Cook, E.R., Palmer, J.G., Cook, B.I., Hogg, A. and D'Arrigo, R.D. 2002. A multi-millennial palaeoclimatic resource from Lagarostrobos colensoi tree-rings at Oroko Swamp, New Zealand. Global and Planetary Change 33: 209-220.
What was done
The authors report the results of the first millennium-length tree ring chronology for New Zealand. Derived from long-lived silver pine trees (Lagarostobos colensoi) in the Oroko Swamp on the West Coast of South Island (43°14'S, 170°17'E, 110m), the chronology provides a history of Austral summer temperatures since 816 A.D. The period of greatest confidence in the record begins at 1200 and ends at 1957, after which the instrumental record is used to extend the temperature history up to 1999.
What was learned
No long-term trend was evident in the tree ring-derived Austral summer temperature record over the entire length of the study, including the overlapping instrumental portion of the record that extends from 1866 to 1999. Hence, neither the tree-ring data nor the actual temperature measurements from the area provide any support whatsoever for the climate-alarmist claim of "unprecedented" warming over the last hundred years. In fact, say the authors, "the reconstruction indicates that there have been several periods of above and below average temperature that have not been experienced in the 20th century," indicative of the fact that New Zealand climate was much less variable over the last century than it was over the prior 700 years.
What it means
With absolutely no sign of anything unusual in terms of either temperature trends or variability over the 20th century in this record from "down under," there is little wonder that that hemisphere's John Daly is "still waiting for greenhouse" (see his website at www.john-daly.com).
Reviewed 18 September 2002