2Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA), Universitat Autònoma de Barcelona, c/ Columnes s/n, 08193 Cerdanyola del Vallès, Barcelona, Spain. Email valenti.rull@icp.cat
Currently, an intense debate exists over whether the Anthropocene should be considered a formal series/epoch on the International Chronostratigraphic Chart/Geological Time Scale (ICC/GTS) or a geological event. Recent developments have cast doubt on the former option, with the rejection of a proposal submitted to the Subcommission of Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS) (Voosen, 2024; Witze, 2024). This rejection, which was further ratified by the International Union of Geological Sciences (IUGS, 2024), has strengthened the notion of the Anthropocene as a geological event, as proposed in recent years (Gibbard et al., 2022a, b). However, the term Anthropocene, originally coined to define an epoch (Crutzen & Stoermer, 2000), may be deemed unsuitable for naming an event. This commentary briefly reviews the most recent developments regarding the SQS rejection and suggests a more appropriate name for an alternative event.
The idea of an Anthropocene epoch emerged at the beginning of this century with the famous proposal by Crutzen & Stoermer (2000). They argued that human activities had introduced variability into the Earth System surpassing natural Holocene variability, thus necessitating the definition of a new geological epoch, which they called the ‘Anthropocene’. They proposed that this epoch could have commenced during the Industrial Revolution, with geological manifestations such as increased atmospheric greenhouse gases recorded in polar ice caps and biotic turnovers in recent lake sediments. Nevertheless, these authors did not dismiss the possibility that the Anthropocene might be older, potentially extending to encompass the entire Holocene period.
In 2009, the SQS established a task group, the Anthropocene Working Group (AWG), to evaluate the possibility of the Anthropocene as a new series/epoch following the Holocene. As is customary in defining new chronostratigraphic units, the primary task of the AWG was to identify a rock body overlying the Holocene, characterized by differential stratigraphic markers, and to assess the age of its base by geological methods. For a prospect to be considered a genuine chronostratigraphic unit, such as a series/epoch, it must represent a planetary-scale phenomenon evident in globally synchronous rock strata. With all this information, the proposal should be submitted for approval to the SQS and the ICS Executive, and then to the International Union of Geological Sciences (IUGS) for ratification.
After analyzing several possibilities – including the Late Pleistocene megafaunal extinction (50,000 yr BP), the Neolithic Revolution (8000-5000 yr BP), the Columbian exchange (1500 CE), and the Industrial Revolution (1760 CE) (Lewis & Maslin, 2015) (Fig. 1) – the AWG concluded that the only globally synchronous geological manifestation of human disruption began with the Great Acceleration (mid-20th century) (Head et al., 2022). This was marked by increases in radionuclides emitted by the first atomic bomb tests (1950s), as well as other stratigraphic markers such as fly ashes resulting from the combustion of fossil fuels, microplastics, pesticides, novel contaminants, and others. The AWG identified the first centimeters of sediments in Lake Crawford, Canada, as the type section for the Anthropocene Global Stratotype Section and Point (GSSP), or “golden spike”, along with other sediments and localities across all continents showing similar synchronous stratigraphic signals (McCarthy et al., 2023; Waters et al., 2023). The AWG proposal remains to be published but is available as a preprint (Waters et al., 2024).