Seriously - how is the causality established, as distict from co-occurence, regarding any warming (cyclical) and CO2 amounts (also cyclical even if now obviously greater than at the last few peaks)?
I mean what would you accept as proof of co-occurence or coincidence and therefore a logical proof of no causal relationship?

freediver wrote on Oct 17^th, 2008 at 11:23am:


Dogshit is a much less complex phenomenon than the weather. You must not let an analogy run away with you.

Soren wrote on Oct 17^th, 2008 at 11:22am:


You're talking about proofs again. Proofs occur quite often in mathematics, but very rarely in natural systems. We need to get back to the basics. Carbon Dioxide is a greenhouse gas. The dominant greenhouse gases (that absorb infrared radiation) are water vapour, carbon dioxide, ozone, methane and nitrous oxide.

Basically, what greenhouse gases do is to trap heat within the troposphere. This is basic physics. If you want to read up more on the Greenhouse effect, I can provide a reference.

Carbon dioxide occounts for about 1/4 of the Greenhouse Effect caused by water vapour, however if you reduce atmospheric temperature, water vapour drops out as rain whereas carbon dioxide does not. The water vapour concentration in the atmosphere is driven by temperature. It's termed a feedback, whereas Carbon dioxide is a forcing. The temperature change due to CO2 is given by the forcing equation:

dT=[alpha]ln([CO2]/[CO2}orig)/(4[sigma] T^3, which we obtain from the derivative of the Stefan Boltzmann equation.

The actual CO2 contribution is relatively low, however the resulting water vapour feedback is what predominantly causes the warming effect. As I said previously, you're talking about a ratio of about 4:1 depending on the relative humidity.

We're jumping ahead of the explanation I was giving, but I'll come back to carbon balance, probably next week.

The next part of the puzzle is to look at general circulation models.  

I should ask you the same question as Grendel - In the Mauna Loa atmospheric CO2 Graph for the last 40-50 years, why do you think there are seasonal variations in CO2 concentration, and what is the period of those variations?

I'll also ask any of the deniers to tell me the significance of the ln (the natural log) in the forcing equation above. You can ask your pseudo experts in the denialist forums and blogs. They probably won't know either, although it's one of the half truths they spout in parrot fashion, not understanding a word they say.

Odd that a scientist would go to a newspaper for answers rather than his colleagues. Odd that he would provide a question rather than an answer. Scientists normally consider it their duty to inform the public, not confuse them.

What do you expect from the deniers Soren...  it's always shoot the messenger.

Soren wrote on Oct 22^nd, 2008 at 10:28am:


Yes, I am insinuating that it is odd that he posed the question, but did not give the answer. Scientists are usually keen to inform the public.