2011-04-10 05:35:14Solar Hockey Stick
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203

I put together a blog post on the preprint of Vieira et al. reconstructing TSI over the Holocene, Solar Hockey Stick.  Let me know if you have comments.

2011-04-10 12:17:26Are you sure about those calculations?
James Wight

jameswight@southernphone.com...
112.213.165.37

1 W/m2 is approximately the amount of anthropogenic forcing the climate has responded to. That’s caused a warming of ~0.7°C. If solar forcing has an efficacy of 0.6-1.0 times CO2, surely 1 W/m2 should have caused 0.4-0.7°C warming, not 0.14°C.

This may actually better match observations. The instrumental record shows 0.7°C warming since 1950. Ljungkvist shows the Little Ice Age as ~0.7°C cooler than 1950, at least in the Northern Hemisphere. Ljungkvist also has two distinct periods of early warming, circa 1700-1750 and 1900-1950 (the latter also seen in the instrumental record). Both occur at roughly the same time as upward spikes in the reconstructed TSI.

Correlation doesn’t equal causation, but it looks to me like most of the pre-1950 warming was natural.

2011-04-10 13:19:08Forcing
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203
The change in TSI is 1 W/m2, but the forcing is much smaller (almost six times smaller, in fact). Most of the pre-1940 was natural, but it wasn't mostly solar. Thanks for the reminder though, I totally forgot to examine the LIA. I'll do that tomorrow.
2011-04-10 14:24:42Oh
James Wight

jameswight@southernphone.com...
112.213.165.37

My mistake. That makes sense now. I guess the warming during 1700-1750 and 1900-1950 was a mixture of solar/volcanic/ocean cycles/anthropogenic?

2011-04-10 15:22:12
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203
Yep, no doubt a mixture of a number of factors.
2011-04-10 17:13:43
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

James and Dana,

Correct me if  am interpreting these data incorrectly, but according to NOAA, the radiative forcing of GHGs in 2009 was about 2.7 W m-2, with CO2 contributing about 1.7 W m/2 of that.  The forcing from CO2 exceeded 1 W m-2 after around 1980, with total GHG forcing at that time near 1.7 W m-2.  Anyhow, these data suggest to me that the anthro 'signal' should have only emerged after the mid 70s or thereabouts.  Yes, very quantitative I know ;)

"The change in TSI is 1 W/m2, but the forcing is much smaller (almost six times smaller, in fact)"

Dana can you please explain to this fool (moi) why that is?

2011-04-11 01:01:01Alby
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203
On the first point, see my recent post on pre-1940s warming causes. CO2 caused about 0.2C warming in the first half of the 20th century, though some was offset by aerosols. On the second point, I discussed it in the article. There's a factor of 4 for spherical geometry, and .7 for albedo. Overall close to 6.
2011-04-11 01:32:44
Alex C

coultera@umich...
67.149.101.148

Why are you using HadCRUT for comparison to land temperature data?  The CRU manages the land temperature data only, so I think it would make sense to compare to their data only.

2011-04-11 02:16:49
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Hi Dana,

Can you tell that it was really late when i typed that?  OK, i'll read the damn article, jeez.  I'm making fun of myself-- we had a teacher in high school whose answer to our questions was usually RDB (read the damn book), he was usually correct.... ;)

PS: We have to take care of some household stuff today and I have a conference call this pm-- but I will give y/our blog post a critical read at some point and provide some feedback, it may be late though!

2011-04-11 03:11:10
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203

Alex - I dunno, Robert Way made that plot for me back when I did a Ljungqvist rebuttal.

Alby - hehe no worries.  Whenever you have time for a review, it would be appreciated.

I just added a paragraph on the LIA.  Pretty much the same conclusion - TSI can account for about 10-20% of the temperature change.

2011-04-12 01:07:02
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Dana,

May not be relevant, but just in case, have you seen this? H/T to Arkadiusz.

2011-04-12 02:01:56no
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

No, and I can only read the abstract.  I have to say, I'm pretty skeptical of the claims therein.

2011-04-12 02:13:14
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Me too Dana, it is a pretty obscure journal.....but I thought I'd let you read it first and then decide.

2011-04-12 02:36:40
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

I'll tell you, those "skeptics" are really good at finding controversial findings in obscure journals! :-)

I really have a hard time buying it, because most of the TSI increase was in the late 19th and early 20th century.  Then there was a significant warming from 1910 to 1940.  Seems to me like there wasn't much delay there.  I don't think you can attribute both the early and late 20th century warming to solar effects.  It just seems unphysical to me.

2011-04-12 02:42:57For once I get to help the heavy lifters with their weights
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

ftp://rock.geosociety.org/pub/reposit/2010/2010107.pdf