I found one of the comments to be a fine example of Alarmist dogma given that they are desperately looking for “Positive Feedbacks” to amplify the effect of CO2.
QUOTE:
CO2 is a greenhouse gas so it raises the earth’s average surface temperature. This increases the average water vapor level which also tends to warm things up.
UNQUOTE
http://www.realclimate.org/index.php/archives/2012/12/a-review-of-cosmic-rays-and-climate-a-cluttered-story-of-little-success/comment-page-1/#comment-312643

Nir Shaviv says that increased water vapor in the atmosphere increases the cloud cover which constitutes a net cooling (negative feedback). This makes sense to me except in the case of “Snowball Earth” where the planet’s albedo won’t be much affected by clouds.

Here is how I see it. On the one hand we have the Arrhenius theory that fails on all time scales except (maybe) 1850 to 1998.

On the other hand we have Nir Shaviv with a theory that fits observations on many timescales but does not look good over the last 60 years.

Clearly neither theory explains observations completely but you should admit that Shaviv makes more sense than Arrhenius:

George B’s suggestion that re-glaciation delivers positive feedback by rejecting incoming solar radiation makes perfect sense. Finally a “Tipping Point” that might have some basis in reality. What I would expect from my non-linear circuit theory experience is that the climate would then be permanently stuck at “COLD”. We know this is not the case, so what provides the kick to start the inter glacials?

With regard to David Appell, Verity was kind enough to grant me the power to “Zap” trolls here but I decided not to use it given that I have publicly criticized the IPCC, SkepticalScience etc, for censorship or lack of openess. He hurts his cause much more than ours.

I’m telling you, this could go viral in a heartbeat…

The galactic arm effect has to do with the oscillation between those times when Ice Age glacials can happen, and those times when they can not.

Withing this one ice age the cycle of glacials and interglacies is explained by the amount of sunshine more than 60 degrees north. We’re just a couple of Watts away from the “trigger” value. We have been getting longer N. Hemisphere summers for a few thousand years now, so could keep on melting the ice. There’s a fairly good time (about 2000 years) until we get back into the ‘short summer’ cycle again, and once again are at risk of “tipping” into a new glacial. See the chart here:
http://chiefio.wordpress.com/2013/02/11/interesting-change-of-season-length/

At that point, all it takes is a slow down of the Gulf Stream and we ought to “lock up” into cold. The Gulf Stream periodically slows, most likely driven by a 1400 to 1800 year lunar / tidal cycle.

http://chiefio.wordpress.com/2011/11/03/lunar-resonance-and-taurid-storms/
references:
http://www.pnas.org/content/97/8/3814.full

Where this graph: http://www.pnas.org/content/97/8/3814/F2.large.jpg

puts the next big cold spike at about 3107 A.D. to 3452 A.D. when we will have another Little Ice Age. However, the summers are most likely too long then, and will be until about 1000 years past that. Which strongly implies the next most likely “window” is about 3500 A.D. to 5200 A.D. when the summer N.H. length is lowering and we are in a cold peak for that 1500 to 1800 year cycle.

So mark your calendar, that’s the most likely start of the next no-recoverable Glacial. The orbital processes set the table, then the lunar tidal tries to trigger it about ever 1500 to 1800 years. Once we’re average about 420 to 416 W/m^2 N. 60 degrees, then the lunar tidal trigger just needs to roll around to set if off.

The good news is that when it happens, Florida and the Desert Southwest of the USA are nice and pleasant. The Gulf Stream back sup, and those places get nice warmth with rains.
http://chiefio.wordpress.com/2012/12/15/d-o-ride-my-see-saw-mr-bond/

Yes, the precision isn’t all that great, but I think we can say about when the next glacial is most likely to commence.

Per: David Appell:

I think I hear a small mutt yapping in the distance. Can someone turn on the hose and squirt it?… I’m not fond of dealing with soiled trolls or I’d do it myself… (In other words, David ought not be surprised nobody responds as such insults don’t warrant it…)

@George B:

Yes, the major continent positions have to be “right”, but that’s an even longer process for change than the galactic arm cycle, so determines when Ice Ages are possible… (then the galactic arm triggers them… then the interglacials happen when we go above about 420 W then…)

Personally, I find the point of the article rather interesting… a conflict between the two graphs. You can only attribute CO2 causality to ONE of them, or the inherent conflict between them causes an eruption of trouble. Interesting point and interesting problem to set before “the team”…

Sorry, missed out the link

http://wattsupwiththat.com/2013/05/08/the-curious-case-of-rising-co2-and-falling-temperatures/
Tonyb