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A 400-Year Temperature History of Kunashir Island, Northwest Pacific
Reference
Jacoby, G., Solomina, O., Frank, D., Eremenko, N. and D'Arrigo, R.  2004.  Kunashir (Kuriles) oak 400-year reconstruction of temperature and relation to the Pacific Decadal Oscillation.  Palaeogeography, Palaeoclimatology, Palaeoecology 209: 303-311.

Background
Kunashir is the southernmost large island in the Kurile Island chain belonging to Russia. Located between the Sea of Okhotsk and the northwest Pacific Ocean, the authors say that "temperatures on the island are strongly influenced by the surrounding sea-surface temperatures."

What was done
Jacoby et al. extracted cores from century-old oaks (Quercus crispula) growing on Kunashir Island within one km of the Pacific Ocean and developed them into a four-century tree-ring width index series that was shown to correlate strongly with Island summer (June-September) air temperature.

What was learned
The authors report that "the recorded temperature data and the tree-ring data show similar correlation patterns with sea-surface temperatures (SSTs) of the North Pacific."  More specifically, they find that "the tree-ring series explains more than 33% of the variance of the July-September Pacific Decadal Oscillation and has similar spectral properties, further supporting the concept of multidecadal variation or shifts in North Pacific climate, for four centuries."

Of even more interest to us is the fact that the Kunashir June-September mean maximum temperature reconstruction shows no long-term trend (neither cooling nor warming) over the entire period from 1600 to 2000, nor does it show any net temperature change over the 20th century.  Also of note, the peak warmth of the last hundred years occurs right at the mid-century mark, after which temperatures decrease considerably to end up right about where they started the century.

What it means
The long-term reconstructed temperature history of Kunashir Island bears absolutely no resemblance to the IPCC-endorsed "hockeystick" temperature record of Mann et al. (1998, 1999), which boasts a temperature increase from 1910 to the end of the record that its creators describe as being unprecedented over the entire past millennium.  With Kunashir temperatures being "strongly influenced by the surrounding sea-surface temperatures," as Jacoby et al. say they are, we wonder how much more of the Pacific Ocean likewise fails to follow the politically-correct temperature trend, while marching unfalteringly to the rhythmic beat of the Pacific Decadal Oscillation.  Being faithful to the latter, is it not strange that Kunashir temperatures are unfaithful to the former?  Perhaps not, if the former is unfaithful to reality.

References
Mann, M.E., Bradley, R.S. and Hughes, M.K.  1998.  Global-scale temperature patterns and climate forcing over the past six centuries.  Nature 392: 779-787.

Mann, M.E., Bradley, R.S. and Hughes, M.K.  1999.  Northern Hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations.  Geophysical Research Letters 26: 759-762.


Reviewed 1 September 2004