To understand earthquakes in Oklahoma, the Earth’s sixth mass extinction, or the rapid melting of the Greenland Ice Sheet, we need the Anthropocene—an epoch that acknowledges humans as a global, geologic force. The Holocene, a cozier geologic epoch that began 11,700 years ago with climatic warming (giving us conditions that, among other things, led to farming), doesn’t cut it anymore. The Holocene is outdated because it cannot explain the recent changes to the planet: the now 400 parts per million of carbon dioxide in the atmosphere from burning fossil fuels, the radioactive elements present in the Earth’s strata from detonating nuclear weapons, or that one in five species in large ecosystems is considered invasive. Humans caused nearly all of the 907 earthquakes in Oklahoma in 2015 as a result of the extraction process for oil and gas, part of which involves injecting saltwater, a byproduct, into rock layers. The Anthropocene is defined by a combination of large-scale human impacts and gives us a concept that provides us with a sense of both our power as well as responsibility.
In 2016, the Anthropocene Working Group, made of 35 individuals, mostly scientists, voted that the Anthropocene should be formalized. This means a proposal should be taken to the overlords of geologic epochs, the International Commission on Stratigraphy, which will decide on whether to formally adopt the Anthropocene into the official geological time scale.
Any epoch needs a starting point, and the Anthropocene Working Group favors a mid-20th century start date, which corresponds to the advent of nuclear technology and a global reach of industrialization, but it won’t be that simple. Two geologists, one of whom is the Chair of the International Commission on Stratigraphy, pointed out that units of geologic time are not defined only by their start date, but also by their content. They argue that the Anthropocene is more a prediction about what could appear in the future rather than what is currently here because, in geologic terms, it is “difficult to distinguish the upper few centimeters of sediment from the underlying Holocene.” At the same time that hardcore geologists are pushing back against formalizing the Anthropocene, a recent article in Nature argued that social scientists should be involved helping determine the start-date of the Anthropocene. Social scientists’ involvement in delineating the geologic time scale would be unprecedented, but then again, so is this new human-led era.
Whether the geologic experts anoint it as an official epoch, enough of society has already decided the Anthropocene is here. Humans are a planetary force. Not since cyanobacteria has a single taxonomic group been so in charge. Humans have proven we are capable of seismic influence, of depleting the ozone layer, of changing the biology of every continent, but not, at least so far, that we are capable of living on any other planet. The more interesting questions may not be about whether the Anthropocene exists or when it began, but about whether we are prepared for this kind of control.