UK, May 26, 2011 (The Economist): In 2000 Paul Crutzen, an eminent atmospheric chemist, realized he no longer believed he was living in the Holocene. He was living in some other age, one shaped primarily by people. From their trawlers scraping the floors of the seas to their dams impounding sediment by the gigaton, from their stripping of forests to their irrigation of farms, from their mile-deep mines to their melting of glaciers, humans were bringing about an age of planetary change. With a colleague, Eugene Stoermer, Dr Crutzen suggested this age be called the Anthropocene–“the recent age of man”.
The term has slowly picked up steam, both within the sciences (the International Commission on Stratigraphy, ultimate adjudicator of the geological time scale, is taking a formal interest) and beyond.
The most common way of distinguishing periods of geological time is by means of the fossils they contain. On this basis picking out the Anthropocene in the rocks of days to come will be pretty easy. Cities will make particularly distinctive fossils. A city on a fast-sinking river delta (and fast-sinking deltas, undermined by the pumping of groundwater and starved of sediment by dams upstream, are common Anthropocene environments) could spend millions of years buried and still, when eventually uncovered, reveal through its crushed structures and weird mixtures of materials that it is unlike anything else in the geological record.
The fossils of living creatures will be distinctive, too. Geologists define periods through assemblages of fossil life reliably found together. One of the characteristic markers of the Anthropocene will be the widespread remains of organisms that humans use, or that have adapted to life in a human-dominated world. According to studies by Erle Ellis, an ecologist at the University of Maryland, Baltimore County, the vast majority of ecosystems on the planet now reflect the presence of people. There are, for instance, more trees on farms than in wild forests.
All these things would show future geologists that humans had been present. But though they might be diagnostic of the time in which humans lived, they would not necessarily show that those humans shaped their time in the way that people pushing the idea of the Anthropocene want to argue. The strong claim of those announcing the recent dawning of the age of man is that humans are not just spreading over the planet, but are changing the way it works.