We are in the Holocene Epoch... or are we? Some believe we have already entered a new era- one characterized by Humanity. Are we now in the Anthropocene Epoch? It has yet to be formally accepted by the International Commission on Stratigraphy, or the International Union of Geological Sciences as part of the Geological Time Scale, but it's pretty clear that humans have already altered the face of the planet in a way that can be traced back directly to... humans. So should we credit ourselves our own Epoch?
The biggest aspect of this debate isn't whether or not humans have changed the planet, but when we should say our reign of terror began. Some leading figures believe that we should mark the beginning of the Epoch at up to 15,000 years ago, when our over-hunting helped drive the extinction of the mega fauna. Others believe that it began 8,000 years ago when we started to domesticate animals and till the land. The industrial revolution is the beginning of the Epoch for some, and I would have to agree. The epoch should be defined as "The point when an individual human event began influencing the planet on more than a regional scale." It was not when human artifacts were discovered or when cities began to form.
During the Industrial Revolution we begin to expel CO2 and other greenhouse gasses into the atmosphere. The ever increasing economies of scale brought factories into the world. Distinct pollutants begin to creep into the Ice cores as CO2 levels rise, forever marking our place on this world. The latest date we should consider marking the beginning of our epoch is 1945, because of the introduction of radioactive isotopes into the atmosphere and Ice core.
Using a thought experiment, I will show you not only why I believe the Anthropocene should be an Epoch, but why it began with the Industrial revolution.
Imagine yourself as an alien Xenoarchaeologist. Your job is to find out whether or not this star system has, or can support intelligent life. You approach the 3rd planet from a relatively small yellow dwarf. It has a tidally locked moon, and from a distance the planet appears to be covered in blue and green. A brief scan of the moon finds dozens of space ship crash sites and a few successful landings. Strange script is scrawled across the ships, along with flags that must have been of some symbolic importance. You move on from the moon to find hundreds of satellites in orbit, most nonfunctioning, but some still sending out weak signals. This planet must have contained intelligent life long ago.
You turn your scanners to the planet and find exactly what you expected. Old mining sites, places where huge amounts of earth had been removed and transported. None of the machinery used to do it remains, but the scars left upon the planet are unmistakable. Large, unnatural, rectangular, cavernous, complexes pocket mountainsides. Holes and craters missing from the surface, many of them now lakes. Mountains that have been terraced, and countless hills that have been sliced in two for... Pathways? Zooming in you find trace amounts of oxide deposits, rubber, plastic, concrete dust, and asphalt chunks. All following fairly straight lines to huge oxide deposits. Scanning for similar trends you find the surface of the planet covered with an intricate network of ground pathways, leading to what must have once been cities. All that remains are dense patches of oxides, strange concentrations of rare elements, cut gemstones, and tons of plastic.
The ice core data shows a dramatic increase in CO2, as well as a sudden and abrupt addition of radioactive isotopes. The same radioactive isotopes that were found within a handful of cave systems, as well as buried in seemingly random places. They were possibly a way to contain the waste.
A brief scan of the local ecosystem presents the hypothesis that monoculture was their established agricultural method. The assumed ancestors of several domesticated species exist on all continents with very little fossil record, or evidence of migratory patterns. Many of these animals may contain sequences of implanted DNA. Further research is required but this may be evidence of genetic engineering.
You turn your scan to detect plastic, and the entire planet glows on the screen. Scoffing, you mutter under your breath "Damn, another extinct and wasteful species."
To answer the question we have to ask our archaeologists; "what would someone else discover?" The answer is radiation and plastic. There wouldn't be any argument over at what point we began our turn. The Anthropocene Epoch began between 1800 and 1945. Any relics before that could be determined Pre-Anthropocene. It doesn't mean human relics are any less important, meaningful, or human. It just means we couldn't change the climate with a stone axe.