Age of Humans has Dawned

By Tim Lucas. Photography by Jared Lazarus

DAN RICHTER and PETER HAFF believe we’re living in a new age, one that is unlike any that has come before it.

And for better or worse, they say, it’s of our own making.

“There is compelling evidence that human activity has become the driving force shaping our planet,” says Richter, professor of soils and ecology.

Daniel Richter, PhD, Professor of Soils and Forest Ecology, teaches Nicholas School of the Environment students about Calhoun soil in Duke Forest.

It’s time that we recognized this change, Richter and Haff say, by formally acknowledging that a new geologic epoch, the Anthropocene, or Age of Humans, has dawned.

This January, Richter and 23 other scientists published a widely cited paper in Science that presented comprehensive evidence that human actions have left measurable signals in Earth’s geological strata and that these signals—which occur on a global scale—are different from those of the relatively stable Holocene epoch, the previous 11,700-year period that allowed human civilization to develop.

The great global carbon, nitrogen and phosphorus cycles have been substantially modified, the analysis shows. Plastics and other manufactured materials with long lifetimes are showing up in sediments worldwide. The rates of erosion and sea-level rise are accelerating. Concentrations of greenhouse gases are rising in our air and oceans, exacerbating human perturbation of the climate system. Against this rapidly changing landscape, invasive species are thriving, and speeding the rates at which others go extinct.

Essentially, humans are playing a role once reserved for geological forces such as wind, water, fire or ice. At the same time, our machines are becoming more biological, says Haff, professor emeritus of geology and civil and environmental engineering.

We’re creating technologies that can think and communicate with one another, and react in real time to the world around them. Wireless connectivity has allowed these technologies to form new kinds of hybrid ecosystems that turn our farms and factories and homes and cities into responsive environments. The lines between biology, geology and technology are blurring.

In 2014, Haff published a pioneering paper in The Anthropocene Review that introduced a new concept, the technosphere, to describe this emergent Earth system. The technosphere, he explained in the paper, is a quasiautonomous system that is every bit as real and relevant to global change as the biosphere. It encompasses not just nature but also humans and all their inventions and institutions— everything from cars and computers to satellites and cyberspace. It has its own definable behaviors and internal dynamics, which humans currently drive but don’t really control. And it is evolving at a speed that leaves biological evolution in its dust.

Peter Haff, Professor Emeritus of Geology and Civil and Environmental Engineering, Duke Nicholas School of the Environment, studies the neoenvironment, or the total environment in which we live – the sum of the natural, human, and technological systems and processes that surround us. 

Through their scholarship on these issues, as well as their leadership on the international Anthropocene Working Group, Richter and Haff are helping spearhead the push for a new paradigm in how we view and ultimately manage human impacts on the Earth.

DukeEnvironment recently sat down with them to discuss their work, its implications for environmental science and policy, and how, or if, humans can forge a future that is both sustainable and worthwhile in the face of the rapidly evolving technological and natural changes we’ve helped set into motion.

Question: Based on the unique signals you’re finding in the geologic record, when did the Anthropocene start?

RICHTER: “The most widely agreed upon date is likely the mid-20th century, when unique biogeochemical signals from nuclear bomb fallout, plastics and other manufactured materials first began appearing in sediments, ice and ocean water worldwide.

“But you could argue that the earliest signals of humandriven functional change in the Earth system date back hundreds to even thousands of years to the Stone Age, when humans first began using small tools to drive the mass extinctions of other species during the Late Pleistocene. The bones of those extinct species are found in the fossil record.”

Question: Given that the Holocene Epoch is only 11,700 years old, isn’t it a little premature to be recognizing the start of a new geologic era?

RICHTER: “That’s the subject of vigorous scientific debate. From my perspective and that of many colleagues, the biogeochemical signals we’re finding and the functional changes we’re observing are large, persistent and distinct enough to indicate we’re in a new geologic age. So, no, it’s not premature.”

Question: But not all scientists agree, right?

HAFF: “As scientists, we all agree that something new is happening in the Earth system. Large forces are afoot. The question is whether they are distinct enough from the forces that shaped Earth in the past to leave a unique, global and lasting geologic signature. The answer is yes.”

RICHTER: “Building consensus takes time. I’m confident that as further evidence from the geologic record comes to light, more people will reach a conclusion similar to ours. There is already widespread support for it, not only in the sciences but also the humanities and social sciences.

“As a geologist, I’m trained to be skeptical. But when I look at the scale of change that is occurring now, I’m awestruck at how significantly we are changing Earth’s biogeochemical processes. Plants are photosynthesizing differently now than they have in the past—because of us. Floodplains are inundated with human-eroded sediments from uplands, transforming valleys throughout the world—because of us. Our planet is no longer a natural system. It’s become a hybrid system, driven by humans as well as by nature.

Question: So what’s the next step in the scientific consensus-building process?

RICHTER: “We need to keep searching the geologic and anthropological record for additional evidence. I think we’ve only begun to scratch the surface of what’s out there. We need to expand the scope of our work to the humanities and social sciences, where there is an incredible level of interest in this. We also need to expand the scope of our research geographically, through improved use and funding of resources like the global Critical Zone Observatory network.

“Ultimately, to gain formal recognition of the Anthropocene we’ll have to convince the members of the International Stratigraphy Commission, who can be a tough and skeptical bunch. They’re expected to meet and vote on the issue sometime this year or next, and we’re hoping our research helps persuade them.”

HAFF: “In my opinion, it’s not a data problem. It’s a psychological issue.”

Question: Do you mean that skeptics think the proposed recognition of the Anthropocene—and even its name itself—is more about symbolism than science?

HAFF: “It’s partly that, yes, but also it’s that what we’re proposing requires a fundamental shift in how we view the Earth system and humans’ role in it.”

“The world’s technological systems and the human population are all linked together into a combined system that I call the technosphere. It’s a hybrid Earth system. “With the advent of this rapidly evolving global system, the lines where biology and geology end and technology starts are becoming less defined. The Earth no longer just makes mountains and valleys. It also makes hospitals and highways.

“So what does that mean for humans?

“It raises difficult questions that extend beyond the traditional scope of the geosciences. They require a paradigm shift in our understanding of how the Earth system operates, the degrees of freedom humans have to operate within it, and how much control we exert over the system itself.”

Question: This could be interpreted as presenting a fairly pessimistic outlook about our future. Is there reason for hope we can turn things around in time?

RICHTER: “Absolutely. It all comes back to degrees of freedom at the personal or local scale, correlated to the scale of the system you’re dealing with. What I love about Peter’s work is that it emphasizes that the greatest resource we have—and the best opportunity for positive change— starts at these personal or local scales, not at the system-wide level.”

HAFF: “To me, a more important question than climate change is the role of people in an increasingly technological world.

“Humans are being marginalized by technology. Just as Earth’s natural critical zones are being squeezed by highways and buildings and other infrastructure, so too are the small, unscripted places in the technosphere being squeezed. These are the places where free-flowing human interactions and emotions can thrive, independent of the larger system’s control. It’s where much of human purpose, ethics and intentionality lives.”

Question: And these spaces are at risk?

HAFF: “They’re being squeezed, yes. The technosphere operates like any large dynamic system. To preserve itself, it requires that most of its parts, at least some of the time, have to support its operation. This can be called the rule of performance. It also aims for efficiency. If its parts, including humans, are not performing efficiently they become obsolete and eventually discarded as new technologies appear.

“But there is also a reciprocal rule that governs the way the technosphere operates. This is the rule of provision. It requires that the system provide its parts with an environment in which they can do their jobs, so they can contribute to the system’s operation and continued preservation. It’s a two-way street, like supply and demand. But humans have to perform.”

Question: So the technosphere needs us?

HAFF: “That’s a decidedly human perspective! The technosphere is autonomous and doesn’t care what happens to us. But I don’t think it will squeeze us out, either, as long as we fulfill a uniquely useful function and support its operation. As long as we perform better than technology, we have some job security.

“It might seem that conceptualizing the technosphere from this physical perspective rules out the importance of human initiative, self-direction and purpose. But it doesn’t. It just provides an explanation of the physical conditions under which these qualities can express themselves.

“That’s what I like about the idea of the Anthropocene. It encompasses the unity of people, technology and geology. It’s an idea that helps bring some clarity to what’s happening in the world now.”

Question: In light of all of this, how do we move forward to forge a sustainable and worthwhile future?

HAFF: “As individuals, as a school and as a society, we have to approach this challenge with humility. A focus only on human self-interest is not really in our own best interest because it discounts the needs of the technosphere, and any solution that fails to address its needs as well as our own is likely to fail.”

RICHTER: “The trick is to find a way to bring about worldwide changes that align the goals of the individual with the goals of the larger collective, and with the needs of the biosphere and technosphere. That’s a tall order, but it’s not insurmountable.

“The greatest opportunity for solutions starts by changing our actions at the personal or local scale, where we have the greatest degrees of freedom. It all builds from there.

“A first step would be to recognize that human activity has become the driving force shaping our planet. Recognizing the Anthropocene would force us to take a broader, more interdisciplinary focus in our study of the Earth system. It brings in the humanities and social sciences, and underscores the different way in which we are now affecting Earth’s biogeochemical processes. It’s a new age, a new system, a new planet. That’s an important message to the stratigraphers who study the Earth’s dynamic rock record, and also to us all.”

Tim Lucas is senior writer for Dukenvironment magazine and is the Nicholas School’s director of marketing communications.