The collective bastion of anthropocentrism has pooled its brain power into a tiny puddle of an idea - and not a particularly good idea. In fact, a perfectly foul idea. This is it: We will commemorate humanity, in all our self-loathed glory, by establishing an official Geologic Epoch of the human endeavor -
I've already had occasion to comment on the validity of even the Holocene Epoch in an earlier post here in The Terrane. But this..,.,.
For those who don't know about such esoterica, there is an international commission within the geologic community which is charged with establishing official stratigraphic designations, including the naming and demarcation of the various subdivisions of geologic time, beginning with the longest chunks of time - the aeons - and working down successively through the eras, periods, epochs, ages, stages, all segmented into ever-thinner little slices of past time.
Well, a number of years ago we who live and work in the here and now were slotted into a new little quantum packet of time: a nano-sliver known as The Holocene - translated as the "entirely recent" epoch. The miniscule little tick and tock of the Holocene encompasses the most recent 11,500 years of Earth history (as of the year 2000). Without too much cross-stepping into my earlier post, the beginning of the Holocene marks the ending of the Pleistocene (meaning "most recent"), which is also known as the epoch of the Ice Ages, of which there were four. The end of the Pleistocene also corresponds with the end of what paleoanthropologists refer to as the Paleolithic Age - the beginning of civilization.
So - are the conditions of the Holocene different than they were in the Pleistocene? What we have now are continental glaciers which have retreated to cover only Greenland and Antarctica and alpine glaciers on our highest peaks and ranges. As I have posted before, I am dubious of the need for the assignation of an "entirely recent" age (Holocene), when it is no different, geologically, from the "most recent" age (Pleistocene).
But now, at an asylum near you, enter this new spot of arcane nomenclatural chicanery - the Anthropocene in which we will have continental glaciers STILL on Greenland and Antarctica and alpine glaciers on our highest peaks and ranges. (Note: For those who want to argue that the continental glaciers are melting and that the Himalaya will be ice free in 35 years I will simple say: "Do try to keep up!").
So why is this even an issue you might ask, with more than a little justification? Because some resume-building poltroons think that we humans have made a mark so indelible on the Earth's epidermis that it will have a lasting geologic signature. The would-be Anthropocene is a self aggrandizing proposal to elevate humanity to the scale of a geologic agent. You know the kind of stuff I mean: continental erosion by running water and glaciers, the stick-slip movement of entire land masses along faults, mountain building (aka orogenies) the movement of continents around the globe.
Let's air this out so we can all think about it fairly. Has the creation of our modern civilization resulted in a geologically indelible difference to the Earth?
The first thing to consider are the bases for the demarcations of time which have been applied for all the previous geologic time intervals. All previous designations of time slots of the Epoch level and above were based on:
- the presence of geologic formations deposited or emplaced on such a large scale that the need for a global correlation warrants a unique time-stratigraphic designation;
- the evolutionary inception and/or extinction of a taxonomically significant group (e.g., the Devonian Period is the time of the very first amphibians - not a single toad species, but all amphibians). The evolution of a new genera is not even significant enough. New epochs are defined on complete ecological shifts, which are caused by complete geological shifts.
For example, the distinction between the Pliocene and Pleistocene is based on the inception of a series of four glacial epochs punctuated by interglacial stages which lasted for more than two million years.
The continental glaciers during those times not only eroded the picturesque alpine montane views we all love, but they also deposited all the eroded sediment from those vast sculptural episodes in huge geologic deposits which are unique, readily identifiable and traceable on a global scale; e.g., the entire coastal plain of the eastern U.S. from Massachusetts to Texas, inland as far as St Louis and extending well over a hundred kilometers under the Atlantic Ocean, is veneered with Pleistocene glacial outwash derived from the millions of years of glacial bulldozing followed by rinsing the sedimentary residues out of the mountains during each of the interglacials. THAT, is a geologic event of global proportion - and that is just the eastern U.S.
As far as I can discern, we are not causing the deposition of new geologic formations. Nor is increased erosion as a result of poor agricultural practices resulting in the deposition of sediments of a unique enough character that they could be distinguished by future geologists. So we are not really the root cause of the deposition of geologically unique, or even distinct, formations. The Anthropocene fails on count 1.
What about new species. Well - about 50% of the Anthros who inhabit the would-be Anthropocene will almost kill you if you so much as suggest that evolution occurs at all - even on the species level. But a whole new taxonomic group? OK. Let's ignore that fringe (can 50% be considered a fringe group?).
There have been new species within the time proposed as the Anthropocene. The newly identified, recently evolved Spanish Sparrow for instance, or the LLanos A strain of the Orinocan Fruit Fly of the Drosophila paulistorum complex, among others.
But not a whole new order, which is usually required for a new time designation. Consider, for example, the change in fauna from the Oligocene to the Miocene. HUGE changes across marine taxa. In particular, we find petroleum by exploring and tracking the fossilized evolutionary changes from Oligocene to Miocene plantonic foraminferra - the ecological/evolutionary shift was THAT pronounced across the entire class of organisms that it is a recognizable marker horizon.
So, nothing new recently on the faunal succession front. What about extinction??? Ahhhhhh!!!!! Haven't we been exhorted incessantly that we are causing a mass extinction of truly geologic proportion? That will qualify won't it?
Well, the key in other instances when the end of one period (or era) is marked by a mass extinction is that the ensuing period is distinguished from the former by the inception of new lineages on a taxonomically significant scale. It is not enough to say that a "mass" extinction should qualify to designate a new period. We also have to have the ability to look back to see if there was indeed a succession into a new ecological norm. So, for example, the end-Permian extinction was followed by new adaptive radiations and the commencement of entire new taxa - or at least a shift in the global distribution of life. The average geologic duration of any species is about four million years - most epochs are longer than that, so there are MANY extinctions within the time boundaries of virtually all epochs.
Another examples would be the demise of the dinosaurs at the end of the Mesozoic Era after which mammals became the ecologically dominant taxa in the Cenozoic Era. That is significant even though mammals had been around for a long time already. But that was the extinction of an entire Sub-Order with many hundreds of Super-Families, Families, Genera and species - all related - and all disappearing at around the same time and opening new niches for other taxa to occupy and radiate; http://www.palaeos.org/Dinosauria_taxonomy
The magnitude of the geological shift is related to the magnitude of the ecological response (that's what I mean by the heading of this entire blog). The larger the change, the greater the ecological shift and greater ecological shifts have warranted more significant sub-divisions of the geologic time scale. So, the evolution of land insects, or the first reptiles were events significant enough to be awarded a new geologic period. The complete loss of dinosaurian lineages, along with about 70% of other taxa and the replacement with new taxa heralded the change from one Era to another. Changes in continental positions which resulted in changes in global circulation which led to adaptations of existing taxa into new forms to adapt to changed, but somewhat similar conditions, warrant a new epoch.
The important point is that it has only been possible to recognize and identify a different geologic time by a change from one set of dominant conditions to another set. The loss of even 1,000 species does not mark the end of a geologic age and the beginning of another unless by losing those 1,000 species the entire balance of the global ecology is upset to the point that there is a new and recognizable ecosystem based on the successor populations.
The extinctions we see now are nowhere near so extensive or so concentrated into single taxonomic groups and certainly not global. In fact, what we see is the loss of a relatively few species in disparte groups. Of those, most of the macro-species live exclusively on a single island or within an isolated archipeligo. The astounding numbers of species which are touted as being proof that we are causing a mass extinction are estimates based on some questionable extrapolation.
In some trees in tropical rain forests there are entire communities of beetles which, in some instances, are unique to an individual tree. It is estimated that there are some large trees in which up to a thousand unique species of beetles live - and do not live anywhere else. And each of those beetle species can have a unique suite of species-specific parasites, which makes for many species which could become extinct if that tree were to be cut down for logging purposes. Cut down 100 trees and the possible number of species which might have lost their habitat and become extinct is potentially large.
Somewhere in this spectrum of loss, from a few island species to thousands of beetles and germs, lies the number of species which we are told we are causing to become extinct.
So, in terms of changes in evolution/extinction, we are not causing the loss of a cosmopolitan community of fauna on a global scale, and we are not seeing human-induced spurts in new taxa. The Anthropocene fails on Count 2.
So, what IS the basis of this proposal which has spawned entire symposia and cost millions of dollars? Some make the claim that the land use changes which we cause via urbanization will be visible in the rock record. In other words, if a future geologist goes exploring and discovers a concrete roadway buried beneath 8 meters of sediment, then she will be able to state definitively that that horizon is positively identifiable as Anthropocene and deposits below and above can be dated as before and after, respectively.
Although the above logic is true on a general concept, it is not true that the materials of our civilization will last through geologic ages. Just look at those concrete bridge rails which date from the WPA in the 1930s
They are crumbling and decomposing back into the sand, limestone and aggregate from which they were derived. A mere 80 years. Asphalt degrades and ultimately will be consumed by soil bacteria. Steel and iron rust to scale and are leached away in no time. Geologic time is soooo mind-mangelingly vast that our materials don't stand a chance.
Look, the Pleistocene is the briefest epoch of the Neogene Period (click pic for a larger view), which is the briefest period of the Cenozoic Era, which is the briefest era of the Phanerozoic Aeon, which is the briefest of the aeons. The scant 2,500,000 years of the Pleistocene would be enough time to render almost invisible that scourge of materials of our devising, radioactive nuclear power plant waste. With a radioactive half life of 50,000 years, during the short time of the Pleistocene, ONE MILLION kilograms of radioactive waste would be reduced to a mass of 0.0000008 gram. (I know that is a simplification and there is more to this little exercise than that particular reaction, but the point is still valid).
Someone who is a specialist in the future might be able to discern the subtle geochemical clues to identify iron concentration residues as being "Anthropocene" but it's a real stretcher to designate a time period on the assumption that you know what future conditions will be like. Even if such a future specialist could identify the signature, the problem is that, within the limits of already-designated epochs there are literally thousands of similar markers which positively and uniquely identify when in time a geologist is looking when inspecting a formation. Those unique conditions are used to designate ages or stages which are smaller subdivisions within the scheme - not entire epochs.
This silly exercise in academic abstraction reminds me of the ongoing wars over the term "Renaissance".
That epithet is now considered invalid by many post-modern scholars for the simple reason that it was coined by the people who were alive at the time. It is looked on as arrogant and self-aggrandizing., Many modern scholars prefer the term "early modern period" to Renaissance to distinguish the difference between Medieval times and now.
A group of modern geologists is attempting to elevate our own time interval to a geologically significant status. What I find really offensive is that by selecting the name they have, they denigrate all previous generations of our lineage. What they are proposing is that anyone who lived before about 1800 is excluded from the "epoch of the human". Everything in our past has aggregated over time to result in what we are and what we are doing now. If one wants to designate a geologic time which is based on human endeavor and impact to the planet, it should begin with civilization -about 10,000 to 12,000 years ago. Oh... wait a minute. That's already been done. It's the