A well-illustrated
article by NASA's Earth Observatory discusses the issue of coal mining in Appalachia. Estimates are that we have 100 years or more coal reserves in the world -- far more than oil. The problem is, coal is dirty. Appalachian coal in particular is high in pyrite (FeS
2), so that when it is burned, sulfuric acid is generated.
And then, of course, there is the issue of greenhouse emissions. When we heat or get electrical power from the burning of coal, we are reversing an ancient photosynthetic reaction. In the Carboniferous, great swampy deltas (much like the modern Mississippi Delta) stretched across what is today West Virginia. Great rivers draining the young Appalachians flowed west into a shallow epeiric sea. In these muddy deltas, plants grew in profusion. Those plants did what modern plants do: they sat in the sunlight and used its energy to fuse CO
2 and H
2O into sugars -- plant food. Before they got a chance to use that constructed food, and before any animals had a chance to eat the plants, they were smothered beneath additional layers of sediment, and the efforts of their photosynthesis were locked away underground. This went on for millions and millions of years. Now, humanity has discovered that coal burns well, releasing energy originally generated by the Sun 300 million years ago. Using coal for energy reverses the ancient photosynthetic reaction. When we burn coal, we are combining the coal's "carbohydrates" with oxygen, and re-producing the initial ingredients (CO
2 and H
2O) in the process. Of course, when water vapor in the air reaches a high concentration, it condenses and precipitates. Carbon dioxide is also removed from the atmosphere by geologic processes, but at a much slower rate. Hence the
rise in atmospheric CO2 levels since the Industrial Revolution (when coal-burning picked up pace).
The
Earth Observatory article deals with another issue, though: the question of how best to get at coal, given that it's underground in strata with other rock layers atop them. Every month, it seems like there is an item in the news about how there's been an accident in some underground coal mine somewhere in the world, always with a dozen or more miners killed or trapped. In West Virginia, strip mining is a favored tactic. It's safer to coal miners because it occurs at the surface, but there's the rub: The surface is also where everything else happens, too. When miners strip away the overlying rock layers, they also strip away the forest and everything that lives there. Often, unwanted rock is dumped into neighboring valleys, which causes a lot of stress on the freshwater ecosystems present in streams draining that valley.
Check out the article
here. It is illustrated with great maps and satellite photos.
Labels: CO2, coal, global warming, mining, satellite imagery
This map was in this morning's Washington Post. The red dots are currently-existing coal-fired power plants. The black dots with the central stars are proposed future coal-fired power plants. 