Proposals to give the latter part of the present geological period (the Holocene) a new name … the Anthropocene … are misguided, scientifically invalid, and obnoxious. However, there is a use for a term that is closely related to “Anthropocene” and I propose that we adopt that term instead.
The pithy title of the paper making this proposal is “Are we now living in the Anthropocene” (sic: no question mark is included in this title, enigmatically).
It is not an entirely stupid idea. The paper argues that there are major changes of the type often used to distinguish between major geological time spans that are unique to the present day, so maybe there is an argument for a named period. The paper more specifically argues that these features are largely anthropogenic.
A case can be made for its consideration [of the Anthropocene] as a formal epoch in that, since the start of the Industrial Revolution, Earth has endured changes sufficient to leave a global stratigraphic signature distinct from that of the Holocene or of previous Pleistocene interglacial phases, encompassing novel biotic, sedimentary, and geochemical change. These changes, although likely only in their initial phases, are sufficiently distinct and robustly established for suggestions of a Holocene-Anthropocene boundary in the recent historical past to be geologically reasonable.
Why is this scientifically invalid? There are several reasons. The Anthropocene is minimally as scientifically valid as the Holocene, the bit of geological time that would be trimmed to make room for the Anthropocene. and the Holocene is not scientifically valid. The Holocene is a non-glacial period distinct from the previous Pleistocene because the Pleistocene is a glacial period. Or at least, that is more or less (I’m oversimplifying a bit) how things were conceived when these periods were defined. It turns out, however, that the Holocene is almost certainly just another interglacial during a longer epoch of periodically repeating and increasingly severe glacials.
This means that we are not in the Holocene, but rather, in the Pleistocene. Therefore, the proposal to call the present (and going back a short period of time) something different would rest on he argument that the defining factors of the Anthropocene are more determinative of geological epochal identity than the defining factors of the Pleistocene. And they are not. Glacial cycles are big powerful things that change every aspect of the biota, carve up huge areas of the earth, deposit enormous loads of sediment globally that would not otherwise (in the absence of glacial action) be deposited, change sea levels dramatically, and so on. The geological and biotic markings of the present century and the last … all the mucking around that humans are doing … is not demonstrably greater than, or even nearly equivalent to, the great changes wrought by glaciation.
Then, there is the scale problem. Geological periods are defined by changes that can not only be viewed from a great distance in time, but can’t be missed from so far away. It should be as reasonable to define a geological epoch as it is to note the existence of a mountain chain from many kilometers away. It might be that anthropogenic changes to the biota and the landscape are sufficiently blatant and long lasting to create a such a distinct distance, or they may not. The Holocene itself is invalid because it is too near-sighted (in time) of a concept, considering a mere several thousand years and calling it a distinct period. And we (well, they, I wan’t even born yet) got that totally wrong. How does a few centuries of observation translate into a valid geological periodization? It does not. It is possible that we can define a new period that begins about now (plus or minus in geological time). But those proposing the Anthropocene are several million years premature. They need to be more patient.
Finally, while anthropogenic effects cannot be used to define a new geological period, they have already, in my view, met or exceeded the minimal requirements to be considered a geological “event.” In particular, an extinction event, and in addition, a major biogeographical event. Never before has there been such a massive transfer of species … in all the Kingdoms of life … across otherwise separated continents. This massive, multi directional invasion, as well as the widespread harvesting of the plant life of certain major biomes (such as forests), have caused a mass extinction. Some of the prior mass extinction events have been much more severe than the present one, but perhaps not all. There is evidence that the present mass extinction event is only getting started. But unlike geological periodizaiton, which requires the perspective of millions of years to really evaluate, the reality and validity of a mass extinction event can be observed and verified in much less time.
Mass extinction by invasion and steady habitat loss, as opposed to mass extinction by massive volcanic eruption or extraterrestrial object impacts, will be very slow as mass extinction events go, but the relevant comparison here is between days or months on one hand to centuries on the other. We see that more vulnerable, or more targeted, biomes are well into the range of the highest levels of extinction rates. In Polynesia, about 90% of endemic bird species have gone extinct (varying greatly across the region) in the last 400 years. Birds are going extinct at an alarmingly high rate globally. I believe that there are entire biomes that have been wiped out long enough ago that the numerical contribution of these losses to the overall event are uncountable (this includes European temperate forests and seasonally dry African tropical forest).
I don’t think it is reasonable to define a new era called the Anthropocene. But I do think it is entirely scientifically valid to define an event that could be called the Anthropogenic Extinction.
I started out saying that the proposal of the Anthropocene is both scientifically invalid but also obnoxious. Well, it could be obnoxious simply because it is scientifically invalid. But there are other reasons. The main reason is that it is anthropocentric. “But wait,” you say, “It might not be a valid period, but the stuff the authors of that paper are talking about are human-caused, so why not call it ‘anthro-whatever whatever.'” But that, dear reader, would be yet another anthropocentric misconception.
To the extent that the events of the modern era, including over harvesting major biomes and global warming, are cause by human activities, it also has to be recognized, from a strictly evolutionary and biological point of view (as opposed to a human-centric point of view) that this is not a human event, but a multi-species event. Viewed from the perspective of a sentient being from another planet that has absolutely no human-like preconceptions and no way to directly relate to the point of view of any Earthling species … say a sentient being evolved from silica dust particles that that exist as dust-sized individuals organized in eusocial metabeings that are several Jupiters in size and that do not perceive light … humans are certainly not the only thing, or even the most common thing, in this picture. The authors of this paper argue, for instance, that human population size has skyrocketed in the last several thousands of years. But how? Why? Our little/big silica-beings would view this very differently. They would see the emergence, some 10,000 years ago, of fewer than a half dozen different forms of grass as dominant species, spreading across the planet at the expense of many other life forms. The spread of these grasses (rice, corn, wheat, etc.) is associated with, possibly facilitated by (but wait, these silica beings might not be adaptationists, so we should not put ideas in their dusty little brains) four and two legged, mobile warm-blooded things that tend the grasses, and in return, are fed by the grasses.
This may sound funny, but I’m not joking. Not even a little. Modern human societies do not exist outside of biology, and some of the most important aspects of our energetics as a species derive from very tight knit co evolutionary relationships with a variety of grasses, microbes, and a few other plants, and some animals. All this talk about recent, and possibly accelerated, human evolution all about this co-evolutionary relationship.
But I suppose I would not expect geologists to be keyed into that way of thinking.
But, obviously, while we may agree that there is an extinction event going on now, the same reasoning that tells us to avoid the anthropocentric terminology should caution us to not call this event the “anthropogenic extinction event.” So we need another name.
Most of the plants involved in this extinction event are either grasses or other Monocots (such as plantains). So this could be the Monocot Event. But since the rise of grasslands per se is actually a Miocene event, perhaps this could be the Monocot-Anthropoid Event. Clearly, more work is needed on coming up with a suitable term. Suggestions are welcome!
Zalasiewicz, J., Williams, M., Smith, A., Barry, T.L., Coe, A.L., Bown, P.R., Brenchley, P., Cantrill, D., Gale, A., Gibbard, P., Gregory, F.J., Hounslow, M.W., Kerr, A.C., Pearson, P., Knox, R., Powell, J., Waters, C., Marshall, J., Oates, M., Rawson, P., Stone, P. (2008). Are we now living in the Anthropocene. GSA Today, 18(2), 4. DOI: 10.1130/GSAT01802A.1
Pimm, S. (2006). From the Cover: Human impacts on the rates of recent, present, and future bird extinctions. Proceedings of the National Academy of Sciences, 103(29), 10941-10946. DOI: 10.1073/pnas.0604181103
This paper is also being discussed here: