The term Anthropocene is increasingly used to designate the period of Earth’s history during which humans have assumed a leading role in planetary change, beginning about 1850 C.E., when fossil fuels became the dominant energy source. Given humanity’s compounding impact on the environment over time, studying the effects of human activity on the Earth has become a cornerstone of climate-change research. The spread of global warming has become so pervasive that human activity increases its speed in what were once unexpected ways, exemplified by the spread of ashes across previously bright white ice and snow in high mountains and glaciers, diminishing their reflectiveness and advancing thaw. The melting of ice also yields a darker ocean surface, which accelerates rises in temperature. Even processes that are not often thought of as contributions to warming, such as the green revolution in agriculture, may play a role. Notable references that address the Anthropocene include “The New World of the Anthropocene” by Jan Zalasiewicz et al., “Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes” by Morris A. Bender et al., and “Water and Climate: Recognizing Anthropogenic Drought” by Amir AghaKouchak et al.
However, fossil fuels have not always been required to bring about the disintegration of an important and apparently stable political and economic system. Witness the Maya, who fell into an intense drought that may have continued for several hundred years. This catastrophe is detailed in the Science articles “Development and Disintegration of Maya Political Systems in Response to Climate Change” by Douglas J. Kennett et al. and “Did Pulses of Climate Change Drive the Rise and Fall of the Maya?” by Heather Pringle.
Even as an intense effort continues to deemphasize fossil fuels lest the Earth become victim to heating that existentially threatens humans, fish, and other animals, oil companies continue to develop new sources of carbon-based energy. One such source is oil or tar sands, mainly extracted from the plains and prairies of the US and Canada, which produces some of the dirtiest fuels on the planet. The New York Times has reported on the adverse effects (environmental and economic) of tar sands and other extractive energy sources in the articles “The Tar Sands Disaster” by Thomas Homer-Dixon, “Coal Miners Struggle to Survive in an Industry Battered by Layoffs and Bankruptcy” by Clifford Krauss, and “The Real Cost of Coal” by David J. Hayes and James H. Stock. Other important sources on this are Seth Borenstein’s “Top Doctors’ Prescription for Feverish Planet: Cut Out Coal,” Michael Jakob and Jerome Hilaire’s “Climate Science: Unburnable Fossil-Fuel Reserves,” and Bob Johnson’s Carbon Nation.