The Anthropocene within the Geological Time Scale: a response to fundamental questions

The Anthropocene as a prospective new, ongoing series/ epoch must be defensible against all relevant concerns. We address the seven, still-relevant challenges posed to the Anthropocene Working Group by the Chair, International Commission on Stratigraphy (ICS), in 2014. (1) Concept or reality? The Anthropocene possesses a substantial, sharply distinctive stratigraphic record recognisable through many proxy signals from the mid-20th century onwards; (2) GSSP or GSSA? The Anthropocene can be defined by a GSSP and correlated globally; (3) Past or future? The Anthropocene unquestionably represents geological time, its transformations having already moved the Earth System beyond Holocene norms towards an irreversible future trajectory; (4) Utility? The Anthropocene's distinctive material content allows useful delineation on geological sections/ maps; (5) Indelibility? Many of the Anthropocene's transformative effects cannot be subsequently effaced or overprinted; (6) Fit within the Geological Time Scale (GTS)? The Anthropocene represents a unique, youngest, interval in Earth history and strata of profound significance; (7) What is its value? The chronostratigraphic Anthropocene has conceptual usefulness even informally, but would then lack the clarity, stability and recognition that formalization provides. Without its formalization, the GTS would no longer accurately reflect Earth history, diminishing the relevance of geological science for analysis of ongoing planetary change.