Anthropocene: The Human Age

Anthropocene is the term coined in 2000 by Paul Crutzen, the Nobel laureate from the Max Planck Institute for Chemistry, Mainz, Germany, to refer to the current geological epoch characterized by the global impact of human activity. The Anthropocene Working Group of the International Commission on Stratigraphy defines it as the present time interval, in which many geologically significant conditions and processes are profoundly altered by human activities (www.quaternary.stratigraphy.org). 

The conditions and processes include changes in: erosion and sediment transport associated with a variety of anthropogenic processes, including colonisation, agriculture, urbanisation and global warming; the chemical composition of the atmosphere, oceans and soils, with significant anthropogenic perturbations of the cycles of elements such as carbon, nitrogen, phosphorus and various metals; environmental conditions generated by these perturbations which include global warming, ocean acidification and spreading oceanic 'dead zones'; the biosphere both on land and in the sea, as a result of habitat loss, predation, species invasions and the physical and chemical changes noted above (www.quaternary.stratigraphy.org) 

According to a recent article in Nature Vol 519 (12 March 2015) by Richard Monastersky, momentum is building to establish a new geological epoch that recognizes humanity’s impact on the planet. But there is fierce debate among scientists whether or not to revise the Geologic Time Scale which is used by millions of people around the world, to accommodate the Anthropocene on top of the Holocene epoch (see scale below).

Source: www.serc.carleton.edu
One focus of the debate is the start of the new epoch. When did it actually began? Recent suggestions include 1610 and 1964. The 1610 suggestion is based on the dip in atmospheric carbon dioxide (measured from Antarctic ice cores) due to forest regeneration of huge areas of abandoned farmlands in Europe. The 1964 proposal is based on the high proportion of radioactive isotopes from the nuclear weapons testing (R. Gonzalez at www.io9com). But the Anthropocene Working Group considers the beginning of the 'Anthropocene' as c. 1800, around the beginning of the Industrial Revolution in Europe.

Once the proposal for an Anthropocene epoch is, after a long process, accepted by the International Union of Geological Sciences, the Quaternary period in the Geologic Time Scale above would consist of three (not anymore two) epochs: Pleistocene (2.6 mya to 12,000 yrs ago), Holocene (12,000 yrs ago to c. 1800) and Anthropocene (c. 1800 to present).

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