Global warming has been a thorny issue for me for quite some time. The problem has been that while I believed that the earth is warming and that humans played a part in it, I never understood the mechanism by which it operates, and my conviction has been limited by the resistance to acknowledging it by many people. Because I didn’t understand it myself, it was hard for me to talk about global warming with a lot of confidence.

That was before I read the article, The Case of the Missing Carbon in the February National Geographic. I really wish the whole article were posted online because it provides the most concise and sensible explanation of how global warming actually works that I’ve read anywhere. In fact, I think that after reading it I could explain global warming to anybody in one paragraph in a way that they could understand, and I’m going to give it a shot, just for practice.

The first thing to understand is that the amount of greenhouse gases in the atmosphere dictates how much heat the atmosphere can store. The more carbon, methane, and other greenhouse gases are in the air, the hotter it is. Various natural processes release carbon into the atmosphere and leech carbon out of the atmosphere. For example, when the leaves that fall from the trees decay, they release the carbon stored in them into the atmosphere. In fact, the vast majority of carbon that’s released into the atmosphere gets there due to basic natural processes that are beyond our control. The main methods by which carbon is removed from the atmosphere are photosynthesis and absorption by the ocean. If more carbon is released into the atmosphere than these natural processes can soak up, then the overall level of greenhouse gases rises and thus the atmosphere is able to store more heat, leading to global warming. Throughout history, natural processes have led to a lot of carbon being stored rather than being released into the atmosphere, specifically in the form of fossil fuels. Rather than decaying, much organic matter has been trapped within the earth, and converted into oil, gas, and coal. Human beings have been taking this stuff out of storage and burning it, and the natural processes that absorb carbon have not been able to keep up with this increase carbon release due to the burning of fossil fuels and so the overall level of atmospheric carbon has risen, thus giving way to global warming.

When combined with the empirical evidence we do have, the anecdotal evidence I’ve read about (mainly coming from northern latitudes), a basic understanding of how the process actually works leads me to believe that there’s not much room for doubt of global warming and our part in the process. As of breakfast this morning, global warming has suddenly become a much bigger political issue for me.

One thing that’s obvious is that no Bush administration is going to do anything about it. They’re exploiting the fact that scientists are basically humble to repeatedly send it back for “further study.” It seems to me that one of the most obvious steps we can take is burning less carbon. Coal is the worst offender in this regard, and I kind of wonder whether nuclear power looks better in light of global warming. Nuclear waste is a huge problem, but it seems to me that global warming is a larger long term problem. Another simple step we can take that Republicans have resisted is raising fuel economy requirements for cars. The only reason not to do so is love of large cars and love of oil companies. The reasons for doing so are myriad. Lowering carbon emissions is a huge reason to do so, but there’s also the advantage of lowering our dependence on oil imports, and the fact that Americans will save money on fuel and die less frequently in car accidents.

One interesting part of the article that’s less easy to summarize is the experiments that scientists have done to figure out which natural processes are doing the most to remove carbon from the atmosphere, and how we can boost the environment’s ability to absorb more carbon. One interesting factoid was that old growth forests are not great consumers of carbon. The best habitats for absorbing carbon are forests that are growing, like those in the eastern United States that are only a few decades old. It seems to me that these findings should cause us to think differently about forest management.

Needless to say, global warming is much on my mind right now. Expect to see more about it in this space.