Fair-ish and Balanced-ish
Tuesday, December 16, 2003
Read The References
Some interesting points are being made on usenet over McIntyre and McKitrick's "audit" of Michael Mann's 1998 temperature reconstruction.
Some of the public questions that M&M have asked is why certain data series were truncated.
What they didn't do is try to track down the scientific papers that were associated with each data series and read see if the reason is there.
Fortunately, Josh Halpern has looked up the original papers that came with two of the truncated series.
The first series involves the Central England historical record. M&M ask why Mann uses 1730 - 1987 AD, when the series starts at 1659 AD.
A better question would be, why didn't M&M read up on how the data series was made up. Had they done this, then they would be aware that up until 1722 AD, the various records which make up this data were non-overlapping. Additionally it seems that better instrumentation was used post 1727 AD. So Mann simply removed dodgy data.
The next truncated data series is the Central Europe historical record. M&M ask why Mann's reconstruction starts in 1550 AD, when the record starts in 1525 AD?
They should have read the references. Had they done this, they would have seen the following "The evidence increases in volume, density and diversity over time. For the period 1525-1549 the entries originate mainly from chronicles and annals. Accordingly, weather sequences are mainly described at a seasonal level; information is missing for 43% of the months and the emphasis is on anomalous rather than ordinary weather. In the second period 1550-1658 monthly data from weather diaries and personal papers are abundant....."
Once again, Mann used the more accurate data.
M&M are trying to pass themselves of as auditors. However, if they want to pass technical judgment on a scientific work, would it not be completely unreasonable for them to read up on the scientific literature before they go public?
Anyway, the usenet thread is here.