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2011-04-19 15:31:42 | Lindzen Illusion #1: We Should Have Seen More Warming | |
dana1981 Dana Nuccitelli dana1981@yahoo... 69.230.97.203 |
I drafted up LI #1, which is mostly a re-post of the 'Case Study of a Climate Scientist Skeptic." Except in the calculation this time, instead of trying to estimate the heat going into the oceans, I just used transient climate sensitivity, which I think is a better approach. I'd also appreciate feedback on whether the tone of the intro is okay. | |
2011-04-19 16:27:54 | "lit a fire under the buns" | |
John Cook john@skepticalscience... 60.231.60.165 |
Is that an expression? Very vivid imagery. But lest everyone be thinking about Jo Nova's buns, maybe you should just go with "lit a fire under the purportedly non-political global warming "skeptic" movement :-) | |
2011-04-19 18:16:06 | ||
nealjking nealjking@gmail... 84.151.40.157 |
Well, they'll have to think about CM's buns as well - that should put them right off! | |
2011-04-20 01:24:56 | hah | |
dana1981 Dana Nuccitelli dana1981@yahoo... 64.129.227.4 |
Well the expression is "lit a fire under his ass", but I didn't want to use that language :-) But I can certainly take the buns out too. | |
2011-04-20 08:26:20 | ||
Albatross Julian Brimelow stomatalaperture@gmail... 199.126.232.206 |
Dana, Not sure if you know, but Hansen has a new paper in the works in which he claims that the negative forcing from aerosols is -1.6 W m-2 +/- 0.3. Not sure whether or not this is helpful. That sounds like a really high value to me, on par with CO2 forcing alone no? I am a great lover of buns, but best to leave it out ;) Not sure about making reference to 'doped up', maybe something more sophisticated is in order. | |
2011-04-20 09:24:15 | Hansen | |
dana1981 Dana Nuccitelli dana1981@yahoo... 64.129.227.4 |
Thanks Alby. I saw that paper but didn't get a chance to read it. -1.6 W/m2 is definitely on the high side (about 0.4 W/m2 larger than the IPCC most likely value and almost as large as CO2, though that's now nearly 1.8 W/m2). Certainly plausible though. Maybe I'll run the numbers for that forcing as an alternative possibility. Maybe use 1.8 W/m2 for CO2 and -1.6 W/m2 for aerosols. I'll modify the language you mention a bit too :-) | |
2011-04-20 13:35:36 | right on | |
dana1981 Dana Nuccitelli dana1981@yahoo... 69.230.97.203 |
Funny, using those values, the "expected" warming comes out to 0.8°C. Suck on that, Lindzen! | |
2011-04-21 16:33:46 | ||
Rob Painting Rob paintingskeri@vodafone.co... 118.92.111.75 |
Looks good to me. | |
2011-04-21 18:19:10 | I got a different value | |
James Wight jameswight@southernphone.com... 112.213.169.211 |
Dana, you might find a basic error in my calculations again!
Equilibrium temperature change ΔT = λ*ΔF λ = 0.8 K W-1 m2 ΔF = GHGs – aerosols = 2.7 – 1.6 = 1.1 W m-2 ΔT = 0.8*1.1 = 0.9 K
Transient temperature change ΔT = λ*ΔF λ = 0.8 K W-1 m2 ΔF = GHGs – aerosols – energy imbalance = 2.7 – 1.6 – 0.6 = 0.5 W m-2 ΔT = 0.8*0.5 = 0.4 K
Turning the equation around to derive climate sensitivity: λ = ΔT/ΔF ΔT = 0.7 K ΔF = 0.5 W m-2 λ = 0.7/0.5 = 1.4 K W-1 m2 = 5.1 K per doubling of CO2 | |
2011-04-22 01:19:10 | ||
dana1981 Dana Nuccitelli dana1981@yahoo... 64.129.227.4 |
A couple things James. In the first set of calculations, I'd suggest using more up-to-date GHG forcings, which brings it up to about 2.8 W/m2 and the net to 1.2 W/m2. There's also the solar forcing if you want to be thorough, bringing it up above 1.3 W/m2, and ΔT to close to 1.1°C. In the second set again I'd up the ΔF by about 0.2 to 0.25, so the ΔT becomes about 0.6 K. That's a bit low, so it would suggest either the aerosol forcing or energy imbalance (or both) are slightly high. In the third set ΔT = 0.8 K and ΔF = 0.73 W/m2, so λ = 1.1 = 4.1 K for 2xCO2. | |
2011-04-22 15:04:46 | ||
James Wight jameswight@southernphone.com... 112.213.135.49 |
You’re right, the GHG forcing should be 2.8 W m-2 – I mistakenly rounded down instead of up. If anything I would think the energy imbalance is slightly low, because it’s being measured in a solar minimum and we don’t have good measurements of the deep oceans. If I correct the GHG forcing and add in the solar forcing, I get 0.6°C. But I still don’t get the 0.8°C you use in your article. And a 4°C sensitivity seems like it’s worth mentioning. | |
2011-04-22 15:20:25 | ||
dana1981 Dana Nuccitelli dana1981@yahoo... 69.230.97.203 |
Well I had a slightly different approach, using transient sensitivity instead of the imbalance, which is hard to measure. | |
2011-04-22 15:42:06 | Forcing | |
James Wight jameswight@southernphone.com... 112.213.135.49 |
But you also used a forcing of 1.5 W m-2. Where did the extra 0.2 W m-2 come from? | |
2011-04-22 16:05:19 | ||
dana1981 Dana Nuccitelli dana1981@yahoo... 69.230.97.203 |
Increasing aerosols to -1.6 W/m2 decreased it by 0.4, and increasing CO2 to 1.8 W/m2 increased it by 0.15 (in comparison to the IPCC numbers). | |
2011-04-22 16:46:07 | ||
James Wight jameswight@southernphone.com... 112.213.135.49 |
That’s still only 1.35. These equations are fascinating; ±0.1 here and there and you get quite different results. Rearranging the equations to derive the energy imbalance… Energy imbalance = ΔFe – ΔFt = ΔTe/λe – ΔTt/λe = 1.0/0.8 – 0.8/0.8 = 0.25 W m-2 (sub e = equilibrium, sub t = transient) …I get only 0.25 W m-2, much smaller than observed. | |
2011-04-23 02:34:49 | forcing | |
dana1981 Dana Nuccitelli dana1981@yahoo... 64.129.227.4 |
Oh, I think the discrepancy is that I'm using the net IPCC forcing (1.6 W/m2 anthro plus 0.12 solar) whereas you're just using GHGs and aerosols, right? | |
2011-04-23 13:37:51 | Okay, it's making more sense now | |
James Wight jameswight@southernphone.com... 112.213.160.149 |
Equilibrium temperature change: ΔTe = λe*ΔFe λe = 0.8 K W-1 m2 ΔFe = 1.5 W m-2 ΔTe = 0.8*1.5 = 1.2 K
Transient temperature change using energy imbalance: ΔTt = λe*ΔFt λe = 0.8 K W-1 m2 ΔFt = 1.5 – 0.6 = 0.9 W m-2 ΔTt = 0.8*0.9 = 0.7 K
Transient temperature change using transient climate sensitivity: ΔTt = λt*ΔFe λt = 0.5 K W-1 m2 ΔFe = 1.5 W m-2 ΔTt = 0.5*1.3 = 0.7 K
Climate sensitivity using energy imbalance: λe = ΔTt/ΔFt ΔTt = 0.8 K ΔFt = 0.9 W m-2 λe = 0.8/0.9 = 0.9 K W-1 m2 = 3.3 K for 2xCO2
Climate sensitivity using temperature change: λe = 1.5λt = 1.5ΔTt/ΔFe ΔTt = 0.8 K ΔFe = 1.5 W m-2 λt = 0.8/1.5 = 0.5 K W-1 m2 = 2.0 K for 2xCO2 λe = 1.5λt = 3.0 K for 2xCO2 | |
2011-04-23 14:12:46 | yep | |
dana1981 Dana Nuccitelli dana1981@yahoo... 69.230.97.203 |
Yep, that looks about right. |