Wednesday, 10 August 2011

Clutching at Straws, or "Scraping the Barrel"

I used to like the Hockey Schtick, often first with news of new scientific papers or articles on global warming, until the blog became a mouthpiece for the Dragon Slayers with their distortions and pseudo-science. A recent post there claims that a climate scientist  "inadvertently explains why greenhouse theory is wrong". The post links to a video of Professor David Archer of the University of Chicago giving a lecture to non-science majors on modelling the "greenhouse effect":
In lecture 5, The Greenhouse Effect, Archer uses the Stefan-Boltzmann equation to calculate the supposed temperatures of Venus, Earth, and Mars with and without a greenhouse effect. Archer's calculations show the greenhouse effect on Venus is wildly underestimated by 415C and wildly overestimated on both Earth (by 23C) and on Mars (by 19C) in comparison to actual observed temperatures. This is despite the fact that CO2 levels are very high and virtually the same on Venus and Mars (around 96%) and only trace (0.039%) on Earth. Archer says in the lecture that one would have to assume the Venus atmosphere behaves like multiple panes of glass in order to obtain an answer near the observed temperature, yet on both Earth and Mars one would have to assume the atmospheres behave like much less than one pane of glass. 
What is not said is that in the lecture, Archer develops a very simple atmospheric model, using a "pane of glass" to represent a totally absorbing atmosphere, and at the end shows that its results are wrong for all three planets. So this post is claiming that a very simple "one-layer" atmospheric model, which as Archer explains is being used as a step towards a more accurate "multi-layer" model, and which produces the wrong results somehow disproves the "greenhouse effect"! Give me a break! Incidentally, what's "much less than one pane of glass", which it's implied Archer has said (he does not)? The post continues:
H/T Professor Claes Johnson, who explains why Archer also uses the Stefan-Boltzmann equation incorrectly (and here)
The first link which purportedly "explains why Archer also uses the Stefan-Boltzmann equation incorrectly" doesn't mention Stefan-Boltzmann at all. Misrepresent what was being taught in the lecture, leave out relevant parts, come to an unsupported conclusion. and supply a link which doesn't address what you claim it does.The entire post is really scraping the barrel.

No comments:

Post a Comment