The concept of the Anthropocene epoch was born in February 2000 out of a moment of spontaneity. Chemist and Nobel Prize winner Paul Crutzen had been listening to a narrative emerging at an international convening of scientists in Mexico.

All day, scientists had presented data that showed how the human-caused changes in climate, chemical cycles and biology of recent decades were jarringly different from the relative stability of the Holocene, the geological epoch that began 11,700 years prior. They kept referring to the remarkably rapid environmental changes of the late Holocene.

Exasperated, Crutzen finally broke into the discussion: “We aren’t in the Holocene anymore, we’re in … the Anthropocene!” The improvised term quickly caught fire as a foundational concept among earth scientists, and in the last decade the word has proliferated through other sciences, the arts, humanities and popular culture.

Along the way, “Anthropocene” gained many meanings and implications unrelated to—or even opposing—Crutzen’s original concept, blurring and sometimes wholly obscuring its original meaning. But what did Crutzen intend by the Anthropocene, a concept since enhanced and refined by years of scientific study?

It’s absurdly simple. The shift from the Holocene to the Anthropocene epoch hits like a brick wall when looking at graphs that show changes in three major greenhouse gases and in global temperature during the last 30 millennia. All four of these critical planetary parameters shift from near-horizontal to near-vertical lines in the last 70 years or so. The graphs are simple, but they show changes in atmospheric chemistry and—lagging a little behind—temperature, that affect the habitability of the planet for all its organisms, including humans. On a time scale of millennia, the shifts don’t resemble a hockey stick as much as a stair step. Furthermore, these changes affect the whole atmosphere and ocean, so they are essentially irreversible on any human time scale. Our distant descendants will still be living with the planetary changes that humans have wrought in a single lifetime.

Greenhouse Gases Graphic
The stunning effect of humans on the atmosphere can be seen in the concentration of three important greenhouse gases: nitrous oxide, methane and carbon dioxide. These gases have increased far more in the last 70 years than in the previous 30,000 years or more. Global temperature has begun to spike as a result, and it will continue to rise as the full effect of higher greenhouse gas concentration is felt. Martin Head

If we zoom in on the time axis to look at just the last 300 years, ten human generations, we see remarkably large and rapid change in a whole range of factors that mark the effect of humans at a global scale: not just carbon emissions, but also production of metals, plastics, fertilizers, concrete and farm animals, and even a giant increase in the ultimate geological currency: sediment. The amount of sediment moved every year by humans now exceeds the amount moved by non-human processes by a factor of 15.

Cropping the time frame tightly in this way, we see that the global shifts are most rapid beginning in the mid-20th century. The Anthropocene Working Group, a body of 34 scientists from 14 countries constituted in 2009 by the International Commission on Stratigraphy, proposed placing the beginning of a new Anthropocene Epoch in 1952, when sediments are marked globally by the first major increase in the element plutonium, derived from the earliest tests of thermonuclear weapons.

Anthropocene Graphic
Scientists proposed recognizing a new geological epoch, the Anthropocene, marked by rapid changes beginning in the mid-20th century. Sediments deposited in the last 70 years are marked by abundant artificial materials including concrete, metals, plastics and fertilizer. Ecosystems have also been transformed by the great increases in fertilizer production (ammonia) and raising livestock (meat production). Humans are also prodigious producers of sediment. Colin Waters

By proposing a formal, geologically defined Anthropocene epoch, the working group intended to provide a precise definition for this recent, large, permanent and rapid transition in Earth’s physical, chemical and biological systems.

The proposal was rejected by the international hierarchy of stratigraphy—of which the International Commission on Stratigraphy is a part—without citing substantive reasons, but most public criticisms of the Anthropocene stem from a range of sources: from within the heart of geology, to well outside it, among the social sciences and humanities.

Hoover Dam
Tourists look down at the Hoover Dam. The amount of sediment settled behind the world’s thousands of big dams would cover all of California to a depth of five meters. Robert Nickelsberg / Getty Images

Across a spectrum of disciplines, the Anthropocene touched—and often jabbed—a nerve: sometimes as a gut response to a disturbing new idea and sometimes with discomfort at unfamiliar sociopolitical implications. For whatever reasons, the Anthropocene came under fire.

But the barrage of criticism has often focused on what the Anthropocene isn’t rather than what it is. Fundamental misconceptions have come to surround this concept and to cloud its meaning. Here we debunk ten common myths about the Anthropocene.

1. The Anthropocene fails to represent all human impacts.

This is true enough—but it misses the point entirely. Recognizing an Anthropocene epoch does not at all underplay the impacts that humans have caused for many millennia by hunting, by farming, and by building cities and trade networks. But those early impacts were not global, were not synchronous around the planet and did not shift the global environment permanently. The reason for naming a new geological epoch, both in Crutzen’s original formulation and in the highly detailed proposal of the working group, is to mark the departure of the Earth and its inhabitants from the stable planetary system of the Holocene. The Anthropocene epoch was never meant to encompass all anthropogenic impacts.

2. The Anthropocene is too short to be a geological epoch—just one human lifetime.

The Anthropocene’s duration is short, true—so far. But it’s the Holocene that shows the greatest change in duration from other epochs: nearly three orders of magnitude (0.0117 million years versus 2.57 million years for the Pleistocene epoch that precedes it). The difference in duration between Holocene and Anthropocene epochs is proportionately less, and the Anthropocene represents far more significant and enduring change to the planet than does the Holocene.

3. The Anthropocene is just a blip in Earth history.

Or, as the New York Times writes, a senior member of the geological time-scale hierarchy calls it “a blip of a blip of a blip.” What this point of view misunderstands is that these approximately 70 years have altered the planet fundamentally and set it on a new trajectory. Already, many geological signals are sharper than, and as pronounced as, the sudden carbon release and global warming that initiated the Eocene epoch 56 million years ago.

Take just the climate impacts from burning fossil fuels, of which 90 percent have been burned in the last 70 years. These impacts will roll across the planet for at least many thousands of years. We and many generations to come are locked into a climate unlike that of the Holocene. Carbon dioxide already in the atmosphere will make the Earth hotter than it has been for at least 3 million years. Many of the biological changes of the last 70 years are permanent, too: extinctions, of course, but also the spread of many species through the intended and unintended assistance of humans, making fauna and flora more homogeneous worldwide. The biosphere has been changed forever. This is no blip.

4. Anthropocene strata are “minimal” or “negligible.”

That’s a very geological objection—but it’s wrong. Humans have, since the mid-20th century, been prodigious reshapers of the landscape and movers of rock and sediment (now, by more than an order of magnitude than natural sediment movers such as glaciers and rivers.) The amount of sediment settled behind the world’s thousands of big dams would cover all of California to a depth of five meters, and such sediments are full of distinctive markers, like pesticide residues, metals, microplastics and the fossils of invasive species. To define a time period formally, geologists must identify distinctive signals in sediments or rocks that can be correlated around the globe, and the presence of such markers is ubiquitous. The geology is real.

Plastic Pollution in California
Plastic debris collects after a rainstorm near Culver City, California. Microplastics that result from such debris can often be found in sediment. Citizen of the Planet / UIG via Getty Images

5. The geological record is too complex and gradational to draw one single boundary for the Anthropocene.

All of history (of Earth and of humans) is complex, is gradational and varies through time and across space. Nevertheless, geologists define epochs because such time units are useful, indeed indispensable to their work. In geology, each time unit is precisely defined by a “golden spike”—a specified level in a sedimentary succession at a specified location that is chosen because it can be correlated to other sedimentary sequences around the globe. This golden spike identifies a global time plane, but the planetary transition that motivates the placement of a golden spike can be anything but simple.

The last ice age of the Pleistocene gave way to Holocene interglacial conditions over the course of about 13,000 years—and took a different course between Northern and Southern Hemispheres. Yet the defined Holocene boundary within that transition, at 11,700 years ago, is accepted and used without complaint. The Holocene-Anthropocene transition is much sharper and more globally synchronous, and so is easier to define and recognize.

6. Other animals have affected the environment and caused geological change, so there’s nothing special about the Anthropocene.

Other animals have indeed changed the environment, but that can help rather than hinder the recognition of geological time intervals. For instance, the rise of mobile, muscular animals that could burrow through sediment serves as the basis for defining the Cambrian Period. But none of those previous changes has swept across all environments on the planet so quickly—or been triggered by an animal conscious of the changes it was making. This consciousness, we note, is yet to be effectively translated into action to ward off the worst consequences of these changes. Too many still pursue economic and industrial development without considering the long-term cost to planetary health.

7. The Anthropocene blames all humans equally for the global environmental crises.

The Anthropocene assigns neither blame nor credit; it simply recognizes a great, abrupt and more or less permanent change to the course of Earth history. There is no doubt that some humans, societies, institutions and nation-states have driven far more change than others, and that the benefits and costs of change have been and are unevenly distributed. The societal value of the Anthropocene epoch is that it announces the unambiguous scientific evidence showing that humans have permanently changed the global environment. And it might encourage us to recognize that we all must deal with the rapid, permanent, global changes that are underway.

8. The Anthropocene signals defeat in our efforts to mitigate environmental change.

The first step in solving problems is to diagnose them. We cannot return the Earth to the conditions in which our grandparents or any other Holocene generation lived. But we can make wiser decisions about the future that will ameliorate and mitigate change. That’s realism, not defeatism.

9. Naming the Anthropocene after humans is hubristic.

The planetary transformation that ushered in the Anthropocene epoch was caused by humans. It could have been called a lot of things, but Anthropocene caught the imagination of many because its meaning is evident and accurate.

10. The Anthropocene is just a publicity stunt.

If only that were true. Accepting that we are no longer living in a Holocene world is a first step in addressing the issues facing humans and non-humans in the immediate future.

These myths have persisted in the scientific community despite being systematically refuted in scientific papers by the Anthropocene Working Group and others. This suggests that, like all myths, they are reactions based on ideology, conviction or personal philosophy rather than evidence. These misconceptions lie at the heart, too, of the recent formal rejection of the Anthropocene epoch by the hierarchy of international stratigraphy.

Why has the Anthropocene been misunderstood and mythologized in so many ways? Probably because it’s deeply uncomfortable to many. It’s very brief (so far). It includes smelly landfill sites as strata to “foul up” a geological time scale that is sacrosanct to many geologists. And it raises the specter that the calm abstractions of geological time have come up against the tough predicaments we face in the present and future.

Change is hard, and the Anthropocene is an uncomfortable concept. It is hard to accept that we as a society have gained so much power to change the Earth and have thought so little about how to use that power. Scientific knowledge can transform our perspectives (think of heliocentrism and evolution)—so it’s not surprising that the Anthropocene is hard to accept. But, recognizing our role in suddenly, recently driving the Earth towards a new future is a necessary first step to engaging with the planetary changes we have set in train.

Get the latest on what's happening At the Smithsonian in your inbox.