2011-03-19 11:38:47A post on solar evolution?
Chris Colose


In some of the more recent comments on my post about the CO2-free atmosphere, there has been a little discussion developing concerning how well we know that the sun has been brightening over geologic time, as is so commonly talked about in relation to the faint young sun paradox and so forth.  I thought it might be a useful primer to put something on the internet concerning the underlying physics of why our sun evolves that way, and perhaps tie it into some broader issues in planetary climate.  There's not too much on this in actual climate related internet venues.  I probably couldn't relate this to any skeptical claims, but I'm wondering if it would be a good idea to put up something on this for reference? I could talk about this subject fairly confidently. 

2011-03-19 12:39:59
Daniel Bailey
Daniel Bailey

The faint young sun is a major stumbling block for denialists to understand.  Your posts are always informative & accessible, yet in-depth enough for all but the sharpest (of which I am not one).

I would welcome this.

2011-03-19 15:31:41sure
Dana Nuccitelli

Sure, it could be interesting blog post.

2011-03-19 18:15:05Would be a welcome reference
John Cook

Occasionally when skeptics say "CO2 was higher in the past", and it's explained that the sun was cooler in the past, the skeptic responds "sez who?!" Such is the anti-science attitude, any inconvenient science is denied. Having a post on this would be very welcome. It could be linked to from the "CO2 was higher in the past" rebuttal and possibly include the post in an advanced rebuttal down the track.
2011-03-19 19:06:41
Glenn Tamblyn



This is something I had hoped to post on but life & work always gets in the way. It has always struck ne as a powerful point FOR AGW. Without GH Gases we are a snowball. I actually claimed the post but have had no time to work on it. If you want it, say so.

Basic points AIST.

Faint Young Sun problem and the underlying physics of why - the Standard Solar Model

Tests of the SSM - 100's of thousands of stars, the whole concept of the 'main sequence'

Recent tests of the SSM - the 'neutrino wars' at the turn of the century. Quantum Mechanics had to give way to the SSM.

So, SSM is valid. So something has to compensate for increasing solar output. CO2 declines due to the 'Weathering Thermostat' and the two roughly balance out (very roughly - its a crude thermostat).

So the deep paleoclimate record (500 Myr +) is a strong support of the efficacy  of GH gases. Sun & GH Gases balance each other. Without them we have Snowball Earth and not much life.

To me this has always been one of the knock-out punches for AGW. But like some of the other key evidence, it is not easily conveyed. The key stuff isnb't visceral or immediate - Life is like that. The important is seldom immediate.

The huge holes in the planets OLR spectrum around the CO2 absorption bands.

Changes in these bands.

Delta Total Heat Content of the Oceans.

This is about the basic thermodynamic components