Bias justified claims NIWARichard Treadgold | July 28, 2012
So is it?
Let’s start to crack this open. Since the judge hasn’t delivered his decision we’ll be careful, but I’m advised we can discuss it freely as long as we don’t insult the judge (or NIWA’s scientists, for that matter). [ADDENDUM: Or attempt to influence the judge's decision.]
There are several incongruous aspects of NIWA’s 7SS adjustments that have always mystified Coalition* members:
- The whole warming trend of about 1.0°C/century is brought about by pre-1945 downward adjustments, which are curiously linear (see graphs).
- Although the site changes causing them are random, over 90% of the adjustments move in the same direction; they do not balance out as the literature suggests they should.
- The 7SS adjusted warming trend is inconsistent with the official temperature series published in 1867 and 1920; these showed that the nationally-averaged temperatures recorded back then were just as high as they are now.
- The largest New Zealand warming occurred during the half-century 1909-59, with the second highest being 1859-1909. The period 1959-2009 – which coincides with IPCC-reported global warming – shows the smallest trend (only 0.4°C/century).
NIWA’s statement of defence finally revealed why none of these anomalies worried its scientists. The early site changes were NOT random, it claimed, but reflected a systematic migration from warmer to cooler sites. In later evidence, Dr David Wratt elaborated his theory that economic pressures might have led the Met Service to move out of the warm centres of town to cheaper land on the outskirts.
A theory that nobody’s heard of…
This hypothesis came with bells and whistles. People built their settlements at the warmest spots and set up their weather stations close to their homes. But, as towns expanded, they were taken over by a money-strapped government agency, which saw the opportunity to cash up high-value land. The stations were moved to less hospitable and colder environments, where land was cheaper – particularly in the earlier part of the 20th century.
These systematic warm-to-cold relocations of the seven stations were done so smoothly, avoiding unnatural jumps or discontinuities, that the temperature readings revealed only a mild warming of about 0.3°C per century. The perfectly-coordinated system of nation-wide station moves (apparently) completely disguised the fact that the country’s temperatures were actually rising very strongly under the influence of global warming.
NIWA never mentioned this fake skew until the Coalition detected it during their audit last year. But the hidden built-in bias had been unmasked already by Salinger’s 1981 thesis, which adjusted the historical records to offset it.
“I accept [Professor] Carter’s statement that the adjustments made in the NIWA 7SS Review do not balance out,” says Dr Wratt’s affidavit. “But this causes me no difficulty as a professional climate scientist, for the reasons I have outlined in paragraphs 218, 221, 222, and 223.”
Those paragraphs, and many more, expanded upon NIWA’s socio-economic insights regarding the systematic migration of early-20th-century weather stations.
The plaintiff (the Coalition) complained that there was no evidence to support this theory. It said that economic history was not listed amongst NIWA’s numerous claimed competencies, and the hypothesis did not show up in the literature or the metadata or anywhere else.
…and is contradicted by NIWA’s own work…
Then the plaintiff’s counsel turned to NIWA’s Review, which shows detailed maps of the various sites making up the 7SS. In Auckland, the Domain site moved to Princes St and then to Albert Park, cementing itself in the inner city rather than moving away. In Dunedin, the sites moved from the Leith Valley towards the centre of town. And so forth…
Terry Sissons noted that the Salinger thesis had arrived at the opposite conclusion, believing that stations in the middle of town had grown warmer over the years as a result of the urban heat island (UHI) effect. The stations should have been moved, but this seldom happened.
When the defence replied, the dogmatism of the affidavit was notably absent. It seemed Dr Wratt was merely trying to understand why 9 out of 10 adjustments might have moved in the same direction.
The key point, defence counsel said, was that the plaintiff hadn’t proved that NIWA was labouring under this mistake back in 1999 when the 7SS was first published.
…but now it’s solved – UHI was hiding our global warming
Well… if the systematic migration hypothesis is a new invention, why does NIWA plead that it justified the decisions taken back in 1999?
And if Salinger & co didn’t come up with this speculation at the time, what did they believe? Did they really think that random site changes should be fixed by non-random adjustments? Did they assume that all previous attempts at nationally-averaged records were flawed?
Or was this just confirmation bias of the type psychologists say is inevitable in the absence of checks and balances?
* NZ Climate Science Coalition
What do I mean by UHI “hiding our global warming”? The idea is somewhat illogical, for how can UHI warming hide global warming? Well, the fact is that UHI has made it difficult to identify the magnitude of both UHI and global warming at weather stations sited in urban areas. With repeated outward moves, a rising trend from any cause is wholly or partly diminished by the cooler temperatures in the new location. If temperatures were rising in response to both UHI and global warming, calculating the adjustments to correct the readings becomes problematic.
With NIWA’s adjustments to the 7SS (which they claim were made by Salinger) now shown to be highly biased towards warming, and which are apparently corroborated by their recent reconstruction, they must explain why they have still made no adjustments for UHI, yet they claim the UHI effect is the cause of the bias. Certainly, while making adjustments because of the UHI effect, they “discovered” a strong global warming effect.
Do we believe them?