Last week I posted Dan Kuttner’s 11 points titled “Some questions on the science behind Global Warming.” The idea being these 11 points seriously bring into question the validity of the science behind anthropogenic global warming (AGW). Dan is of a conservative bent, and a theme running through American conservative politics is that AGW is hoax science. I will not rehash any motivations conservatives may have for leaning in that direction; that is for another day. I will address Dan’s point number 1:
How does CO2, which is 1.4x heavier than air at sea level, get above the troposphere to cause a greenhouse effect?
I am one of those who contend there is no such thing as a stupid question. There are exceptions. This question is worded in the worst possible way. First off, whoever composed it confuses “heavier” and “denser.” Carbon dioxide does, itself, not have a weight, but it is denser than air. If air has a density of 1.00 on some scale, then carbon dioxide has a density of 1.53 (my first-order calculation). So even if point 1 meant to say “denser” it would have still been wrong. This is an example of the logical fallacy called “begging the question.” A question is posed with a premise pre-loaded.
And while I am being pedantic, 1.4 times heavier is not the same as 1.4 times as heavy as. 1.4 times heavier is 2.4 times as heavy as. It’s the English language, folks.
Now for the second part. Granted that carbon dioxide is denser than air, how does it get above the troposphere? Dan is a qualified airplane pilot, and one the things taught in pilot training is atmospheric science. From that he should have learned that gases in the troposphere are fairly well-mixed by atmospheric turbulence. The concentration remains abut 400 parts per billion by volume throughout. In truth, I found no figures for carbon dioxide in the stratosphere, but there is no reason to believe the gas does not propagate to that region.
But here is the sticker. Dan’s question is again loaded. The premise is that carbon dioxide needs to get into the stratosphere to have an effect on global warming. The fact is that the vast bulk of the atmosphere is in the troposphere, and also it matters little at what altitude carbon dioxide is encountered. It absorbs infra red radiation at any altitude, and it is particularly effective in the lower regions, close to the ground. Energy absorption by carbon dioxide warms the atmosphere close to the ground, keeping the surface warm and causing the surface to absorb the trapped energy. The oceans particularly become warmer by this process.
And that should answer Dan’s spurious question regarding carbon dioxide in the troposphere and the stratosphere. The next post in this series will address Dan’s point number 2. Keep reading.