2011-01-27 14:36:16Monckton Myth #10 - help on an IPCC reference
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

 I'm working on Monckton Myth #10, and he made the following statement in his point #23:

"The IPCC itself only expects about 57% of equilibrium warming to occur by 2100"

Anybody know where he gets this 57% figure?  It seems to me like the fraction of warming by 2100 should depend on how our emissions change by 2100.

2011-01-27 14:47:45
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Dana,

I'll have a look-- but it could be like trying to find a needle in a haystack.  Google offered nothing.  It is very annoying when the deniers do this sort of thing.

Shouldn't you be taking it easy after fighting off the invective and vitriol at the Guardian? 

2011-01-27 15:19:54taking it easy?
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

What's that saying?  I'll get plenty of sleep when I'm dead?  Anyway, I'm trying to get this one out of the way so I can work on skewering Lindzen in more detail (actually looking at the numbers quantitatively).  Besides, I was going to watch 'Top Chef' tonight, but the bastards ran last week's episode.

I ran the numbers and they seem a bit strange.  For example, Scenario A2 puts the warming between 2000 and 2100 at 3.4°C, and the atmospheric CO2 in 2100 at about 850 ppm.  So the equilibrium warming from pre-industrial is:

dT = 0.8*5.35*ln(850/280) = 4.75°C.  Or about 4°C above 2000 temps.  Yet the warming by 2100 is 3.4°C above 2000 temps:

So we see 85% of the equlibrium warming by 2100?  Based on the trajectory of the graph, it's a little hard to believe that the red line could plateau at 4.0°C.  But maybe that's because CO2 concentrations are accelerating so rapidly that cutting the increase down to zero would be a radical change.  Am I missing anything?

2011-01-27 15:46:43Some ideas
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Dana,

I have had a quick look at AR4.  As you know, the IPCC states that the most likely value for EQS is for doubling CO2 equivalent is +3 K.  Now 57% of that is about 1.7 K.  Only one emissions scenario results in a global SAT anomaly near that value, and that is B1 which is projected to lead to a warming of +1.8 K (from Figure 3.2 in Synthesis report) by 2100. SRES B1 results in a CO2 concentration of 550 ppm, or 590 ppm CO2 equivalent.

This book by Solomon may be helpful-- see page 827.  The examples she gives (from TAR)call for 70% of warming by 2100 for SRES B1 (+2.3 K at 2100 [for Co2e of 590 ppm) versus +3.3 K for equilibrium warming]. Maybe email her...seriously, get the information from the top dogs. The scientists at RC will have some insights or thoughts on this.  I have emailed Gavin before and he has always responded. Maybe also give him a shout.  Anyways, 57% sounds way too low.

It might be impossible to nail Monckton down on this because he does not state which SRES scenario he is referring to, or which IPCC report, and he does not explicitly state what he understands the EQS to be for doubling CO2 equivalent.  Earlier in his piece he is chunnering on about freezing emissions....But maybe noting these various failings is enough to debunk him.  

Maybe one could provide an example of your own. Assuming a relatively optimistic scenario (A1B-- peak in CO2 emissions near 2050, with a slow decline thereafter),  projections call for a warming of about +2.8 K in 2003, and +3.6 K by 2300 (so almost 80% of warming by 2100).  Even for the aggressive B1 scenario, the warming by 2100 is +1.8 K, and +2.2 K by 2300 (again, about 80%).

 

 

Actually, upon reading his diatribe at WUWT, I do not know WTF he is trying to say. I think it safe to say that some pretty creative maths (sorry trickery) went into his calculation.

 


 

2011-01-27 15:53:06
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Hi Dana,

We cross posted-- looks like we are on the same wavelength. Oh crap, I am tired and read the anomalies wrong.  Ignore this (need to add about +0.8 K to the numbers, the fraction of warming should remain the same though):

"Maybe one could provide an example of your own. Assuming a relatively optimistic scenario (A1B-- peak in CO2 emissions near 2050, with a slow decline thereafter),  projections call for a warming of about +2.8 K in 2003, and +3.6 K by 2300 (so almost 80% of warming by 2100).  Even for the aggressive B1 scenario, the warming by 2100 is +1.8 K, and +2.2 K by 2300 (again, about 80%)."

 

 

 

2011-01-27 15:58:09sounds right
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

Thanks Albatross.  Solomon's numbers are pretty close to mine - a few tenths difference, but I'm kind of eyeballing it:

 

That makes me feel a bit better, that I'm not missing something.  No idea where Monckton got that 57% figure though.

2011-01-27 16:44:35
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

No worries, any time.  Just a note of caution, I think those numbers that Solomon cited are form TAR not AR4.

Is that Table yours, or from Solomon's book?  Regardless, maybe a similar Table could be included in your post.  What worries me about all this is that some claim +2 K warming is considered to be "safe", yet even scenario B1 (with aggressive emission cuts), may lead to an additional +2.5 K warming above 2000 temps. by 2100.  So much for Monckton saying that there is nothing for future generations to worry about....

Are the D-K and trolls still at it on the Guardian forum?  "Whack a troll"-- I like it ;)

Had to use "Albatross2", b/c someone had already taken "Albatross".

 

2011-01-28 02:56:52
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

It's my table, and I put it in the post.  Maybe the TAR vs. AR4 accounts for those few tenths of a degree difference.  Or maybe it's my eyeballing.

Seems like the trolls have slowed down a lot on the Guardian.  I haven't checked it since last night, but there weren't a lot of new comments yesterday.  I think it's pretty well saturated - the deniers have made their point defending Lindzen and attacking the IPCC with stupid arguments, and in the process, have made my point that they're not actual skeptics.

2011-01-28 03:23:28
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206
Good work Dana.....look forward to seeing the post.
2011-01-28 03:49:34thanks
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

Thanks, I've got all the info in there now, it just needs some polishing.

Coincidentally, I was wrong about the Guardian.  At least one new denier "tomtom" has cropped up overnight.

2011-01-28 08:16:50SPPI
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Dana,

Ignore the trolls ;)   They are propbably trying to bait you into saying something silly and then will then use it to discredit you elsewhere.

Just read this at SPPI....might give some insight into Monckton's 57%-- just skimmed it though!

 

 

2011-01-28 08:20:01
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206
Munchkin mentions 57% here.
2011-01-28 08:28:31thanks
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252
Thanks Albatross. Although he says the same thing in both documents (57% and 'a little more than half'), he never actually says where it comes from, except to claim that's what the IPCC has said.  He probably just misunderstood something in the report.
2011-01-28 10:48:50
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

"He probably just misunderstood something in the report."

 

You are too generous Dana...he knows damned well what he is doing...at least when it comes to fiddling numbers.

2011-01-28 23:19:00Slow feedbacks
James Wight

jameswight@southernphone.com...
112.213.158.135

As far as I’m aware the IPCC projections only take into account fast feedbacks; ie. a climate sensitivity of 3°C. Hansen has argued that slow feedback sensitivity is as high as 6°C when there are ice sheets on the planet, as there are today. That would leave a lot of warming to come after 2100 - though obviously it can’t be what Monckton is referring to because he believes in a low climate sensitivity anyway.

2011-01-29 08:06:13
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252
Yes I included a brief discussion of the long-term sensitivity in MM #10.
2011-01-29 21:26:57
MarkR
Mark Richardson
m.t.richardson2@gmail...
134.225.187.80

Also, you're only looking at CO2.

 

Have you checked the CO2-eq figures by then or net radiative forcing? 

Until now everything except CO2 has roughly cancelled out. But if the SRES expect a decline in aerosols/land use albedo relative to other greenhouse gases then that could significantly boost the estimate.

 

 

 

Of course, it's possible that Monckton used the 4.5 K sensitivity. You got 86% for A2, if you divide that by the 1.5 you get from the sensitivity difference you get 57%?

Monckton has a tendency to make up IPCC projections and then lie about them, we already knew that.

2011-01-30 04:14:58net forcing
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210

That's a good point Mark, I don't know how the IPCC scenarios project other forcings (particularly aerosols and other GHGs) to change by 2100.  The only problem with the IPCC report is that it's so large, it can be hard finding a specific piece of information like that.  I'll have to look around.

If Monckton used a 4.5°C sensitivity, he should have specified that, since it's on the high end.  But I'll clarify that my figures are using the most likely value of 3°C.