Bethell vs Mooney

Perhaps you need to update (and keep updating [daily?]) your bingo game to account for "Global Warming Skeptic Argument Drift" (GWSAD). Some skeptics have caught on to the game -- figured out that they need to evolve or simply go extinct.

It's very frustrating when I keep looking for a spot to cover for the latest Skeptic argument and I find its not on the sheet.

Like this one: "Yes, yes, yes, Global warming is real, but how much have humans contributed to it? That's the REAL question. More research is needed"

Or this one: "Relax. Global warming is actually good."

Bethell did ramble on far too long, but I thought Chris's rebuttals were all the more sweet for being swift and concise.

Or maybe you could make a "Bonus Box" on the bingo game that would allow for GWSAD (ie cover the latest vaccuous argument).

I don't think this "debate" settled a single solitary thing. Too many topics, too little scientific expertise.
http://davidappell.blogspot.com/2006/06/bethell-vs-mooney.html

How about updating it every 6 months, Tim? Shouldn't be too much work, and I'd expect it would be very popular and useful.

but Coby Beck takes care of it here.

Takes care of nothing.

See my unanswered comments on that thread.

I don't think so nanny. You actually deny that the CO2 forcing was less in the 50s. The CO2 concentration was less then, so the forcing was less.

Here's an idea for keeping your Bingo board up to date.

Perhaps you could create a webcrawler that visits well-known "GW Skeptic" sites and automatically looks for changes/additions to their "global warming myth" page. You could also have it automatically linked to the Bingo board in order to keep it refreshed with the latest and greatest "anti-global warming" argument.

I know some of the sites have not been updated since the last ice age, but a few make a feeble attempt to change a few things on their site now and then to make it look like they are abreast of the latest (last 10 years, at least) research.

Tim, have you no other comment on my other points which are far more relevent to the mid-century cooling discussion?

You actually deny that the CO2 forcing was less in the 50s.

I think you've mis-read my post.

The CO2 concentration was less then, so the forcing was less.

But it's the change in forcing that we're concerned with, not the concentration of CO2. More IR will be trapped per unit of CO2 at lower concentrations than at higher. That's my understanding, anyway. So was the change in CO2 concentrations during the mid-century trapping more or less IR compared to today? I don't know, having not done the math. That's why I asked "Are you sure?" because it seems that some justification is required for Coby's statement.

But it's the change in forcing that we're concerned with, not the concentration of CO2. More IR will be trapped per unit of CO2 at lower concentrations than at higher. That's my understanding, anyway.

Whoopsie.

Best,

D

"That's my understanding, anyway."

Then your understanding is frighteningly deficient.

CO2 molecules absorb infrared radiation in specific parts of the spectrum.

It's a molecular level event which can be measured in any high school physics lab and it is completely unrelated to the overall concentration of CO2.

The forcing is goign ot be linear up until the point where the CO2 IR window is closed - i.e. all or virtually all radiation at the frequencies absorbed by CO2 is being blocked.

I'm pretty sure that the effect of CO2 on temperature is logarithmic. I've seen such stated in the IPCC TAR.

I'm not sure, na_g_s, how this addresses anything Ian or I said, other than it doesn't.

Best,

D

It's a bit complicated, but here is some basic information on how absorption of light works. Molecules like CO2 (or atoms, or ions - I'm an astronomer) can only absorb specific frequencies of light that correspond to transitions between different energy levels, at least at terrestrial temperatures. Consider a small concentration (or a weak spectral feature). Some of the light emitted is absorbed; the probability of absorption is a product of how likely the relevant transition is and how many absorbers there are. This is an exponential process; the fraction of the light that gets through is

exp(-tau) where tau is the optical depth. When tau is small, the response is linear (double the concentration and the fraction that gets absorbed doubles). When tau is large, you get diminishing returns; the difference between tau of 10 and 20 is small (e^-10 or e^-20 gets through).
This explains why CO2, methane, etc. are important even though there is much more water. There is so much water that it effectively absorbs almost all of the light that it can.

For a global problem, you have to consider other factors. Light from the Earth can escape at some wavelengths but not others; how easy it is for the light to get out at other wavelengths affects how much of a greenhouse effect there is.

You also have to worry about what happens to the absorbed light (it can be re-emitted in a random direction or the molecule can collide with another one, heating up the air.) As CO2 goes up, strong features saturate but weaker ones get important. Eventually CO2 will fully saturate and increased concentrations won't block any more light, barring phenomena like dense clouds (e.g. Venus).

Ian, the forcing from CO2 is logarithmic -- that's why they talk about climate sensitivity to doubling CO2 rather than to increases in absolute numbers. However, at current concentrations there is little difference. For example, you get 50% of the 2XCO2 forcing from an increase of 41% in the concentration (sqrt 2 - 1).

So nags is correct to say that the response is logarithmic, but it doesn't make the difference he thinks it does.

I see how the discussion on this thread has quickly shifted from the mid-century cooling in the face of rising CO2 emissions to a discussion of CO2 IR absorption theory. I'll try to get it back on track...

but Coby Beck takes care of it here.

Takes care of nothing.

See my unanswered comments (plural) on that thread.

So let me see if I now understand the situation.

The temperature response to increasing CO2 is logarithmic because eventaully you hit a point of diminishing returns where additional CO2 has a declining impact on temperature due to the closing of the CO2 absorption window.

But at current atmospheric levels the forcing is so similar to linear that the divergence makes little practical difference?

na_g_s:

I see how the discussion on this thread has quickly shifted from the mid-century cooling in the face of rising CO2 emissions to a discussion of CO2 IR absorption theory.

It's more about methods of dissembling.

But anyway, you are trying the Googler technique of looking at a graph and saying 'a-ha!!!!'. That don't cut it.

"Your" "argument" (and ohsobrilliant cut-pasted questions) on Coby's site only tries the aerosol-CO2 gambit. There are many things going on here that could be at play, including land use changes and oceanic heat storage. Discuss them, don't cut-paste from see-oh-too.

We know, from the link I gave you that corrected your erroneous argument above, that forcing is increasing, so where did the energy go? That's the question.

What you'll want to do to try to make your argument look cogent and valid is trot out some alternative testable theories. Do the septics have any? If, by chance they've come up with some by now, trot 'em out. Share.

Propose an alternative to the typical septic scrunching the eyes closed real hard, little foot stomp conspiracy theory stuff.

Thanks!

D

"Your" "argument" (and ohsobrilliant cut-pasted questions) on Coby's site only tries the aerosol-CO2 gambit.

That was the subject of the thread. Here's Coby's claim: "The situation is similar to the cooling seen in the 40's and 50's. During this period the CO2 warming (a smaller forcing at the time) was temporarily overwhelmed by an increase in human particulates and aerosol pollution."

There is no mention of "many things going on here that could be at play", just aerosols and particulates overwhelming CO2.

We know, from the link I gave you that corrected your erroneous argument above, that forcing is increasing

Your link, while interesting, is entirely beside the point. It doesn't cover the period of time in question and it doesn't report aerosol forcing.

With regard to my "erroneous argument" I said "More IR will be trapped per unit of CO2 at lower concentrations than at higher" which is true as far as I know and your link does nothing to counter it.

trot out some alternative testable theories.

I don't know if it is testable, but here you go Dano:

We don't really understand the effect of increased CO2 concentrations on global climate.

Have a good day.

Yep, Nanny, not only has the atmospheric concentration of CO2 increased since 1950, the forcing from the concentration increases has increased http://tinyurl.com/q7fa7, and the rate of increase of the forcing has increased http://tinyurl.com/z645g. Want to go for the third derivative?

>We don't really understand the effect of increased CO2 concentrations on global climate.

You don't know the answer (though most experts think they do) so you think we should all embark on a stupid experiment. Buckle up for the ride whether we like it or not. Very clever Nanny....... NOT

Nanny knows better than the experts because his political beliefs (obvious from his username) tells him what the correct scientific answers are.