Comment Re: Are they really that scared? (Score 1) 461
You simply aren't reading my posts. It's not "CO2 emissions aren't a concern"; it's "CO2 emissions aren't a concern if all you use is high school physics". It's all explained above.
Nobody here is only using high school physics. I just showed that my explanations of the greenhouse effect match that of Ray Pierrehumbert, author of Principles of Planetary Climate. (Just in case you've never heard of this textbook, it isn't a high school textbook.)
It's disappointing (but sadly not surprising after meeting Sky Dragon Slayers like Jane) to find that lgw can't or won't cite even a single peer-reviewed study of equilibrium CO2 climate sensitivities that he actually accepts. And, frankly, ocean acidification is pretty close to being high school chemistry. Does lgw dismiss ocean acidification like Jane and the Sky Dragon Slayers do?
At combustion-chamber temperatures, CO2 actually reflects infrared, vs absorbing it, which is a much more dramatic effect.
There are two way in which CO2 interacts with IR radiation:
1) It can absorb IR, becoming warmer, and in turn emit IR as a blackbody.
2) It can reflect IR.
The energy transferred by effect 1 depends on the temp of the CO2. The energy transferred by effect 2 depends instead on the temp of what's being reflected. As these are "4th power of temp" effects, the difference is critical.
If this is such a critical and dramatic effect, you should easily be able to cite peer-reviewed articles (other than G&T) supporting and quantifying it. Right?
Saying "but what about Venus" gets the physics wrong (and also implies that the Earth could somehow one day become like Venus, when there's no mechanism for that).
No, I've actually emphasized that:
"I'm not saying that the Earth will turn into Venus. That would be absurd. We have no reason to think that the 'runaway greenhouse' on Venus is even possible on Earth."
Rasmus Benestad and Ray Pierrehumbert agree:
"The Earth may well succumb to a runaway greenhouse as the Sun continues to brighten over the next billion years or so, but the amount of CO2 we could add to the atmosphere by burning all available fossil fuel reserves would not move us significantly closer to the runaway greenhouse threshold. There are plenty of nightmares lurking in anthropogenic global warming, but the runaway greenhouse is not among them."
CO2 plays a role in absorbing a small percentage of the IR that is not reflected (which is itself a small percentage of the heat loss from the surface), and becoming warmer. The increase in blackbody radiation from the warmer CO2 is trivial. Thinking of this as "look, simple physics at work here" gets it wrong.
I've already explained complex factors like pressure broadening, which don't change the fact that CO2 warms the surface. For instance, how would surface temperatures change if all the CO2 in the atmosphere suddenly vanished? Sky Dragon Slayers have a simple (and wrong) answer: it wouldn't. What's yours?
Most of the heat transfer away from the surface of the Earth is by convection - radiative heat loss is a small effect by comparison.
I've explained that to a first approximation, convection establishes the lapse rate (the rate at which temperature drops with altitude in the troposphere). That establishes the slope. Adding greenhouse gases increases the effective radiating level, which increases the "y-intercept" of the temperature vs. altitude line. Both are necessary to determine the surface temperature (along with the Sun's brightness and the Earth's albedo, etc.)
If you think the process is simple and obvious, that just means you don't understand it. If you believe it without understanding it, you're acting on faith, not reason, regardless of your choice in high priests. Don't do that - either study the subject, or admit it's not important to you.
By "study the subject" do you mean reading crackpot websites, or getting physics training from an accredited university, leading to a physics PhD and a career studying Earth science? I ask because I've wasted years "talking" with anonymous internet ninjas who lack the physics training to even recognize that they lack physics training. Since you know my name and my physics training, what's yours? Knowing your physics training will help me calibrate my explanations to your educational background.