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).