On January 8th, scientists released a comprehensive report showing that human impact on the planet—including the atmosphere, the oceans, everything that lives and breathes and many things that don’t—has pushed the world into an entirely new geological epoch: the Anthropocene. Later this year, geoscientists will meet in an attempt to formally approve the official starting point of this new era. Potential dates range from 6,000 years ago when humans really began to lay down roots and spread agriculture and deforestation across the planet during the “early Anthropocene” to the peak of the so-called “bomb spike” of artificial radionuclides in 1964.
Geologic eras, which are measured in tens of thousands, if not tens of millions, of years, represent major changes that can’t simply be undone by the next administration, or even the next civilization. Dinosaurs went extinct 65 million years ago at the end of the Cretaceous period and they aren’t coming back.
The Holocene, the most recent geological era, began began about 12,000 years ago with the rise of humans at the end of the last ice age. The Anthropocene surmises that not only have humans now risen to dominance, but they are physically impacting the world in a way that will alter it for many thousands of years. How are they doing this? Primarily by creating lots of stuff.
The Human Scene and all of its Trappings
According the report by the Anthropocene Working Group, published in Science magazine, human activity over the last several thousand years has led to the “rapid global dissemination of novel materials including elemental aluminum, concrete, and plastics.” These materials form “technofossils” that take extremely long periods to decompose. As Bloomberg reports, “Humans have invented more new kinds of minerals—pottery, glass, bricks, and copper alloys, to name a few—than the earth has seen since oxygen-producing bacteria evolved 2.4 billion years ago.”
The report’s abstract states that since at least the mid-20th century, when the first thermonuclear weapons were launched, humans have been altering the planet’s “long-term global geologic processes at an increasing rate.” Many scientists consider this post-WWII nuclear era to be a good starting point for the Anthropocene as it will leave a clear timestamp in the geologic record.
Another recent study looking into a specific start date for the Anthropocene determined that the spread of agriculture across North America some 6,000 years ago marking the very early stages of the era could provide an appropriate starting point. Published in the journal Nature by scientists at the Smithsonian’s National Museum of Natural History, the study found that the spread of human civilization since then has likely caused “barriers to dispersal for plant and animal species” resulting in landscapes becoming “more island-like” and fragmented, according to S. Kathleen Lyons, a paleobiologist at the Smithsonian's National Museum of Natural History and leader of the research.
Whether the official start of the Anthropocene is determined to be 50 or 5,000 years ago, Lyons and her peers acknowledge that early human impact pales in comparison to what humans are achieving in the 21st century.
“I think that modern human-driven forces, like climate change and pollution, are orders of magnitude more destructive than what early humans were doing,” she said. “But more and more, research into the Holocene and the Pleistocene is showing that when humans started migrating around the globe, they started having major, unprecedented impacts.”
The Destructive Impacts are Really Adding Up
More than half the concrete ever produced was created within the last two decades, and enough concrete has been made to cover every square meter of the world in a kilogram of the artificial construction material. There are at least five giant gyres of plastic waste circulating in the world’s oceans, with some 300 million metric tons of plastic produced annually—or enough to equal the weight of the more than seven billion people on Earth.
Species of flora and fauna are so stressed by human activities that many scientists believe the planet has already entered its sixth mass extinction. According to the report in Science, more than 75% of species of animals and plants could be gone within a few centuries. Prior mass extinctions, having occurred tens and hundreds of millions of years ago, mark the transition points of past geologic epochs. While these were driven by cataclysmic events such as asteroid strikes, volcanic eruptions, and continental drift, the current extinction crisis is a man-made undertaking.
Furthermore, many electronics and other modern-day necessities are composed of elements mined from the earth. Increasing demand for rare earth elements and other minerals has made it so that mining now moves three times more sediment every year than all the world's rivers.
Dams also disturb natural sediment flow, thus slowing the growth of many river deltas at the same time that the added mass is needed to offset the sea level rise being driven by climate change. A new paper in Science by a group of ecologists warns that plans to dam the world’s three greatest and most biodiverse tropical rivers—the Mekong, Amazon and Congo—could have “far-reaching effects on biodiversity” and possibly lead to the loss of up to one third of the world’s freshwater.
To most people unaffiliated with the field of geosciences, the exact start date of the Anthropocene is not what matters, but the environmental, economic and societal implications of the changes likely to occur within it. These are its defining legacies writ onto a human scale, and they are already with us in many ways.
The turmoil in the Middle East has been exacerbated by drought, likely driven at least in part by climate change. The global quest for fossil fuel extraction is really just a race to exhaust resources from another geologic era; coal and oil that took tens of millions of years to form, and less than a few hundred years to deplete. Food security and agricultural productivity—a key aspect of maintaining relative peace in a world predicted to reach a population as high as 11 billion by 2050—depends on successfully managing soil cycles, and heavy fertilizer use over the past century has doubled the amount of nitrogen and phosphorus in soil.
Air pollution, a crippling and critical issue across the world in 2015, especially in fast-developing Asia, has actually been going on for thousands of years. Roman courts considered civil claims over smoke pollution 2,000 years ago. Looking for soot in the geologic strata is one way of demarcating the Anthropocene. The main difference is that now air pollution has gone from a local issue to a global one as greenhouse gas emissions give rise to climate change.
The Anthropocene is a period like no other in Earth’s nearly five billion year history, and it is just getting underway. Will naming this new epoch make any noticeable difference when it comes to human impact on the planet? Only time will tell.