets of records, but this would appear to kill the hockey stick stone dead. Not that this will bother the IPCC who will, no doubt, continue to use it.

If you've seen Al Gore's "An Inconvenient Truth", you will remember the long, long graph with the surge in temperatures at the end, which was incontrovertible evidence that the Earth is warming in an unprecedented fashion... apparently. Gore claimed that the graph was from ice core records and that it therefore supported the hockey stick and refuted its critics. Except it wasn't from ice cores at all, it was just a reprint of the hockey stick itself. Yes folks, he made it up.

In the last edition of Climate Cuttings, I reported Tim Worstall's observation that the global warming panic should recede, now that the global economy seems to be following the Stern report's "warmer but richer" scenario, rather than the more unpleasant poorer one. Now Tim has also reported that the whole crisis should be over in a couple of decades because of the rapidly falling price of solar cells. The end of the carbon economy is is sight. Don't do something - stand there!

Reports that sea level will rise when the Greenland ice sheet melts are less certain than previously advertised. The glaciers are sitting in a bowl of rock.  It has been demonstrated that James Hansen at NASA knew this, but made his scaremongering claims of sea level rise anyway.

According to satellite records, October was the second coolest month on record

There is no link between global warming and typhoon activity. 

Northern latitudes should be warming fastest, according to global warming theory. Why then is there no warming apparent in the Baltic?

Global warming might thin cirrus clouds and release all the extra heat, according to a new paper.

And that's it for this time. Thanks to those people who have suggested that I get off my backside and do some more blogging. I will try to oblige, time permitting.

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