Search Results

This book chronicles almost five decades of efforts by the United States government to reduce the air pollution associated with burning coal, along with the often misleading political rhetoric surrounding those efforts. Given the central role that coal and its environmental consequences will play in our story, it’s helpful at the outset to understand some basic facts about the fuel. Short Answer: A combustible rock. Longer Answer: Coal is a fossil fuel—“fossil” because it’s primarily composed of the preserved remains of ancient plants and “fuel” because it can be burned to create energy. Most of the coal we use today was formed hundreds of millions of years ago when large swaths of the earth were covered in swampy forests. As plant life in these swamps died, it sank to the bottom of the water, where it was eventually buried under additional layers of sediment and slowly decomposed into a soggy, carbon-rich, soil-like substance known as peat. As still more time passed, this peat was further transformed by heat and pressure, a process known as carbonization, into the sedimentary rock we call coal. Short Answer: We mine it, mostly in Wyoming and Appalachia. Longer Answer: There are two basic methods of mining coal: underground mining and surface mining. Surface mining is typically used for shallow coal beds—those buried less than 200 feet deep. Miners access the fuel by simply removing (often with explosives) the trees and soil and rocks that sit atop it. Underground mining, by contrast, is used to extract coal that sits between 300 and 1,000 feet deep. The surface is left relatively undisturbed, and miners dig tunnels through which to enter the mine and retrieve the coal. Historically, underground mining was the more common of these two methods, but today, the majority of U.S. coal is produced at surface mines, which require far fewer workers to produce the same amount of coal. In addition to being cheaper to operate, surface mines are safer: both fatal and serious nonfatal injuries occur about three times more often in underground mines.

Several independent series of observations demonstrate that there has been about 1°C of warming since the start of the industrial revolution. We discussed that there is some variability in solar output, and that these variations may be recognized in records of past climate, but also that solar variability can only account for warming by 0.1°C to an unlikely maximum of 0.35°C since the end of the Little Ice Age. Based on energy balance considerations, we have found that our emissions of external carbon are the main culprit. In response to this disturbance of the energy balance, the climate simply has to change toward a warmer Pliocene- like state, even if we could manage to stabilize CO2 at its current level of about 400 ppm. From discussion of several slowly adjusting processes within the climate system, we now understand that it will take, from the beginning, several centuries to approximate the full Pliocene- like warming. But we are almost two centuries down the road, and warming to date already amounts to about 1°C. The slow components in the climate system will cause continuing warming by another 1°C or so. In other words, we are already committed to further warming, even if we managed to make the massive jump to a zero- emissions society from today and thus stabilize CO2 levels. The urgency of slashing back the current level of annual emissions (10 GtC) cannot be overstated. Every year of inaction brings us closer to the inevitability of a future climate that will exceed even the warm Pliocene state, with global temperatures at least 2 or 3°C higher than the pre- industrial level. If we allow ourselves to reach the Paris Climate Conference’s agreed maximum of 2°C warming by the year 2100, then the further commitment over coming centuries would take us toward 4°C, even if we achieved zero emissions by 2100. That is considerably warmer than during the Pliocene. We have seen that the consequences are grave. Progression toward a Pliocene- like climate state will be accompanied by continued migration of global and regional climate zones and by intensification of the evaporation and precipitation cycle, placing many areas at risk of increasing extremes, including aridity, flooding, and lethal heat.