OK, imagine you're at the game - the place is packed with one-ninth of a million screaming fans, of which 23,100 of them are rooting for the other team - let's assume the other team is Washington State University (WSU) - they were the visiting team when I took this photo from my Cessna. That leaves most of the remaining 86,900 odd fans rooting for Michigan. The 23,100 WSU fans represent the 21% oxygen component of the atmosphere, with most of the rest representing the 78% nitrogen component. But then there are some oddballs. There are about 3,100 fans who cheer the Michigan cheerleaders - they represent the water vapor component (it's a humid day), and 1,100 fans (the argon component) cheering for the WSU's cheerleaders . But there is one element that has the play-by-play announcers' (the media's) attention, and that's the 43 Hell's Angels who've distributed themselves randomly throughout the crowd. They're just there to make noise.
So... that's our fan base in a nutshell.
OK, here we go.
Michigan scores a touchdown! The 86,900 fans cheer loudly. Hear 'em? They're loud as hell. WSU scores, and their 23,900 fans let out a prolonged whoop. Although it's not as impressive as the roar from the 86,900 Michigan fans, they hold their own as noise makers. Now, there's a time out, and the Michigan cheerleaders are prancing and dancing - you hear a smattering of cheers from their 3,100 fans. The WSU cheerleaders have their turn and their 1,100 fans loudly voice their approval. OK, you're in this big, cavernous stadium, and eleven hundred people can still make enough noise to get noticed by any blind people (the refs) that happen to be in the stadium. But what about the bikers? There's forty-three of them. How much noise do you think they can make in comparison to the 86,900 Michigan fans, or even the 1,100 WSU cheerleaders' fans screaming at the top of their lungs? OK, you get the picture? The upshot of this parable is: out of every 110,000 molecules of air, only 43 of them are carbon dioxide molecules.
Carbon dioxide currently makes up 0.039% of the atmosphere. That's thirty-nine thousandths of one percent. It's a greenhouse gas, to be sure, but as a greenhouse gas it's only about 20% as potent as water vapor. So, on a humid day, when when the air contains about 2.8% H2O, the humidity constitutes 99.7% of the greenhouse effect.
What everybody's worried about is that 1/4 to 1/3 of one percent (0.3 %) of greenhouse effect driven by carbon dioxide is heating up the planet enough that there will be more humidity and thus more greenhousing by water vapor which will warm the planet up even more and make more water vapor and heat the planet up even more... - it's called a runaway greenhouse effect. There's another concern that that 0.28% greenhouse effect by carbon dioxide will turn into 0.56% and then 1.12% and that will lead to more humidity that will in turn lead to more warming and so on and so on and so on.....! It could happen! (But probably won't). Nobody really knows for sure. But what irritates me is that the apocalyptics are playing Chicken Little - they're pushin' too hard on me and a lot of other people to warrant any credibility. It's like, whoever makes the most noise gets the attention, you know, the squeaky wheel, but it's not good attention.
Richard Lindzen is an atmospheric physicist at the Massachusetts Institute of Technology (MIT) and is widely considered at the top of the heap of atmospheric scientists. In 2009 Dr. Lindzen co-published a paper with Yong-Sang Choi, a young graduate assistant, in the journal Geophysical Research Letters known as LC 2009. In this paper Lindzen and Choi argued for a much smaller climate sensitivity parameter, called lambda (l), than the "official" IPCC-sanctioned value based on an increase of temperature falling within a range 3° C to 4.5° C if the atmospheric CO2 concentration were doubled. According to the IPCC, the value of l then, is between 0.8 and 1.2. The LC2009 paper suggested the real value for l was 0.04, which translates to a rise of global temperature of only 0.15° C with the doubling of CO2. That's only 1/20th to 1/30th of the "official" IPCC line for the doubling of CO2. As expected, their paper elicited a howl of protest from the apocalyptics. Almost immediately an army of global warming proponents rushed to publish rebuttals and try to discredit LC2009.
As physicists, Lindzen and Choi employed quantum mechanical principles as a foundation of their work - they predicated their study on the quantum mechanical behavior of the CO2 molecule when it gets hit by quanta of long wave (infrared) radiation trying to escape into space. Below is a chart based on their work.
According to these graphs, we are not heading towards a global catastrophe. Again, these charts are derived from the physical traits of the CO2 molecule (which is better depicted as OCO, or better yet, O=C=O) insofar as it's ability to trap long wave radiation in the earth's atmosphere. This is because when a CO2 molecule gets hit by a quantum of longwave radiation, wiggles and wags for a micro-second or two before emitting the quantum (or photon, if you will) at a slightly lower energy level and returning to its ground state. Its linear structure and stable double covalent bonds limit the number of frequencies that can affect it to only 3 relatively narrow bands (2.7, 4.5, & 15 microns). There's a formula with which the modes of vibration, or "degrees of freedom" of a given molecule can be affected by longwave radiation. That formula is simple: 3n-5, where n is the number of atoms in a given molecule. With CO2, there are three atoms, two oxygen and one carbon, so one could assume that 3 X 3 - 5 equals four degrees of freedom. One of those degrees of freedom are invalid with CO2, so the CO2 molecule has only three degrees of freedom to vibrate (absorb longwave radiation). That's why as far as greenhouse gasses are concerned, it's one of the weaker ones.
Another factor to consider is that as the concentration of CO2 increases, the absorbtion bandwidths DO NOT increase, only the amplitude increases (up to a point - ca. 915 ppmv). What this means is that outgoing longwave radiation is absorbed closer to the surface of the earth. Rather than being almost completely absorbed say, within the first kilometer of the lower atmosphere, the lion's share of outgoing radiation gets absorbed within say, a half-kilometer of the earth's surface. While it may yield slightly higher night-time temps within the lowest levels of the atmosphere, this effect is NOT cumilative. As soon as the sun comes up and visible radiation heats the surface of the earth, the slight increase in temperature in the lower atmosphere from overnight gets completely overwhelmed. Another thing to consider is that outgoing longwave radiation occurs only at night. Again, after the sun comes up, all the longwave radiation gets obliterated by the sunshine that is now heating the earth directly.
As stated above, once the concentration hits about 915 ppmv, OCO completely runs out of steam (Myrhe et. al. 1998). It's called saturation, or activity extinction, where additional CO2 concentrations have little to no effect. Think of a large bell. Tap it with a hammer and it will ring. Hit the bell a little harder and it will ring a little louder and keep ringing longer. Hit it harder yet and it will ring even louder and longer. But there comes a point when no matter how hard the bell is struck, it won't ring louder or longer beyond that point. The bell has reached a saturation point.
Are Lindzen, Myrhe, and other scientists correct? I guess time will tell. All scientists who study complex systems like climate can do is offer their opinions and educated guesses. That goes for both sides of the AGW issue. We run into problems when scientists, who are, after all, foibled human beings, interject their personal opinions and beliefs into what is supposed to be a dispassionate pursuit of the Truth. And where we run into BIG problems is when politics gets involved that directs scientists to misuse science in pursuing political mandates rather than pursuing and/or finding real answers to difficult questions.
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