Welcome to the anthropocene
‘We have been weeds and must learn to be gardeners.’ — David Grinspoon
Well, “welcome” might not be the best word to introduce the Anthropocene, the epoch of our making. For, indeed, the Anthropocene can be seen as a global package of bad news—for humanity as well as for our planet’s biosphere.
This subject is hotly debated, as is the very existence of this putative geological period dominated by thermo-industrial activities. However, that we live in a peculiar time of Earth’s history cannot be easily dismissed. The set of rapid and durable change induced by humans on the Earth System is conspicuous and ever more documented.
Officially though, the Anthropocene does not exist. Yet
It may be added permanently to the geologic time scale in coming years. It is the International Commission on Stratigraphy (see Working Group on the ‘Anthropocene’) that determines the denomination and the calibration of different divisions and subdivisions of geological time, which date back to the formation of the Earth, 4.6 billion years ago.
Unofficially however, the term is used widely in the scientific literature and, more recently, in publications dedicated to the general public.
So, might you ask, what is the Anthropocene?
First, the etymology. The Ancient Greek [anthropos] means "human being" while [kainos] means "new, current." The Anthropocene would thus be best defined as the new human-dominated period of the Earth's history.
The term was proposed in 2000 by Paul J. Crutzen, Nobel Prize in 1995 for his work on atmospheric chemistry and his research on stratospheric ozone depletion (the so-called "hole"), and by Eugene F. Stoermer in a publication (p. 17) of the former International Geosphere-Biosphere Programme (now part of Future Earth). But the concept itself, the idea that human activity affects the Earth to the point where it can cross a new age, is not new and dates back to the late nineteenth century. Different terms were proposed over the decades, such as Anthropozoic (Stoppani, 1873), Noosphere (de Chardin, 1922; Vernadsky, 1936), Eremozoic (Wilson, 1992), and Anthrocene (Revkin, 1992). It seems that the success of the term chosen by Crutzen and Stoermer is due to the luck of having been made at the appropriate time, when humankind became more than ever aware of the extent of its impact on global environment. It should be noted that Edward O. Wilson (who suggested Eremozoic, "the age of loneliness") popularized the terms "biodiversity" and "biophilia."
Technically, the Anthropocene is the most recent period of the Quaternary, succeding to the Holocene. The Quaternary is a period of the Earth's history characterized by numerous and cyclical glaciations, starting 2,588,000 years ago (2.588 Ma). The Quaternary is divided into three epochs: the Pleistocene, the Holocene, and now the Anthropocene.
The Pleistocene (2.588 Ma to 11.7 Ka) was a tumultuous era, during which more than eleven major glaciations occurred. Furthermore, the Pleistocene is also the time of early humans, the exit of our ancestors from Africa, the invention of the first tools, the evolution of bipedalism, the invention of graphic arts, cultural and linguistic refinements, and the dominance of Homo sapiens on the other hominids.
The Holocene (11.7 ka until now) is a time comparatively smoother in terms of climate variability. At the end of the last Ice Age, 12,000 years ago, a more stable climate regime settled on Earth. The ice gave way to temperate climates, and already, humans were present on all continents. It took a few thousand years for agriculture (domestication of land by humans for food mainly) to take off in the Fertile Crescent and elsewhere in Africa, China, New Guinea and South America. Thus went human progress, managing with success to feed ever more humans.
We are officially still in the Holocene. In fact, we are in the Phanerozoic Eon, Cenozoic era, Quaternary period and Holocene epoch. But now, the Earth's system does not seem to behave the same way as, say, at the time of Hesiod, Dante or Cervantes. The Earth of the 21st century is warming, urbanizing, being deforested and spoiled by novel entities. The comforting shell of the Holocene, which has fostered the birth of civilizations, is now punctured.
Read more about the Anthropocene on the page of the Anthropocene Working Group from the Subcommission on Quaternary Stratigraphy from the International Commission on Stratigraphy.
Here is the definition more or less impressionistic we propose for the Anthropocene:
"A period marked by a regime shift in the activity of thermo-industrial societies, its inflexion point following World War II, and which is causing global disruptions in the Earth System on a scale unprecedented in the Cenozoic: climate and ecological breakdown, environmental toxification, resources depredation, land cover denudation and radical transformation of the ecumene, among others. These changes command a major realignment of our consciousness and worldviews, and call for different ways to inhabit the Earth, aka Terra sapiens."
Go deeper: Anthropocene.info