THE 'ANTHROPOCENE' EPOCH: ITS CONSIDERATION BY ICS SHOULD BE A DISCUSSION AND NOT A DEBATE

Human impact on the Earth system has long been recognized, but it has received greatly increasing attention in the media since the 'Anthropocene' was proposed as a new epoch in the Geologic Time Scale. That the 'Anthropocene' should be ratified as a unit of the International Chronostratigraphic Chart/Geological Time Scale deserves serious consideration by the International Commission on Stratigraphy (ICS). However, it must be examined critically with regard to the ICS guidelines for establishing a single, hierarchal set of global chronostratigraphic units at the ranks of Stage, Series, and System. GSSPs, approved by ICS and ratified by the International Union of Geological Sciences, define the boundaries of the chronostratigraphic units that are the basis of the Geologic Time Scale. Accordingly, the drive to establish the 'Anthropocene' is focused on the criteria on which to define its beginning. However, this is a mistaken concept because the chronostratigraphic units are based on stratigraphic content, and the GSSPs merely set the limits, both upper and lower boundaries, of the chronostratigraphic units. This then raises the question of the stratigraphic content of the 'Anthropocene'. Another fundamental point to consider is that any stratigraphic record that might be attributed to the 'Anthropocene' would not be used for reconstructing Earth history in the 'Anthropocene' for the simple reason that events of the 'Anthropocene' are directly observed by humans and are expressed in terms of human calendars and chronometers. In this sense, studies of the 'Anthropocene' are not stratigraphic. On the other hand, a cascade of human induced events is now underway just as cascading events have led into other major perturbations of the Earth system. Thus, ICS should consider expanding the concepts on which it bases the units of the Geologic Time Scale. Furthermore, ICS should actively encourage input from the greater geoscience community during its consideration of the 'Anthropocene'. The question of the 'Anthropocene' as a ratified unit of the ICS International Chronostratigraphic Chart/Geologic Time Scale should not be a matter of debate, but instead a discussion in which all points of view are presented and in which all points of view are given respectful consideration.