Open Review

This section is devoted to discussion of issues arising from Still Waiting for Greenhouse. Opinions expressed in these articles do not necessarily represent those of John Hunter, the primary author of What's Wrong With Still Waiting for Greenhouse.

John Daly and the Straw Man Argument

Ken Miles, 18 August 2003

A straw man is a type of logical error where one misrepresents and distorts an opponents argument, and then proceeds to attack this false argument (the `straw man'). It’s also a tactic which is commonly used by Australian pseudo-scientist John Daly in his efforts to discredit global warming.

In an attempt to debunk a paleoclimate reconstruction by Michael Mann, Raymond Bradley, and Malcolm Hughes (Mann et al., 1999); John Daly misrepresents their argument three separate times, and then proceeds to refute the straw man which he has created. Daly’s article is titled The ‘Hockey Stick’: A New Low in Climate Science, which is ironic given that Daly distorts the paper so much that it is essentially unrecognisable.

His first misrepresentation starts when Daly writes `Using tree rings as a basis for assessing past temperature changes back to the year 1,000 AD, supplemented by other proxies from more recent centuries .....'. This statement is incorrect. The other proxies which Daly refers to, are not from more recent centuries, but rather, go back further in time than the tree rings. Daly then bases his entire attack on the accuracy of the technique solely on tree rings. The other proxies are simply ignored. While this error could have been simply a result of Daly misinterpreting the paper, I alerted him to this error in March 2003. It still hasn’t been corrected.

His second misrepresentation is more serious. He states `Mann completely redrew the history, turning the Medieval Warm Period and Little Ice Age into non-events, consigned to a kind of Orwellian "memory hole"'. This statement is completely wrong. Mann makes this statement in his paper `our reconstruction thus supports the notion of relatively warm hemispheric conditions earlier in the millennium, while cooling following the 14th century could be viewed as the initial onset of the Little Ice Age sensu lato'. Orwell would be turning in his grave (or perhaps laughing at the irony) if he knew that Daly was using his name, while making statements that are exactly 180 degrees to reality.

Daly’s third misrepresentation involves how Mann and co-workers made up their reconstruction. Daly states `At that point, Mann completed the coup and crudely grafted the surface temperature record of the 20th century ..... onto the pre-1900 tree ring record. The effect was visually dramatic as the 20th century was portrayed as a climate rocketing out of control'. Once again, this is incorrect. Interestingly, Daly reproduces (and colours in) a graphic from Mann (1999), but neglects to include the second part of the graph from the paper. Had he done so, it would be clear that the reconstruction (which goes to 1980, not 1900 as asserted by Daly) is placed next to the instrumental record, rather than the crude grafting as he asserts. The reconstruction complements the instrumental record.

So, how do these misrepresentations help Daly? The first, allows him to concentrate on attacking the dendrochronology data. By consigning the ice core data to a kind of Orwellian `memory hole', Daly can ignore it, and focus his attack on the tree rings.

The third misrepresentation allows Daly to cast further doubt on the quality of the work. He attacks the authors for grafting two different records onto each other. This attack would be impossible to make had he honestly described their work.

However, it’s the second misrepresentation which is the best example of a straw man argument. Having falsely claimed that the paper doesn’t show a medieval warm period, nor a little ice age, Daly makes the following statement `to disprove the "Hockey Stick", it is sufficient to merely demonstrate conclusively the existence of the Medieval Warm Period and/or the Little Ice Age in proxy and/or historical evidence from around the world. According to the "falsifiability" principle of science, substantial physical evidence that contradicts a theory is sufficient to "falsify" that theory. To that end, "exhibits" of physical evidence are presented below to prove that not only is the "Hockey Stick" false, but that the Medieval Warm Period and Little Ice Age were not only very real - but also global in extent'.

In conclusion, only by dishonesty misrepresenting the contents of the paper, can Daly effectively attack it.


Daly, J.L.. The `Hockey Stick': A New Low in Climate Science,

M. Mann, R. Bradley and M. Hughes, 1999. Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, Geophysical Research Letters, Vol. 26, 759-762.

18 August 2003