, 2011, Steffen et al., 2011, Zalasiewicz et al., 2011a and Zalasiewicz

et al., 2011b). Rather Venetoclax chemical structure than constituting a formal chronostratatgraphic definition of the Anthropocene epoch, this consensus adopts, as a practical measure, a beginning date in the past 50–250 years: In this paper, we put forward the case for formally recognizing the Anthropocene as a new epoch in Earth history, arguing that the advent of the Industrial Revolution around 1800 provides a logical start date for the new epoch. (Steffen et al., 2011, p. 842) Steffen et al. (2011) follow the lead of Crutzen and Stoermer (2000) in identifying the rapid and substantial global increase in greenhouse gasses associated with the Industrial Revolution as marking the onset of the Anthropocene, while also documenting a wide range of other rapid increases in human activity since 1750, from the growth of McDonald’s restaurants to expanded

fertilizer use (Steffen et al., 2011, p. 851). In identifying massive and rapid evidence for human impact on the earth’s atmosphere as necessary for defining the Holocene–Anthropocene transition, and requiring such impact to be global in scale, Steffen et al. (2011) are guided by the formal criteria employed by the International Commission on Stratigraphy (ICS) in designating geological time TGF-beta inhibitor units. Such formal geologic criteria also play a central role the analysis of Zalasiewicz et al. (2011b) in their comprehensive consideration of potential and observed stratigraphic markers of the Anthropocene: “Thus, if the Anthropocene is to take it’s Adenosine triphosphate place alongside other temporal divisions of the Phanerozoic, it should be expressed in the rock record with unequivocal and characteristic stratigraphic signals.” (Zalasiewicz et al., 2011b, p.

1038). Ellis et al. (2011) also looks for rapid and massive change on a global scale of assessment in his consideration of human transformation of the terrestrial biosphere over the past 8000 years, and employs a standard of “intense novel anthropogenic changes …across at least 20 per cent of Earth’s ice-free land surface” as his criteria for “delimiting the threshold between the wild biosphere of the Holocene and the anthropogenic biosphere of the Anthropocene” (2011, p. 1027). A quite different, and we think worthwhile, approach to defining the onset of an Anthropocene epoch avoids focusing exclusively and narrowly on when human alteration of the earth systems reached “levels of equal consequence to that of past biospheric changes that have justified major divisions of geological time” (Ellis, 2011, p. 1027). We argue that the focus should be on cause rather than effect, on human behavior: “the driving force for the component global change” (Zalasiewicz et al., 2011a, p.