THE ANTHROPOCENE IS PLASTIC

A critical reason to define an Anthropocene in the geologic timeframe is that humans have fundamentally impacted Earth and its processes. Arguments against it as an official division of geologic time involve International Union of Geological Sciences (IUGS) formal definitions requiring a specific chronostratigraphic type section or golden spike of inception. We propose pinpointing the ascendant human impact on the geologic record with plastics because people are unique producers of these unnatural petrochemical polymers that release potent greenhouse gases (GHGs) methane and ethylene throughout their lifecycle from their production through degradation. Plastics leave a distinctive, recognizable footprint in Earth’s geologic record, as well as our moon, Mars, asteroids and outer space, which is littered with debris from spacecraft launched since the mid-20th century. Plastics are ubiquitous ‘new forms of pollution’ found at all scales (micro- to macro-) in all Earth environments and biomes, and within organisms at all trophic levels. Plastics are now in sediments and documented as part of the rock cycle, forming new types of rocks that record a narrow timeframe of human activity. The “Plasticene” is a specific time in human technological innovation when plastics we developed became common in tools and our activities. Its onset can be precisely defined +/- 50 years. Archaeologists have long interpreted plastics in “historic trash” markers when interpreting chronostratigraphies. In practice, the Plastic Age is the most recent of Seven Ages of Materials identified by Smith and Vignieri (2021):

Stone Age: 2,500,000–3,200 BCE >> Bronze Age: 3,200–1,200 BCE

Iron Age: 1,200 BCE –100 CE >> Glass Age: 1300 CE–present

Steel / Aluminum Age: 1800s >> Plastic Age: 1900s–present

The Anthropocene is therefore NOT a relative term; in fact, the Anthropocene is plastic. The Plastic Age or Plasticene is already in full flex, whether or not it is an “official” IUGS designation; plastics identified and measured in soil and sediments are documented as indicators of human activity and impact. Petrochemical innovation, fossil fuel combustion and creation of plastics are directly intertwined with human agency, so the presence of plastics directly reflects us and our dominance on Earth (and beyond). Plastics in our geological rock record are human trace fossils attesting to our reliance on them.