On Tuesday I attended a Skeptics in the Pub evening, at which a talk was given by atmospheric physicist Professor Fred Singer.
His talk focused on why the data in the IPCC reports does not match up with its conclusions in the summary for policy makers. It was all fairly un-contentious stuff, problems that all but the most ardent global warmer will admit exist: the models have not been validated, predict troposhperic warming we don’t see in the observations and are uncertain about clouds; carbon dioxide levels don’t correlate with recent temperatures because CO2 has been going up and up while temperature of late has remained largely flat. These are arguments I am familiar with from following the work of people like Steve McIntyre and Anthony Watts. Singer invoked Popper, pointing out that concensus means little when one piece of evidence can refute a hypothesis. Surely he would be popular with skeptics used to having to explain the scientific method to creationists!
But it was not that simple. People I assumed would be a natural audience for Singer were in fact highly skeptical of him. I heard mutterings from many in the audience along the lines of, “I know when I’m being fed bullshit, and this is bullshit.” But skepticism is not about having a “bullshit detector”. It’s about critical thinking and considering the evidence. A maxim oft quoted by skeptics is that extraordinary claims require extraordinary evidence. It seems clear to me that the IPCC is the one making the extraordinary claim, that they are 90% certain that climate change is anthropogenic. How can they be so certain when there is only one Earth’s atmosphere to measure so we can’t simply remove the effects of man and see what happens? And here is Professor Singer explaining why the IPCC’s evidence is not so extraordinary.
One questioner seemed to equate Singer with conspiracy theorists. How can 2,500 scientists be either wrong or lying? Singer tried to explain how the IPCC works: that it is not made up entirely of scientists, that even those who disagree are counted among the 2,500, and that the summary is written separately from the report, by political delegates. It does not take a conspiracy to explain the discrepancies. The problems Singer presented are indeed debated heartily in the scientific community, but because they are complicated they are glossed over by the mainstream media. Politicians have their own reasons for not drawing attention to them.
I am skeptical of climate change alarmism for reasons I have stated before. The models don’t make accurate predictions and there are big problems with all the data sources except for the satellites, which are inconclusive. I was surprised that this was news to so many self-described skeptics.
Singer’s report is available online. It includes a graph (figure 3b on page 4) of paleo temperatures without using tree ring proxies. This graph makes the 20th century look unexceptional. McIntyre has been very skeptical of tree ring proxies. The latest is that leaves appear to remain at a constant temperature, casting more doubt over them.
It does help with skepticism if you have a bullshit detector, such as this one :
http://www.xenu.net/archive/baloney_detection.html
Of course, whether the detector should go off more when pointed at the IPCC, or when pointed at the NIPCC is the question.
Particular principles which might help the NIPCC’s (the “warming isn’t our fault”) pointo f view are :
1. Arguments from authority carry little weight
2. If there is a chain of argument every link in the chain must work.
3. Conduct control experiments (bit hard to do with the earth)
4. Argument from adverse consequences is no good
5. Post hoc, ergo propter hoc
Principles which might help the IPCC (the warmers):
1. Appeal to ignorance (absence of evidence is not evidence of absence).
2. Suppressed evidence or half-truths
Other principles which both sides should be aware of:
1. Observational selection
2. Post hoc, ergo propter hoc
3. Statistics of small numbers (such as drawing conclusions from inadequate sample sizes).
Thanks Gib, a nice summary there!
Two others seem pertinent to the debate about how to interpret the fact that in ice core data, CO2 increase happens after temperature increase.
1. Spin more than one hypothesis – don’t simply run with the first idea that caught your fancy.
2. “Occam’s razor” – if there are two hypothesis that explain the data equally well choose the simpler.
E.g., here is the argument from the warmers’ POV.
I was there too (I was the one who asked the question about validation of the models).