2011-05-18 01:44:36Humlum is at it again
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Julien wrote a post in response to an Ole Humlum denialist article in a Norwegian newspaper.  See here:

Humlum is at it again

2011-05-18 05:24:54
julienx2k2

julienx2k2@gmail...
188.113.75.196

I have updated the translation - and have added the their first letter.

I am realizing there are several additional points we haven't answered to:

-cloud cover

-the reasons for temperature changes during the present interglacial, that would explain their assertion that the mean temp has dropped by 0.8 deg instead of increasing by 0.3 as the "CO2 hypothesis" says.

If anybody has ideas how to insert answers to that it'd be perfect!

2011-05-18 05:40:32
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

They're right that models have a hard time predicting cloud cover changes.  I don't think that point requires a response, because so what?  Models aren't perfect.  That's not a newsflash.

The pre-industrial temperature drop is a consequence of the Milankovitch orbital forcing.  The short answer is that the AGW theory doesn't say that natural factors can't impact global temperatures too.

2011-05-18 06:23:27
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.113.158

Humlum humbug?

2011-05-18 06:25:20
julienx2k2

julienx2k2@gmail...
188.113.75.196

updated the post :)

2011-05-18 14:59:04
Agnostic

mikepope_9@hotmail...
118.208.166.133

Dana

"The pre-industrial temperature drop is a consequence of the Milankovitch orbital forcing"

Are you sure? 

I thought present eccentricity is such that the earth is following an almost circular orbit around the sun and would not have deviated significantly from that in the past 200 years, indicating temperature stability.

The earths axial tilt (23.45°) has been falling from its maximum and since the obliquity of the ecliptic changes very slowly (41k years), polar regions should be receiving minutely less exposure to solar radiation.   True this suggests very slight cooling but surely so little as to be negligible ?

Humlum may have more knowledge in this area than I do - which admittedly is small.

2011-05-18 15:50:07
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.113.205

Agnostic, perhaps Dana is referring to the cooling from the Holocene Climatic Optimum? That would be my guess. 

2011-05-19 00:13:22
Tom Curtis

t.r.curtis@gmail...
112.213.134.51

 "Worse than that, comparing the simultaneous temperature and CO2 concentration is extremely misleading, as every concerned person knows that the climatic system has a large inertia.  This means that the full effects of the explosion of the CO2 atmospheric content we are causing will be seen in several decades only – but then again the GISP2 data won’t be representative of the global situation."

 

I don't think this is relevant.  It is very relevant at century timescales up to a century, but in the millenial timescales shown by the GISP2 record, thermal inertia would not significantly distort the graph.

 

On the other hand, specific mention of the increased albedo of the Earth resulting from more extensive snow and ice from the Holocene Climactic Optimum to the present as a significant cooling factor is probably worth mentioning. 

 

Other than that, I liked it.

2011-05-19 01:15:24
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

Agnostic - like Rob said, I'm referring to the orbital forcing over the past 6,000 years, which is the period Humlum referenced.  I don't know how large the orbital forcing has been over that period, but it's been negative.

2011-05-19 01:33:16
julienx2k2

julienx2k2@gmail...
129.241.89.163

Ok Tom, thanks for the comment. I am mentioning the simultaneous stuff because BHS imply in their letters that the current laarge CO2 increase hasn't led to a large temperature increase. They constantly imply in their arguments that T follows immediately [CO2]; and since their red dotted line doesn't point towards a large T increase in spite of exploding [CO2] they conclude that natural factors steer the climate.

This is why I felt I had to precise the inertia stuff.

If you have a reference for the albedo change I'll put it in the post!

Thx again

I'll have a look at the IPCC WG1 tonight to see what they say about the HCO, but I don't feel we need to go deep in the details that explain the slight cooling since then - pointing to references and mentioning it has "well known natural factors" is good enough I find.

2011-05-19 14:26:29
Tom Curtis

t.r.curtis@gmail...
112.213.134.51

Sorry julien, I can't help you with actual figures.  Based on Flanner, the effect should be about as strong as the positive forcing from CO2 over the same period, or stronger if (as is sometimes claimed) the HCO was 2 degrees warmer than the preindustrial average.

2011-05-20 19:31:22
julienx2k2

julienx2k2@gmail...
129.241.89.163

ok, i guess I'm satisfied with the post now. Concerning the reasons for the cooling during the late part of the Holocene I suggest that we deal with that in another post, dedicated e.g. to "how natural factors have steered the climate in the Holocene" or alike.

J

2011-05-21 01:56:53
dana1981
Dana Nuccitelli
dana1981@yahoo...
64.129.227.4

I think it looks good, julien.  I've got it on the schedule to be published in the next day or two, if that's okay with you.  Do you want to keep the title as is, or change to "Humlum Humbug" as Rob P suggested?

2011-05-21 21:03:09
julienx2k2

julienx2k2@gmail...
188.113.75.196

ok for me any time :) Dunno for the title. Let's keep "at it again" for  this time, and keep humbug for the next ;)

2011-05-23 08:04:46
oslo

borchinfolab@gmail...
90.149.33.182

Great article Julien.

The english translation of BHS is not available to the public - could someone fix this?

2011-05-23 08:25:25
dana1981
Dana Nuccitelli
dana1981@yahoo...
69.230.97.203

Whoops.  I changed it to Embargoed.  I think that should do the trick.

2011-05-23 08:50:50
oslo

borchinfolab@gmail...
90.149.33.182

Thanks dana - there is an embargo message at the top which is a bit confusing.

2011-05-24 21:35:29
julienx2k2

julienx2k2@gmail...
129.241.89.163