Not me you silly – that’s a quote from WUWT. And as if in answer to his desperation, along comes The effectiveness of CO2 as a greenhouse gas becomes ever more marginal with greater concentration, a deeply stupid post.
It starts with a nod towards pretending to have a clue:
According to well understood physical parameters, the effectiveness of CO2 as a greenhouse gas diminishes logarithmically with increasing concentration… This inconvenient [sic] fact is well understood in the climate science community…
…because not even WUWT readers are going to fall for the idea that it’s a surprise that CO2-effectiveness-is-log. He does feel obliged to pretend IPCC has “hidden” the obvious, although I’m not sure why – a token gesture to stir up the unwashed masses, or a feeling that since its a post at WUWT it really needs to have some obvious lies in it? But its unconvincing, as a commentator writes:
The sentence in chapter 2 AR4 “Note that for CO2, RF [radiative forcing] increases logarithmically with mixing ratio” is so very well hidden. You would never know it was there if you didn’t read it.
But, that’s not the main reason I want to take the piss out of this particular article. That is reserved for:
From the present concentration of atmospheric CO2 at approaching 400 ppmv, only ~5% of the effectiveness of CO2 as a Greenhouse Gas remains. This can only give rise to a maximum of a further of ~+0.21°C. Thereafter beyond 1000+ ppmv the effect of increasing levels of CO2 can only ever be absolutely minimal even if CO2 concentrations were to increase indefinitely.
Yes, really. He thinks the log function is bounded above. Truely this is the level of sophistication expected at WUWT. I can only echo commentator “Janice Moore” who enthuses:
WAY TO GO, WUWT SCHOLARS!!! YOU ARE THE BEST.
However, this stuff is so obviously drivel that not even all the WUWT readers fall for it. The fourth comment points out its all wrong. A little lower down, “Phil.” tries to rescue WUWT commentators well deserved reputation for stupidity with a high-scoring “But at higher concentrations it will transition to a square root dependence which will give a higher sensitivity” (its the other way round: CO2 goes linear – squareroot – log, though I forget at what levels [Update: my commenters seem to be telling me I'm wrong about that. Ah well. I don't believe it leads to higher sens, though]).
* CO2 – An Insignificant Trace Gas? Part Seven – The Boring Numbers – the best on-line ref for “its log” that I could find. Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Twelve – Curve of Growth looks to be good for linear (which is obvious) and square root (I didn’t trouble my pretty head with the details). Calling Eli…