Perhaps the BEST B1G Forum anywhere, here at College Football Fan Site, CFB51!!!

But I remember a couple of things from that experience that seem to have significance today.  One was that the atmosphere does not act like a greenhouse.  So "greenhouse gasses" is really a misnomer.  Of course, it's just a label, and we use misleading labels all the time.  I don't see any harm to it in this case.  But the second was that CO2 is maybe the least "greenhouse gas-ish" of all the "greenhouse gasses."  It just doesn't trap heat very well.


I think the greenhouse analogy is pretty apt.  CO2 absorbs in the infrared band quite prominently.  This is easily measured and well known.  It is invisible in the visible band (duh).  So, light from the sun comes in and generates heat when it is absorbed by something.  That heat normally radiates back out into space and infrared radiation (IR).  If you "trap" the heat with glass, or CO2, or methane, or something, it doesn't radiate outward as much, and thus is trapped in a greenhouse type affair.

None of this is in dispute.  Without the 280 ppm CO2 we had in the atmosphere, the climate would be quite a bit cooler than it is.  Increasing that to 400 ppm has a pretty easily measured impact on heat retained, and this is less than a tenth of a degree Celsius (°C).  The larger impact is a result of what are called forcing factors, things that happen as a result of slight changes that spiral out of control and amplify the impact.  One simple example is a change in albedo as ice melts.  The planet becomes less reflective and thus warmer.  Another is if permafrost melts and releases a high level of methane trapped there now.

CO2 is not the most effective of the greenhouse gases, but it is by far the most prominent in concentration.  The levels of gases like methane and NOx in the atmosphere are much much lower, Beer's Law and all that come into play.

The models attempt to estimate the impact of those "forcing factors" to make a projection, and this is done by back fitting them to known data in the last.  One problem is that global mean temperature is very difficult to measure.

And all this complexity and more really gets absorbed into the political landscape.  There are very few liberals who don't believe this is an issue and vice versa.  People BELIEVE the way they believe because of their politics, not their scientific acumen.  

My personal best assessment is that it is a serious problem but probably not as serious as it has been hyped by folks like Gore, who I think have done a disservice to the discussion, AND, importantly, there is VERY little we can do practicably to affect this issue.  I don't see a viable real solution, or even significant mitigation possibility.  You can run around yelling wind and solar but that doesn't make it happen, and it won't happen beyond an inconsequential amount.  The best hope might be controlled fusion power, but heaven knows when that may arrive, if ever.

just returned from Texas

it's much warmer there

and it's about 5-10 degrees warmer in Austin than Dallas - better for playing golf in shorts

let's ALL move there

Never gets old...

CincyDawg:

I think the greenhouse analogy is pretty apt.  CO2 absorbs in the infrared band quite prominently.  This is easily measured and well known.  It is invisible in the visible band (duh).  So, light from the sun comes in and generates heat when it is absorbed by something.  That heat normally radiates back out into space and infrared radiation (IR).  If you "trap" the heat with glass, or CO2, or methane, or something, it doesn't radiate outward as much, and thus is trapped in a greenhouse type affair.