I thought this was going to be an interesting paper: Direct and indirect effects of anthropogenic aerosols on regional precipitation over east Asia in the most recent JGR. It turned out to be not so interesting, at least for me, as I’ll describe later.

Abstract: A regional coupled climate-chemistry-aerosol model is developed. It is used to assess the direct and indirect effects of anthropogenic sulfate and carbonaceous aerosols on regional climate over east Asia with a focus on precipitation. The simulated direct and first indirect effects for the most part reduce the solar radiation and hence decrease the surface temperature, while the second indirect effect generates both negative solar forcing and a substantial positive long-wave forcing. It decreases the precipitation, but because of the cancelling effect, surface temperature does not change very much. With the interactively model-calculated current aerosol loading and the combined direct/semidirect/first indirect effect, the simulated precipitation is reduced by about 10% in the fall and winter and by about 5% in the spring and summer. The second indirect effect has the largest impact, by itself decreasing the fall and winter precipitation from about 3% to 20%, depending on the autoconversion scheme assumed. The semidirect effect on precipitation is relatively small. An empirical orthogonal function analysis of climatological precipitation over east Asia since the last century shows a decreasing trend of the leading modes over most of China in the fall and winter, which is generally geographically consistent with the distribution of the model-simulated precipitation reduction from anthropogenic aerosols.

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In a partial response to Tamino: Question for Believers

So, IF AND ONLY IF you believe that AGW is true (i.e., that global warming is happening as a result of human activity), then: What would change your mind?

The accepted theory is that greenhouse gases warm the surface of the Earth because they are radiationally inactive to incoming shortwave solar radiation, but radiationally active to outgoing longwave Earth radiation. Yes, that’s simplified a little… or a lot. If the solar output is relatively constant and assuming thermodynamic equilibrium, then the total incoming energy needs to equal the total outgoing energy. I’m assuming the solar constant has been in fact constant over the last couple hundreds of years. I think this is true, but don’t know for sure. Also, if there is any warming or cooling of the surface or atmosphere, then the Earth is not in equilibrium. Thus, this only strictly applies to before and after any changes occur. But it doesn’t really matter, because it still needs to apply at the endpoints, which would be in equilibrium.

If the surface of the Earth is warming, then the upper atmosphere must be cooling. This must be true from a simple energy conservation argument.

The data on temperature in the upper atmosphere is a little ratty. As far as I’m aware, there is no single long-term data source that provides temperature measurements of the meso- or thermosphere. Any pointers to such data would be great. However, there are recent papers that do purport to be finding a cooling in the upper atmosphere, such as Global Change in the Upper Atmosphere in the journal Science.

Getting back to the original question, in order to change my mind I would need to see peer-reviewed papers that find no change or an increase in the upper atmosphere temperature. Because without an upper atmosphere cooling, there is no surface warming.

I’m sure there would be other things that would change my mind as well. But a warming of the upper atmosphere would be a slam dunk.

Yes, it’s been a few days since posting. I’ve been busy grading. Boooo.

Okay, so everyone should know that by adding a number to a set that is greater than the mean of said set will increase the mean. But I wasn’t sure I could prove it. Well, I did. And here it is. I did it by contradiction, but there’s probably a more straightforward approach too.

Meaning of variables:
xib = initial mean of i values
xi = ith value in x
xj = jth value in x (new value added)
N = number of values
xfb = final mean of i+1 values

Assume xj > xib means that xfb < xib

xib = sum(xi)/N
xfb = (sum(xi)+xj) / (N+1)

If xfb < xib then
(sum(xi)+xj) / (N+1) < sum(xi)/N
(sum(xi)+xj)*N < sum(xi)*(N+1)
N*sum(xi)+N*xj < N*sum(xi)+sum(xi)
N*xj < sum(xi)
xj < sum(xi) / N
xj < xib

Which is in contradiction to the initial assumption that xj > xib. Therefore, xfb > xib.

(Wouldn’t this look a lot prettier using LaTeX?)

I had a previous post title Google Oops, and since I pointed out that folly, I may as well point out that I too make mistakes. Though hopefully not too often, except for grammatical ones.

Now, I admit that I made a mistake in NASCAR Contribution to CO2 Emissions. My mistake was that I couldn’t use a calculator. I don’t think that there was anything wrong with my methodology. It was just a quick order of magnitude calculation. My new results, as shown in the comments of the previous post were

[NASCAR uses] 477,300 gallons of fuel used per year… the mass of CO2 emitted by the 3 major NASCAR events (NEXTEL Cup, the Busch Series and the Craftsman Truck Series) for the year totals around 4300 metric tonnes. This still amounts to only 0.0000017 percent of total emitted CO2.

After a quick search on the Internets, we see that NASCAR estimates its total fuel consumption for a weekend at 6000 gallons. [1] Not much different than my estimation of 4300 gallons. And that another estimate out there puts the total fuel consumption by NASCAR in a year at 2,000,000 gallons. [2] Again, not that different than my estimation of 477,300 gallons. (A factor of 4 is not that big considering the assumptions I made.)
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