The Anthropocene is a new geological epoch dominated by human impacts on our planet.
The activities of humanity over the past few decades are significant enough to mark a new epoch, replacing the Holocene. This proposal remains controversial regarding its definition and precise delineation.
2024 may mark humanity’s entry into a new epoch. (Image: Trust my Science).
The term Anthropocene was proposed by Dutch meteorologist Paul Crutzen in 2000 to explain the impacts on climate and biodiversity due to the accumulation of greenhouse gases as well as the damage from the overconsumption of natural resources by humans.
These disruptions will surpass the changes that have occurred during the Holocene in which we currently live, which began approximately 11,700 years ago.
It is important to note that the Anthropocene does not include the initial impacts from human activities; it is defined more broadly, and scientists refer to this as “the Great Acceleration.”
The Great Acceleration is a period that began in the mid-20th century, marked by significant and rapid geological changes around the world, the effects of which far exceed those caused by natural phenomena (except for the impact of the asteroid that wiped out the dinosaurs).
The Anthropocene Working Group (AWG) has identified a set of relevant indicators (in geological strata) coinciding with this period.
These include radioactive isotopes from the initial nuclear tests, carbon particulates from the burning of fossil fuels, microplastics, changes in biodiversity leading to the extinction of certain species, and overpopulation.
These indicators have been recorded at several significant geological sites around the world. Last July, Crawford Lake in Canada was selected by the AWG as a benchmark for studying Anthropocene indicators.
According to the research group, the evidence will be sufficient to officially consider whether we are entering a new geological epoch.
Rapid Increase in Plutonium Levels
The reference location established by the AWG is identified through the description of materials and time, referred to as “Global Stratotype Section and Point” (GSSP) or “Golden Spike.”
This method has been widely used to establish units or geological epochs over the past 540 million years.
Identifying a Golden Spike requires the local presence of a physical marker, which must be visible to the naked eye, and at least one related indicator, such as specific geochemical changes.
For the Anthropocene, scientists have chosen the presence of plutonium as the physical marker.
Crawford Lake was chosen as the site to study indicators related to the Anthropocene. (Image: Trust my Science).
The sediment layers taken from Crawford Lake (proposed as a reference point for the GSSP) are about 15cm thick. The calcite layer forming their foundation dates back to the summer of 1950, indicating a rapid increase in plutonium levels.
This signal is accompanied by an increase in carbon particulates, a decline in pollen, and the extinction of certain animal species, all of which indicate significant disruptions in global ecosystems.
A Proposal Under Debate
The announcement from the AWG has sparked debates. The delineation of new geological epochs is typically only published after the scientific community within the International Union of Geological Sciences (IUGS) has analyzed and voted on it.
On the other hand, some experts disagree with defining the Anthropocene as a geological epoch, as well as with its proposed start in the 1950s.
To resolve these debates, it has been suggested to consider it more like a geological event.
However, media announcements before the official voting by scientists could facilitate the acceptance of the Anthropocene as a new geological epoch.
The AWG members believe that this decision should be regarded as an open process because of its significance to the public.
The AWG submitted this proposal in October 2022 to the Subcommission on Quaternary Stratigraphy (SQS). If confirmed, it will undergo two more rounds of voting before the Anthropocene is officially recognized as a geological epoch, possibly by next year.
