Yesterday on the Steve Vizard show, two scientists presented opposing views on the global warming debate, skeptic and geologist Ian Plimer and warmist/meteorologist David Karoly. It is good to see both sides of the argument presented to the public, however I would rather the two went head to head, an actual debate.
Plimer talked about his role as a geologist and how through temperature reconstructions, we would never suspect carbon dioxide as a major driver of climate. Further it is a trace gas, 0.04% of the atmosphere.
Karoly right away got to talking about attributing observed climate changes to human activity. This is after all his chapter in the IPCC reports. He talked about fingerprints which is an area of productivity in the debate. He later implies skeptics cherry-pick the results they want, but this is what he does with his talk of fingerprints. Warmer nights, warmer winters and atmospheric temperatures rising before ocean temperatures constitutes all the evidence needed for Karoly to convict carbon dioxide of the crime of climate change.
Are these exclusive to greenhouse warming however? Warmer nights are more likely to be caused by the urban heat island effect. Warmer winters could also have the same cause. What is plainly clear however, is that the profile of warming observed (by latitude and altitude/1979-1999) is not consistent with greenhouse warming. There is approximately equal rates of warming at the surface and upper troposphere which on its own rules out the enhanced greenhouse effect. The stratospheric cooling observed, while consistent with greenhouse gases, is more likely the cause of ozone depletion which stopped after the implementation of the Montreal Protocol.
Karoly gives an insight into how the IPCC arrives at “consensus” (which as Plimer points out is not scientific). He claims they look at a “body of evidence” which is fair enough. However, this should not mean, as Karoly implies, that you disregard inconvenient papers as erroneous. It seems to me that the IPCC has just counted papers and assumed those that don’t fall into the “consensus” are irrelevant. Were it the case they do consider natural factors, they would at least mention Svensmark’s cosmic ray theory.
Then we hear a meaningless argument by authority, that all major scientific organisations agree, “even” geological societies.
Vizard poses a question that skeptics, in my opinion, put too much stock in. How can man’s 3% contribution play a significant part? I accept that nature’s sinks have been unable to cope with the extra input and like most skeptics, accept that man is causing most of the increase in carbon dioxide concentration. Though I am concerned the carbon dioxide record may not be accurate (see the part on Ernst-Georg Beck).
Vizard then asks Andrew Bolt’s favourite question, how much will this tax decrease the temperature by? Karoly, after first discussing how the tax will act as a “waste disposal”, admits it is small, but we will be doing our part. Interestingly, he claims our inaction will encourage other nations to “pollute”.
While it is refreshing to hear the science, I think it would be a lot more productive to allow two scientists from opposite sides to talk directly to each other in a public forum. Only then can we get a true debate. You would have to allocate more time for this, but with this tax bearing on us fast, with Tim Blair counting the days, it is in the public interest.