The term 'Holocene' - roughly translating to "recent whole" - refers to the geological era in which we currently reside. The Holocene began approximately 12,000 years ago, which means that by geological standards it is so young it's practically still a fetus. Despite this, the Holocene has seen geological transformation at an incredible pace, and a new force of change has prompted some to argue that we have entered a new era. While geological change is natural and constant - volcanoes erupt, tectonic plates shift, the chemical breakdown of the atmosphere fluctuates - something is different about the pace of and scale of geological change in recent centuries. As Paul J. Crutzen and Eugene F. Stoermer pointed out in a 2000 article in the IGBP Newsletter, human activity has fundamentally altered the Earth's systems to such a degree that homo sapiens can now be considered a geological force. Thus they proposed the term 'Anthropocene' to characterize the fact that humans now play a leading role in shaping the planet.
But how useful is this term? From a geopolitical perspective, I think it's helpful. As Simon Dalby argues, the term and its constitutive academic outcome - Earth System Science - "requires us to rethink assumptions of our living within an external environment" (2007: 103). Forget the age-old dichotomy between 'man' and 'nature'; the "Anthropocene" tells us that man is nature. No, this is not a new idea... but the term is food for thought for the planet's future prospects. It raises the question of how we humans will continue to shape the Earth's experience - after all, unlike volcanoes and shifting tectonic plates, we (theoretically) have consciousness to guide our awareness of our own actions. And so the term has its place, particularly if it is used as a tool to get people to realize the role we can play in protecting the environment.
And yet I am compelled to speak on behalf of the phytoplankton: After all, humans are not the only species that behave as a geological force, let alone the only species that fundamentally alters the atmosphere. As it turns out, phytoplankton are responsible for the production of over half of the world's oxygen! Not only that, they seem to be an essential component of ocean ecosystems. In a recent study by Daniel Boyce published in Nature (2010), phytoplankton are said to be "the fuel on which [marine ecosystems] run". Further still, phytoplankton play an essential role in seeding clouds across the planet (by producing dimethyl sulphide, which then reacts with seawater to form sulphur particles in the atmosphere around which water droplets form). In short, phytoplankton are a geological force without which much of the life on Earth would not be capable of survival - and there may just be other geological forces out there of which we are less keenly aware. And yet, the seeming absurdity of referring to a geological age as the "phytoplanktocene" makes me question whether the other term - the Anthropocene - really carries any (geological) weight? Theoretically, we've always lived in the phytoplanktocene - the era began when single celled organisms started photosynthesizing and converting carbon dioxide into oxygen. I'm not a geologist, but I can see why some geologists are skeptical about the extent of the human impact. Perhaps their big picture perspective reveals how in the long run, humans are just another species that has - like all species - simply altered their environment.
On the other hand... the interaction between humans and phytoplankton gives us reason to appreciate the term "Anthropocene" in a new light. As the Boyce study mentioned above has reported with some measure of despair, the global population of phytoplankton appears to be shrinking by 1% each year! In fact, since 1950 the Northern Hemisphere has lost 40% of its phytoplankton. Needless to say, the loss of phytoplankton would be catastrophic for many of the planet's living inhabitants. And the cause? Boyce explains, in a somewhat ironic twist, that it is anthropogenic climate change itself that is causing ocean currents to change (as a result of warmer temperatures), which in turn is not circulating adequate amounts of nutrients to the areas of the ocean where phytoplankton reside. In short, human activity appears to be reducing the relative power of phytoplankton to serve as a geological force which in turn makes life on Earth possible! If we're not careful, the "Anthropocene" may come to take on a new meaning: the epoch when human beings lived!