Comments 1 to 10:

1. YubeDude at 11:25 AM on 1 October, 2012
   I would like to see two distinct threads. One on the science exclusively and the other on policy and amelioration. When the later starts to challenge the former we lose objectivity when assessing the science.
   No doctor would make a diagnosis based on treatment protocols or cost; the diagnosis is based completely on the metrics at hand.
   Along those line I would like to see more articles that address the sophistry of skepticism which is dependent on conflating objective data streams with subjective policy.
   
   On the pure scientific front, I would like to hear from an atmospheric chemist on whether CO2 that carries the combined 18-O (combustion) and 12-C (old carbon) signatures are regarded as the Anthro-CO2 smoking gun. What papers I have found and read suggest but still leave vast wiggle room. In particular I have not found any research that looks directly at the combined signatures in CO2.
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2. TomPainInTheAsk at 12:07 PM on 1 October, 2012
   I second YubeDude's request! Issues concerning policy and amelioration become political very quickly. Perhaps that is inevitable; financial resources are involved.
   
   IPCC Work Groups provide a separation of the science from more political aspects. It's a good idea.
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3. TomPainInTheAsk at 12:11 PM on 1 October, 2012
   I also agree with YubeDude's second request: Please, more articles that examine the techniquest behind the skepticism (& denialism) arguments manufactured by people who are real pros at it.
   
   (-snip-). The new Spin Doctors are light-years beyond that now.
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   Moderator Response: [DB] Inflammatory snipped.
4. Estiben at 12:35 PM on 1 October, 2012
   Could you post more replies to the "it's too hard/too expensive" lines? I keep getting hit with comments about windfarms chopping up birds, or that solar can never supply all our energy needs, or that going off coal will wreck the economy. But don't stop what you've been doing, you're the best in the business.
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5. actually thoughtful at 13:01 PM on 1 October, 2012
   Solutions.
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6. heijdensejan at 04:25 AM on 2 October, 2012
   What I would like to see explained is the following (or a link to a good blog post) How did anybody calculate that a doubling of CO2 results in a forcing of 3.7 W/m2 and a 1.1C temperature increase without any feedbacks.
   
   Maybe there is a SkS post somewhere but somehow I have never found it....
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7. KR at 05:03 AM on 2 October, 2012
   heijdensejan - I would suggest looking at the How do we know more CO2 is causing warming thread for a discussion on this.
   
   The best reference I could give you would be to Myhre 1998: he ran the radiative code for air columns at several different locations (Northern Hemisphere, Southern Hemisphere, tropical), based on the HITRAN spectral data, and came up with:
   
   dF = 5.35 ln(C/Co) W/m^2
   
   as the fit to the relationship between CO2 increase and forcings. That kind of radiative estimation is essentially a numeric integration of the spectral response from surface to space of the specified atmosphere - lots of number crunching, but fairly straightforward if you have good spectra.
   
   From the 3.7 W/m^2 that produces for a doubling of CO2, and the Stefan-Boltzmann relationship, given an observed Earth emissivity to space of 0.612 in the infrared (which matches current temperatures and incoming energy), the surface of the Earth must warm by 1.1°C to radiate an extra 3.7 W/m^2 in balance.
   
   The actual effect is that the IR emissivity to space decreases, rather than input energy increasing, but for a first-pass estimate there's no significant difference in the numbers.
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8. Bob Loblaw at 09:01 AM on 2 October, 2012
   If you want to actually run a one-dimensional (vertical) radiative transfer model to see how it behaves, MODTRAN is available on-line.
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9. JoeT at 06:32 AM on 3 October, 2012
   I would like to see more in depth discussion of how climate change affects drought and food production .. that is, more than "the wet gets wetter and the dry dryer". I'm still having a hard time understanding what the basic physics is and what assumptions different models make.
   
   I'll give an example: If you look at the August, 2012 paper published by Dai you can see in Figure 2, his prediction that the Sahel region in Africa will have more rainfall. But he writes:
   
   "Most CMIP3 models produce ... increasing precipitation over the Sahel in the twenty-first century1, although a few models do produce some drying over the Sahel under a uniform ocean warming."
   
   The model that Dai refers to that predicts increasing drying in the Sahel is by Isaac Held and co-workers at the Princeton GFDL. At the GFDL website, Held has a nice write-up about drought in the Sahel. In particular it is fascinating to see his graph showing that when the SST in the Southern Atlantic is greater than in the North, drought occurs. The question is, what happens when the ocean temperature world-wide increases? Will there be drought in the Sahel or not? Dai and Held seem to have different answers. That's not a problem. What I'd like to know is why do they have different answers?
   
   As part of this it would be nice to know what influence the movement of the ITCZ has on drought as in this fascinating article in Scientific American
   . What happens to the size of the Hadley cells? -- do they get bigger, smaller? Do they translate north and south with the ITCZ?
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10. doug_bostrom at 02:44 AM on 21 October, 2012
    Test.
    
    Edit test.
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    Moderator Response: Test.

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