There are many questions one would like answered. These may include “what is the meaning of life?”, or “why don't they make the airplane out of the airline food?”. These are certainly important questions, but perhaps not at the level of “what's the deal with carbon?”. When it comes to environmental issues, it's difficult to avoid hearing something about carbon. Carbon dioxide, carbon cycle, carbon dioxide equivalent, carbon dioxide fertilization, carbon footprint, carbon sequestration, carbon capture, carbon tax, tax on carbon, price on carbon, (any way to say carbon tax without “tax”), chlorofluorocarbons, chlorofluoroclintons, and so on. Well that's all well and good, but what does it all mean? I don't know. I figured that some research was called for.
Specifically, I was interested in the idea of carbon dioxide as a so called “greenhouse gas”. This term is somewhat inaccurate, but I won't dive into that right now. It seems as if a lot of people know the following: carbon dioxide is released excessively from burning fossil fuels and other human activities (such as deforestation), and it builds up in the atmosphere somewhere and traps heat inside. But how do gas molecules increase global temperatures? And why is everyone obsessed with carbon dioxide? Don't other gases like water vapour have the same effects? So many questions and so much time.
First, it turns out that carbon dioxide gas makes up a small fraction of the air. Another “greenhouse” gas, water vapour, actually contributes to about half of the so called greenhouse effect. Considering this, one might think that we should just stop boiling potatoes, but it's not quite so simple. Unlike water vapour, carbon dioxide is a non-condensing greenhouse gas. Essentially, this means that while water vapour cycles quickly and does not build up, carbon dioxide hangs around. Approximately one fifth of the carbon dioxide in the atmosphere at the moment will still be there in 800 years. That is a long time. Thus, carbon dioxide is the the gas that runs the show.
It was nice to have this cleared up, but I still wanted to know more about the mechanism of the whole process.
Have you heard of the sun? Well I haven't. So the sun tends to send to earth a nice variety of electromagnetic radiation. Close to 40 % of this radiation is lower in energy (longer wavelength) than visible light. A good percentage of this is infrared. The planet absorbs and radiates this stuff back out. Interestingly, the earth is somewhat cold compared to the sun, and so the stuff coming back disproportionately consists of the low energy/infrared kind. Carbon dioxide and other gases are particularly good at absorbing infrared. Alright, so at this point I could stop right? No, there is more.
How does a molecule of carbon dioxide actually absorb this energy? Differences in chemical structure and bonding result in different absorptive abilities. My analogy goes as follows: Brezhnev has thick eyebrows, while Thatcher doesn't. Thus, the organisms that burrow inside eyebrows will be absorbed more by Brezhnev than by Thatcher. When the energy/wavelength fits, the carbon dioxide molecule will vibrate, and absorb energy. Through this vibration, heat is released.
With the details out of the way, I wanted to look at the big picture. Why is something like deforestation such a large issue? The key problem here is that a forest is a carbon sink; something with a net gain in carbon. Yes carbon will be released from a forest due to cellular respiration, decomposition, and pontification, but overall more carbon is absorbed through (in the case of a forest) photosynthesis. Cutting down forests releases carbon into the atmosphere and halts absorption. It's an utter mess. But there is hope, and there are ways to help.
First off, plant trees. Trees are large organisms that photosynthesize extensively and absorb carbon dioxide gas. Second, plant other plants. Same idea. Third, manipulate someone wealthy into buying a large chunk of land and plant trees. Fourth, manipulate someone wealthy into buying a chunk of a forest, and keeping it as a forest. However, some of this may be hard to do, so you can always make your own carbon sink. That is for next time. Thank you for reading. Check out these sources where I found most of my information.