After a couple of months absence, I decided to take a look again at the pit of denialism and logical fallacies that is this thread on Joanne Nova’s “global warming isn’t caused by humans” blog. If you scroll down to comment #110 you’ll see I responded to someone who had asked, “Can you name a single piece of empirical evidence that man-made carbon raises temperatures?” Note, a “single piece of empirical evidence” – not numerous pieces, not proof, but just one thing. You’ll see that I replied with, “…the cooling of the upper stratosphere. And no, that’s not due to ozone.” Follow the link and you’ll see that cooling of the upper stratosphere is a prediction of global warming caused by increased carbon dioxide. If such a prediction were found to be true, then this would be one piece of evidence of anthropogenic global warming (AGW).
Now, Joanne Nova has a sleazy little habit, which is to wait several weeks after a comment is made, and then go in and edit in her replies/rebuttals to comments such as the one I made. I was following this discussion for at least three weeks after I made that comment, with no response from Nova. But if you look now, at some later point she edited in the following undated reply:
Yes Sceptico [sic], still waiting for you to cite any evidence that it's not due to ozone, and here's the real kicker - even if it isn't all due to ozone, that doesn't prove it's due to carbon. Argument from Ignorance rears it's head again. Just because you can rule out other things proves nothing about carbon. For someone who points out logical errors, you sure make a lot of them yourself.
I’ll come to the evidence it’s not ozone in a minute. First, though, Nova demonstrates again her total cluelessness regarding logical fallacies. My comment was not argument from ignorance because my claim included positive evidence that the stratospheric cooling was due to CO2. By rebutting Nova’s claim that this cooling is due to ozone, I am not saying just because it’s not ozone it must be CO2; I’m just saying it’s not ozone. I had already said that cooling of the upper stratosphere is a prediction of global warming due to increased CO2. A prediction that is confirmed cannot possibly be argument from ignorance.
So why did I say the cooling in the upper stratosphere is not due to ozone depletion? From the Stratospheric cooling page I linked before:
The impact of decreasing ozone concentrations is largest in the lower stratosphere, at an altitude of around 20 km, whereas increases in carbon dioxide lead to highest cooling at altitudes between 40 and 50 km (Figure 3). All these different effects mean that some parts of the stratosphere are cooling more than others.
And they produce these graphs of cooling rates from 1980 to 1994 at different altitudes:
4. Cooling trends at different altitudes in the stratosphere. source: Ramaswamy et al., Reviews of Geophysics, Feb. 2001.
You’ll note that actual cooling noted is confined to altitudes of 45 and 50 kilometers. I see no cooling trend on the 22 kilometer graph. This is exactly what is predicted by AGW caused by increased CO2, but not what would be predicted by warming due to ozone depletion. It’s not ozone. Nova still says it’s ozone.
This Is Funny
So that’s my response. I’m not going to respond on Nova’s blog – I’m simply not going to engage with someone who will edit in her replies to my comments weeks later to make it appear that my comment was refuted and I couldn’t respond. But here’s something funny. I had signed up at Nova’s blog to receive email notification of comments made, so I would know if I needed to reply to anyone. Somehow, that meant that (unbeknownst to her) I had gotten onto one of Nova’s email lists where she sends out desperate appeals for help from her friends when she’s out of her depth. I know this because I received (undoubtedly by accident) the following email that Nova sent to her group on March 3rd:
Help. Sceptico and Chris are taking over. I'm chopping. I've cut out half his post so far, because it's boring me rigid that I have to explain everything to him yet again.
This is the long long long stuff below.
I'm going away for a week - flying tomorrow night. I don't want to advertise that or chris and scepticet might think they have free run. But they will unless I ban them. They are scaring off other people.
Joanne Nova - Director
(“Chris” is commenter Chris Noble, who was also attempting to educate Nova’s followers.)
I called Nova on that email, and she presumably thought better of “chopping” my post or banning me, although it didn’t stop her editing in her “rebuttals” once she realized I wasn’t reading the thread any more. It did result in an uptick in the number of lame responses to my comments, including the one I replied to as detailed above.
I will have a response to Nova’s “hotspot not found” posts at some time in the future.