A recent comment on my weather and climate pet peeves post called me a curmudgeon. While this characterization is probably accurate, the poster went on to say, “what did you do to influence 500000 people today?”

While it’s an interesting thought about what I would say if half a million people listened to me, I have no doubt that it will forever remain academic. However, I also reject the implication that the subject of that particular peeve has a daily reach of 500,000. His highest viewed video on YouTube has a little under 600,000 views total at this time. So unless he posted the videos yesterday (he didn’t), he cannot have a daily reach of half a million. The video was posted in June 2007, which means that an average of about 3300 people see the video each day. Just a couple orders of magnitude different than 500,000. (It’s still at least one order of magnitude larger than my reach, but who’s counting.)

Anyway, with 3000 people watching this video per day, does he at least get his facts right? The not-surprising answer is no.

Let’s take a quick look at How It All Ends: Mechanics of GCC (pt 1 of 3) - one of his lesser viewed videos, but one that attempts to deal with the science. Below are some quotes from the video, with my responses. (Apologies if I misquoted something. There was no transcript, so I had to listen repeatedly and transcribe it myself.)
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Yesterday I was messing around with the NCEP/NCAR Reanalysis and decided to plot the time series of the global mean temperature. This can be seen below in black. I then ploted the GISS temperature, in purple(?).

As can easily be seen, the temperatures from 1948 through 1980 track each other very well. However, at this point they start diverging. The temperature calculated by GISS rises at a higher rate than that from NCEP. I haven’t done any statistical tests on the rate of increase in temperature.

Which of the two temperature trends is correct?

The title of this post would suggest that I don’t think that 1990s CO2 emissions are a good target. Actually, I don’t have a problem with them - I trust the experts in this matter. However, what I don’t think is good is the US governments continued push that developing countries “share the load”.

One of the most frequent arguments I hear as an excuse not to reduce carbon dioxide emissions is that it will harm the economy. To zeroth order, it probably is a good guess. Any sort of restrictions that limit the carbon dioxide emissions (whether through a carbon tax, or cap-and-trade) will necessarily lead higher prices initially. I’m not an economist, but this is where they loose me. Higher prices do not necessarily lead to a decline in the economy. If that were true, the countries with the lowest prices (developing countries) would have the best economies. But that’s simply not true. There are many factors that determine the strength of the economy.

Therein lies the problem: developing countries need to be given the same opportunites as developed countries. This means that setting CO2 limits, the number of people in the country needs to be taken into account.
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Last summer my mother visited me, and I took her to Kitt Peak for their nightly observing program. I would highly recommend this to anyone visiting the Tucson area. She seemed to really enjoy looking at the stars and learning about them. For Christmas this year I bought her Bad Astronomy by Philip Plait. The good thing about buying someone a book is that you get to read it before sending it away. I’m only through the first few chapters, but it’s a good read so far.

Anyway, back to the topic at hand. What color is the sun? Phil tackles this question in his book, but I’m going to comment here as well. I’ve been asked this question a few times, but mostly I like asking it to others. The reason? Because it doesn’t have an answer. Pretty much any answer given will be correct - unless you’re Sean Connery on Celebrity Jeopardy. The actual answer to the question doesn’t really matter, it’s the follow up - explaining that the sun doesn’t produce just one color, it produces lots of colors.

Below is the solar spectrum (courtesy Global Warming Art, see linked page for copyright information). The yellow “curve” is the radiation from the sun that is intercepted by the Earth at the top of the atmosphere. On its way to the ground, some of the radiation is absorbed or scattered. The amount of radiation we see at the ground is the red “curve”.

What does this mean in terms of the question posed above? Well, as long as the person answering gives a color that corresponds to a wavelength between 250-2500+ nanometers they are right. My answer to the question of the color of the sun is always the same: green.

People always look at me weird when I say the sun is green, and I understand why. If you answer that the color of the sun is yellow or white people will think you’re normal. That’s because the sun does look white or yellow. But look again at the solar spectrum above. The peak is about 500nm. Do you know what color that is?

According to this page from North Carolina State University (from whence the table is derived), 500 nanometer light is blue-green! Actual 500 nanometer light is actually more green than the color of the font in the table. To me, it appears almost like the color used in the clocks on microwaves. Since I describe that color as green, I therefore describe the color of the sun to be green.

Of course, this doesn’t actually mean the sun appears green. I just went outside and looked. The sun still appears white. Don’t look directly at the sun! Ever! The reason the sun appears white is that the sun produces light in all the visible spectrum. And when those differently colored wavelengths of light are combined, they produce white - the opposite of shining white light through a prism.

The moral of the story? If some wiseass asks you what color the sun is, beat him/her to the punch and say it’s green.