Here in paleoanthropologyland, we are often subject to the whims of the nomenclatura. These folks come up with new "logical" ways to name things, and we either have to adopt the new name or risk looking like outmoded dorks. That's more or less what has done in the term "hominid" -- if you're "with it", you call them "hominins" instead (of interest may be my 2005 review of the hominid-hominin problem).
I have approximately the same respect for this process as I do for the "Pluto is not a planet" crowd. I have no problem with the fact that some people know the system and use it effectively. But I think the scale out to be weighted against fads and in favor of conservativism in the names of things. After all, who is to say that we won't discover tomorrow a line of quadrupedal apes that are co-laterals to the australopithecines? If they're hominins, too, doesn't that mean we'll need another name for the australopithecine-human clade? There's no end to the literature changes we can initiate.
Well, that's not what has me riled up. On Nobel Intent, John Timmer writes:
Is the Anthropocene a new geological epoch?
These days, there seems to be a steady stream of species, from bats to bees, suffering from population collapses. In some cases, like fish, the cause is obvious; for others, like amphibians, the underlying cause (causes?) is less clear, but items such as environmental stresses and invasive species make for reasonable candidates. It's easy to wonder whether humanity's impact can really be so comprehensive, but there has been one sign that it is: geologists are seriously considering the possibility that we've triggered a new geologic epoch, which some are calling the Anthropocene.
I've seen the term appearing in a number of papers recently, and decided to look into it. It appears the term was only coined about six years ago, but it's gained serious credibility within scientific circles. Perhaps the most detailed treatment of the topic was published earlier this year in a member's journal of the Geological Society of America.
Silly me. I thought we already had a name for this: the Holocene. That's the geological epoch that began 10,000 years ago, with the recession of the last Ice Age. It was during the early Holocene that some human groups became agriculturalists and started exerting large-scale changes on local and regional environments. Domestication of animals and the consequent displacement of wild herbivores was a Holocene phenomena. Human-caused burning of dry woodland-grassland habitats was essentially Holocene (although in some areas it began earlier). The transformation of tropical forests by swidden (slash-and-burn) agriculture: Holocene.
All these things did not begin at once, they stretched over 10,000 years. But the most important thing is that they didn't start at once. They started over the course of the last 10,000 years. There's no reason to call this time period a new name like "Anthropocene." Holocene covers it nicely.
Timmer points to a paper from earlier this year describing the concept of "Anthropocene" and supporting evidence. The logic, from a geological standpoint, is that human activity may have altered sedimentation (by damming major rivers and accelerating erosion) and faunal and floral communities in a way that would be recognizable in a stratigraphic sequence. In other words, recent human activity may generate a stratigraphic boundary as distinctive as the K-T or Permian-Triassic boundaries.
The paper concludes:
Sufficient evidence has emerged of stratigraphically significant change (both elapsed and imminent) for recognition of the Anthropocene—currently a vivid yet informal metaphor of global environmental change—as a new geological epoch to be considered for formalization by international discussion. The base of the Anthropocene may be defined by a GSSP in sediments or ice cores or simply by a numerical date.
This is my problem: Since when did we make scientific decisions based on "vivid yet informal metaphors"? Sure, there are many scenarios for what may result from human action, including what has already happened, that put it on the scale of past geological changes. But this should be an empirical decision, not a speculation. In that respect, even the Pluto decision was better than this idea, because it was rooted in an empirical observation -- many hundreds or thousands of objects might ultimately be identified as planets, which raises the practical problem of naming and delimiting them. There was the obvious choice of referring to "the traditional nine planets," or instead of redefining "planet".
Here, we have a possible empirical consequence of current activity -- maybe someday the differences in sedimentation at the Industrial Revolution will be important enough stratigraphic divisions to merit global rather than merely local recognition. And a small group of geologists, specialists in defining boundaries of time periods, are pushing the idea.
I think that if these folks are going to define geological periods based on the impact of human behavior, that they really should consult with anthropologists and archaeologists. My own opinion is that the Industrial Revolution is merely an amplification of processes begun much earlier, and that its most important geological effects (like damming) are local. There is an argument that the faunal and floral exchanges (and to a lesser extent, extinctions) are globally recognizable, but it seems doubtful to me that these can be meaningfully limited to a period shorter than the Holocene, since widespread animal exchanges are as early as dogs and dingos.
In the end, the rest of us working in fields where the time periods are important will live with whatever consequences. And schoolkids learning the geological history will read about how the Industrial Revolution is formally recognized as an event on the scale of the K-T extinction. I am concerned that the main impetus behind the name "Anthropocene" is as a subtle means of gaining political traction. In that sense, it leaves me with the same feeling as "hominin" -- which in the end has been yet another way to beat the dead horse of human "uniqueness".