The scientists who have the final say on our accepted notions of geological time have decided we are not living in a new epoch called the Anthropocene – but it is still a useful concept.
International Union of Geological Sciences' top officials said after a series of internal votes that it has rejected the notion of a new epoch defined by far-reaching human impacts on the planet since the 1950s.
Despite opposing a new formal unit of the Geologic Time Scale, IUGS said on Thursday the Anthropocene "will nevertheless continue to be used not only by Earth and environmental scientists, but also by social scientists, politicians and economists, as well as by the public at large. It will remain an invaluable descriptor of human impact on the Earth system."
A working group within IUGS, which had been working on the proposal for 15 years, recommended declaring a new epoch in part based on the spread of radioactive isotopes from hydrogen bomb tests.
It had pointed to sediment from the bottom of a lake in Ontario, Canada, that contained artificial radionuclides from weapons testing – or what it called markers of human-caused planetary change.
'A span of less than a single human lifetime'
The Anthropocene concept has become fairly well-established both in popular culture and scientific literature, which the IUGS acknowledged.
But it pointed to concerns about naming a new epoch that would be only decades old in contrast to declared epochs lasting several million years.
"While there can be little doubt that the term Anthropocene is now well established in the public domain, and will no doubt continue to be used in popular and scientific discourse, it has not been without its critics," the organization said.
Here are its main points:
- "Some have pointed to the fact that anthropogenic effects on the Earth’s environmental and climate systems long predate the mid-20th century (e.g. early agriculture; the industrial revolution in western Europe, the colonization of the Americas and Pacific, etc) and hence the Anthropocene has much deeper roots in geological time.
- "Others have expressed unease about a new unit in the GTS that truncates the Holocene but with a span of less than a single human lifetime, it sits uncomfortably within the GTS where the units span thousands or even millions of years.
- "A third cause for concern is that the human effects on global systems are time-transgressive and are also spatially and temporally variable, so that their onset cannot be adequately represented by an isochronous horizon as reflecting a single point in time."
