The case for the Anthropocene

A single species, humans, has gained the capacity to greatly change the entire biosphere—the areas where living things are. In the history of life on Earth, no other species has reached this point.

Geologists have worked out a system of naming large sections of Earth’s time. Thousands of years are called “epochs.” Tens of millions of years are “periods.” Hundreds of millions of years are “eras.” The longest measurements of time are called “eons.” Geologists call our current epoch the Holocene. It started about 10,000 years ago. At this time, temperatures became stable after the last ice age. The word Holocene comes from Greek roots: holo meaning “whole” and cene meaning “new.” Hence, Holocene means “wholly new.”

In 2000, the chemist Paul Crutzen suggested that we are in a new epoch. He called it the Anthropocene. He proposed that human domination has changed the planet greatly. It has, therefore, brought on a new epoch. The name Anthropocene has not been officially adopted, but many geologists have begun using it.¹

But why should we care about this name change? This means that it’s the first time scientists have seen one species, humans, having an effect that has greatly changed the planet. Unfortunately, these changes have been almost entirely negative.

Evidence of change

What kind of evidence could show that humans have begun to dominate and alter the life systems of Earth? The clearest and most familiar is climate change.² Around the world, temperatures on average have risen about 1 degree Celsius. Several serious effects are now occurring. Plants and animals are moving northward. Glaciers are melting. Storms and droughts are getting more severe. Weather patterns are changing and global temperatures are rising. Behind these weather patterns are changes in the Earth’s atmosphere that scientists can track over geologic time.

A tiny part of Earth’s atmosphere is made up of “greenhouse gases.” These gases hold in heat reflected from Earth. They do not let heat escape into space. One of these greenhouse gases is carbon dioxide (CO2). During the past million years, CO2 ranged from 180 parts per million (ppm) to 280 ppm. This range was due to processes not affected by humans. Since the beginning of human agriculture, the atmospheric concentration of CO2 has risen from 280 ppm to the current (2017) level of 405 ppm.³ This rise happened much faster than ever before. It was mostly due to humans burning fossil fuels in the last 250 years.

To keep our climate from warming, leading scientists urge us to reduce the concentration of CO2 to 350 ppm. CO2 lingers in the atmosphere for thousands of years. Because of this, we still have CO2 in the air from the 1900s. It continues to contribute to warming. If we are to stop that effect, scientists tell us that global emissions (release) of CO2 must be cut by 50 percent by 2030. It must fall to net zero by the year 2050. However, from 2014-2016 worldwide emissions increased by 1.6 percent. The increase for 2018 was 2.7 percent. Emissions in China rose by about 5 percent and India rose by more than 6 percent. It reflected the rate at which these countries’ emissions continue to grow as their industry grows. The United States’ emission increased by 2.5 percent. However, emissions in the European Union decreased by almost 1 percent. The 24th annual U.N. climate conference took place in 2018. United Nations Secretary-General António Guterres issued a grim warning. He stated, “We are in deep trouble with climate change… Even as we witness devastating climate impacts causing havoc across the world, we are still not doing enough, nor moving fast enough” (Washington Post). Guterres said irreversible and disastrous climate disruption is possible, but we are not stopping it.

You might think that natural changes in climate occur slowly over time. However, it doesn’t always happen that way. Sometimes, like at the end of the last ice age, change speeds up because of feedback cycles. For example, the whiteness of the snow on glaciers in the North and South Poles are important. They reflect some of the sun’s heat back into space. When glaciers at the poles melt, there is less area of whiteness to reflect heat. Instead, the heat is absorbed into the land and water. These areas warm, causing more melting of the glaciers. The glaciers then reflect even less heat. The feedback cycle continues.

It’s not only the atmosphere that has been changed by CO2 emissions. The chemistry of the oceans has changed as much of the CO2 in the air dissolves into the oceans. As more CO2 is absorbed into the oceans, it makes the water more acidic. Such activity endangers the life of certain creatures that form calcium shells. The shells break down under too much acid. Runoff from fertilizers and pesticides contributes as well. It causes strange buildup of harmful algae, called blooms. Widespread overfishing threatens underwater species worldwide. Our production and use of plastics are also affecting the oceans and the creatures in it. It also takes fossil fuels to make plastics. The effects of that creation process are also worrying. Both large and microscopic pieces of plastic, as well as oil runoff and spills, enter the waterways. They become dangerous to life in our oceans, rivers, lakes, and streams.

More than just sea life is at risk. The biodiversity of all parts of the planet is declining faster than usual. Reports put the present rate of decline as between a hundred and a thousand times the normal rate. Up to half of all species face extinction in the twenty-first century. Many biologists believe the current extinction will rank as one of Earth’s six major ones.

Another way that humans are changing Earth’s systems lies in our man-made chemicals. These include drugs, pesticides, plastics, and fabrics. Earth is absorbing these chemicals. The side effects are unknown right now.

Nuclear energy is another powerful force that humans have developed. Radiation in the environment has built up from nuclear bomb testing and use. It has also been released from nuclear energy waste and accidents. All of it has affected the Earth’s environment. The United States first tested and then used nuclear bombs as weapons in 1945. Several nations have performed similar tests, aiming to obtain nuclear weapons. In addition, increased levels of radiation on Earth have resulted from nuclear power waste and the fallout from nuclear disasters. Three Mile Island (US), Chernobyl (Ukraine), and Fukushima (Japan) are just a few. Exposure to radiation can damage or transform the cells of all living organisms.

The evidence above comes from biologists and climate scientists. But geologists have a very specific way of determining historical periods. They look for evidence in the rocks, or in layers of mud that will become rock. And even in the mud, they are finding evidence of environmental harm. Worldwide sediments contain radiation from atomic bomb testing in the 1960s. Similar evidence of chlorine from bomb testing and of mercury associated with the burning of coal also exists in ice-core samples.

Environmental historians support the claims of geologists. Scholar John McNeill wrote an environmental history of the twentieth-century world. It’s called Something New Under the Sun. In it, he asserts that “the human race, without intending anything of the sort, has undertaken a gigantic uncontrolled experiment on the Earth.”

Going forward

There are differing opinions about what these changes might bring. Can humans overcome them? James Lovelock is an English scientist. He believes that humans are no longer able to control change. Lovelock thinks the planet will be returned to some kind of necessary balance. It may not support much human life. According to Lovelock, the best we can do is try to adapt to the changes.

Others believe humans are clever enough. Maybe we can find our way out of any tight spot. As a society, we can use our group learning to create new technologies and new solutions. In fact, human communities have survived previous disasters. Why can’t we do it again?

Geologists continue to debate other questions: When did the Anthropocene begin? How do we know when we have reached the critical point of human influence on the Earth? Just considering these questions has allowed scientists to examine modern change. Meanwhile, people have to face this turning point in Earth’s history. Human decisions made in the near past and in the near future will determine the direction of life on our planet.

Many leading scientists and journalists believe that we have at most 10 years to change our destructive behavior. We must put new technologies into place, they say. Otherwise, our planet’s life-support systems could break down. It will take the commitment, new ideas, and cooperation of most humans on the planet to safely make these changes.

1 Another possible title for our latest geologic epoch is Capitalocene. It was first suggested by Andreas Malm, a human geographer. Malm focuses on humans’ use of capital (money) and fossil fuels in the industrial age. He says they’ve led toward a new period in history.
2 In fact, geologists have recently determined a new age of the Holocene epoch: The Meghalayan. It began 4,200 years ago with a global drought that lasted 200 years. “The Meghalayan is the first formal geologic time interval in Earth’s 4.6-billion-year history that began at the same time as a global, climate-driven cultural event” (Geiger, 5).
3 “The global average atmospheric carbon dioxide in 2017 was 405.0 parts per million (ppm for short)” (Lindsey). It has a “range of uncertainty of plus or minus 0.1 ppm. Carbon dioxide levels today are higher than at any point in at least the past 800,000 years.”