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Excuse Files: Arctic treemometers measure sunlight too

The Satirical Times

Mother Nature has issued a disguised voluntary recall notice for Arctic Treemometers. Sold as a way of measuring temperatures over the last two millennium, they turned out to fail frequently, even going against trends in most other thermometers in the last half century. The flaw has been quietly recognized for years, but is rarely mentioned in polite circles.

Critics wonder why it took Mother Nature so long to issue the recall and why it is so qualified and partial. They point out that these safety warnings only seem to appear when product salesmen are also offering a repair kit for sale too.

In this case Stine and Huybers tell us they can fix the “divergence” problem with treemometers by considering incoming light. Treemometers are failing, they say, because of global dimming and inconvenient volcanoes. As long as sunlight reaches trees the treemometers work. (Critics dryly reply that it’s hardly news that sunlight affects tree growth, and that they never bought the tree-ring data in any case.)

Meanwhile Mann-made Treemometers Inc issued a statement in 4-point Roman Half-Uncial script at 3am saying that their Treemometers are as accurate as ever in all locations where cloud cover, dust and rainfall doesn’t deviate more than 5% from the seasonal mean. They unconditionally guarantee their reliability “in all situations and centuries where cloud cover data is available, and emails about data are not”.

One stock analyst predicted that “One day, most of the Western World will want a refund”.

Arctic study sheds light on tree-ring divergence problem: Changes in light intensity may impact density of tree rings

[Science Daily]
New research has found that changes in tree-ring density in the Arctic may be evidence of changes in light intensity during the trees’ growth. The finding has direct implications for the tree-ring ‘divergence problem,’ in which the density of tree rings in recent decades has not kept pace with increases in temperature, as expected.

The finding has direct implications for the tree-ring “divergence problem,” a phenomenon that has received considerable media attention but has been widely misinterpreted, said Stine, an assistant professor of Earth & climate sciences.

Tree rings consist of a low density ring, which forms early in the growing season, and a high density ring that forms late in the growing season. In colder parts of the world, the dense latewood rings tend to be denser during warm years. Temperature records inferred from Arctic tree rings do a good job of tracking temperature up until the 1960s, but subsequent Arctic tree-ring densities did not keep pace with increases in temperature, a discrepancy that is called the divergence problem.

The divergence issue was the reason given for “hiding the decline”. If 1980 model treemometers don’t work, the consumer is left to wonder why 1480 treemometers would be any better.


A. R. StineĀ  & P. Huybers (2014) Arctic tree rings as recorders of variations in light availability, Nature Communications, 5, Article number: 3836 doi:10.1038/ncomms4836

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