Anthropocene

The notion that humankind has changed the world is not new. However, with terms such as anthropozoic, psychozoic, and noosphere proposed over the last century, the idea of humans as a new global forcing agent can be considered recent and closely linked with the proposition and dissemination of the term anthropocene. It was coined more than a decade ago by Paul Crutzen, one of the three chemists who shared the 1995 Nobel Prize for discovering the effects of ozone-depleting compounds.

The term anthropocene first appeared in the paper titled “The Anthropocene,” published in the International Geosphere–Biosphere Programme Newsletter in May 2000, where Crutzen and his colleague Eugene Stoermer—a professor at the University of Michigan—noted that many forms of human activity are now capable of undermining the natural environment. For instance, in the case in carbon and nitrogen cycles, the amount that is fixed synthetically competes with the amount that is fixed by the planet’s vegetation, land, and oceans.

In their paper, Crutzen and Stoermer argued for the appropriateness of the term anthropocene to characterize the current geological epoch, emphasizing the human footprints on the planet that have been seen in geology and ecology over the last decades. Two years later, in 2002, Crutzen restated the argument in a concise article titled “Geology of Mankind” in the prestigious journal Nature. According to him, the anthropocene could have begun in the latter part of the 18th century, based on analyses of air trapped in polar ice that showed the beginning of increasing concentrations of carbon dioxide (CO2) and methane at the global level.

After these two groundbreaking articles, the term gained popularity and began to appear more often in the scientific literature of a range of disciplines and topics, leading to a more profound and careful consideration of the term. Many consider that the term is not only vivid—as much for the public as for scientists—but that it was also coined at a time of growing realization that human activity was changing the Earth on an unprecedented scale, with changes that are now seen as permanent, even on a geological time-scale. These attributes influenced scientists to increasingly use the term anthropocene to denote the current interval of time, one dominated by human activity. However, many argue that the term remains informal and is not precisely defined.