#24-2. The Plasticene Epoch is Upon Us
In which the E@L proposes naming the current geological epoch for microplastics
Does anybody really know what time it is? Or what era? It’s all quite plastic. Geologists like to organize time into categories according to strata in the earth’s crust. These categories vary from millions of years (Eons and Eras) to thousands of years (Periods and Epochs). Most of the current divisions are defined by changes in fossils, i.e. the remnants of living creatures, or major extinction events. The kind that might be caused by a massive meteor smashing into the earth.
In the big scheme of time, we are currently residing in the Holocene Epoch (last 12,000 years) of the Quarternary Period (last 2.6 Million years) of the Cenozoic Era (last 65.5 Million years) of the Phanerozoic Eon (last 542 Million years).
Geological Time
During this most recent epoch, humans have made indelible alterations to the ecosystems and climate of Planet Earth. The obvious signs of this include large-scale agriculture, high-density cities, fossil-fuel pollution, and climate change. We’ll probably leave fossils too, as have the Neanderthals and Australopithecines before us. These changes have induced some people to propose that we might now be living in a new Epoch, that should be called the “Anthropocene”.
But without specific fossils, how would that boundary be defined? Whatever signal that is eventually agreed on, it must be defined using evidence found within geologic strata. And, it must have more-or-less simultaneous impact on the whole planet.
Some think that the new Epoch started in the 19th century during the Industrial Revolution, with the widespread use of coal and oil for energy production. Others, however, think that it started in the 1950s, when human-induced changes in Earth’s climate started to become apparent. One usable marker is radiocarbon from atomic bomb testing in the 1950s, which is present in soils, trees, and even deep-sea corals.
The organization responsible for defining earth’s time scales is the International Union of Geological Sciences (IUGS). In 2016, that body agreed that it was time for a new geological unit, and that it should probably start around 1950. The defining characteristics could include radiocarbon layers, soot from burning fossil fuels, plastic pollution, and even chicken bones (not for Voodoo spells, but because of their industrialized production since then).
After examining evidence from many different locations, the definitive location for defining the Anthropocene Epoch was selected in 2023. Crawford Lake is a small pond, or sinkhole, near Toronto, Canada. The pond is narrow (about 100 m) but deep (24 m), so that surface and bottom waters do not mix. Thus, materials that settle to the bottom are not disturbed, and are eventually buried by sediments from the surface layers. In addition, the unique pH of the surface waters causes mineral crystals to form that settle to the bottom and create distinct layers in the sediment. These are so clear that individual years can be identified. The lake bottom has been studied by dropping a sampling device containing liquid nitrogen, which causes sediments to freeze to it without disrupting their vertical stratification.
The most distinctive markers in the lake bottom are plutonium from bomb testing in the 1950s, which forms a distinct spike in the sediments. Other evidence includes fly-ash from fossil-fuel power plants, and nitrites from fertilizer application. In addition, changes in types of pollen indicate changes in local plant species resulting from climate warming.
The decision about the timing of the Anthropocene, and its defining location, will be made at a meeting of the IUGS in 2024. Some scientists, though, are skeptical. Humans have been altering the ecosystem and climate for many years prior to 1950, so perhaps a fuzzier boundary definition is needed. Plutonium will eventually degrade and may not remain in sediments forever. Alternatively, geologic time periods have all been defined thousands or millions of years after they occurred. Humans have only been on earth for a blip, so maybe it’s too soon to decide what our impact has been. Who’s to say what the effect of our brief presence will be in another thousand years or so?
The Plasticene Proposal
In response to all this academic argumentation, I would like to propose an alternative classification for our current situation. Although some might say having no credentials in geology is a barrier, I believe it allows me a more critical view. As Ecologist at Large, my remit also includes Advocate of Alternative Energy, Foe of Fossil Fuels, and Proponent of Plastic Prohibition.
My suggested name for our current position in the space-time continuum is the Plasticene Epoch. Plastic is the perfect marker for geologic time periods. Since 1950, over 8 Billion metric tons of plastic have been produced, and over 6 Billion tons have been discarded into earth’s environment. Less than 10% has been recycled, and over 10 million tons enter the ocean every year. Over 500 Billion plastic bottles are produced every year, and the majority of them are discarded. Plastic items, including bottles and bags, break down into microplastics, microfibers, and nano-plastics that have been found in every environment on earth, and inside most organisms. Microplastics comprise the majority of the Great Pacific Garbage Patch, covering an area the size of Alaska in the Pacific Ocean.
The ubiquity and harmfulness of microplastics are well known. And they don’t degrade like plutonium, so they may be around even longer. In addition to plastic particles, we have also contaminated most of our foods and environments with plasticizers, called phthalates (of which BPA is one). These compounds mimic natural hormones such as estrogen and can have detrimental effects on the reproductive ability of aquatic organisms as well as humans.
(The Ecologist@Large has just completed a detailed study of plastic production and discards, and the impact of micro- and nano-plastics, in a companion article called “The Great Plastics Experiment”, which will become available to paid subscribers in late January.)
Fortunately, we are finally awakening to the perils of plastics and starting to develop alternatives. Compostable polymers have been touted as “biodegradable” but only under specific circumstances in industrial composters, and not in landfills. Instead, they break down into smaller pieces, contaminate other recyclables, and end up creating more pollution. Scientists (Them again!) are now conducting research on biodegradable plastics that include enzymes to help the plastic self-destruct into natural organic compounds that can be further consumed by biological organisms.
This is good news for Proponents of the Plasticene. If we can make the switch to really biodegradable plastics in the near future (say, by 2050?) then the environmental signal of non-biodegradable plastic will be confined to a period of about 100 years. That should be a fuzzy enough boundary, and is likely to be identifiable for millennia to come, both of which should be satisfactory criteria for the Anthropocene Antagonists.
So, Dear Readers, mark my words. You heard it first from the Ecologist at Large. The Plasticene Epoch is upon us. I will stoicly await acclamation from the academic community.
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https://geologyscience.com/geology-branches/paleontology/geologic-time-scale/
Better link to the time scale
You've made an excellent and entertaining case, though it feels like a better case for identifying the likely future signature than for naming the epoch. Even if we can't know what, a million years hence, the sedimentary/fossil record will look like, it seems a fair bet that human activity will have marked it. Hence the Anthropocene. I'm not crazy about the word - awkward and hinting at hubris - despite having built my writing around it. But it still seems the most appropriate, even if only as an editorial attempt to wake us up to the fate we're making. I like the sound and sense of Plasticene, as I like Stephen Pyne's Pyrocene (https://www.stephenpyne.com/disc.htm), but they seem only to capture a facet of the larger transformation.