As we approach the end of the year, we may not only be saying goodbye to 2023, but also the geochronologic unit of time we have been living in to date. In 2024, scientists will be making a decision on whether we have entered the Anthropocene, a new epoch marked by human impact on the planet.
Broadly speaking, the Anthropocene (derived from the Greek words anthropo, meaning “man” and cene for “new”) represents a time of planetary change that has come as a direct result of human activities, such as burning fossil fuels and increased deforestation. The idea was first made popular in 2000, by the late meteorologist Paul Crutzen.
At present, the scientific community is unsure whether the Anthropocene has officially started and whether it is any different from the Holocene – the current epoch – which started around 11,700 years ago. The crucial question that needs to be addressed is whether human activity has changed the Earth’s system to such an extent that it is reflected in the rock strata.
In July 2023, a group of scientists responsible for defining this potentially new epoch – the Anthropocene Working Group (AWG) – turned to Crawford Lake, Canada, as the case study for making their decision. They chose this spot because plutonium isotopes from nuclear weapons tests can be found at the bottom of the lake, which, they believe, dates the start of the Anthropocene to the early 1950s.
The fact that the news about Crawford Lake has already been revealed is somewhat unusual. Typically, information like this would only be released after the International Union of Geological Science (IUGS) has ratified it. But this departure from the norm is crucial, so the AWG believes, as the implications are significant to everyone. However, this is far from uncontroversial.
Here and now or emerging?
The work of the AWG has drawn criticism since the news broke earlier this year. The objections, however, are not focused on whether human activity has had a significant impact on the planet – the evidence for that is overwhelming – but when the Anthropocene started.
There are some scientists, such as Erle Ellis, a former AWG member at the University of Maryland who resigned after Crawford Lake was selected, who object to how the Anthropocene has been defined by the working group.
For Ellis, restricting the Anthropocene to an epoch diminishes the impact humans had on the planet before the mid-20th Century. There is plenty of evidence to show our species was leaving its mark long before that time, such as in the Industrial Revolution, when carbon dioxide levels in the atmosphere began to increase.
Rather than seeing this as the advent of a new epoch, individuals like Ellis argue that the Anthropocene should be regarded as an ongoing event.
In its defense, the AWG argues that, from the mid-20th century, the sheer level of human impact on the planet cannot be ignored, and that “big changes” occurred at this time with the advent of the atomic age.
The next step in the decision-making process involves the AWG’s proposal, which was submitted in October 2023, being accepted by the Subcommission on Quaternary Stratigraphy (SQS), its parent body. If it is accepted, the proposal must pass two further rounds of voting by the International Commission on Stratigraphy and the International Union of Geological Sciences.
If the proposal passes these tests then, by August 2024, we will officially be living in a new epoch brought about by our collective activities.