Space, Time, Mass: Interscalar Vehicles for the Anthropocene

The Anthropocene epoch marks a change of state: from an empty world to a full one, from humanity as one inhabitant of Earth among many to humanity as terraformer, creator of a global technosphere analogous to the biosphere and atmosphere.1 Like the biosphere, the technosphere (including its human components) ingests energy, materials, water, and information. It transforms them and generates wastes, but for the most part, unlike the biosphere, does not recycle them.2 Attempts to control it often end in failure, as some human components resist and the overall system finds other ways to meet its “needs.”

We dominate nature, but given the damage—from rapid climate change to the collapse of flying insect populations to the sixth mass extinction of species—“mastery” seems an odd descriptor of our relationship to Gaia. Human institutions appear not merely incapable of applying the brakes to self-destructive trajectories, but actually bound to servitude in the interests of the technosphere. Neither individual altruism nor democratic governance seem to offer realistic ways to assume responsibility for the planetary future—no matter how frantically scientists, activists, young people, and the occasional politician assert that we are “running out of time,” that we have “fifteen years to save the planet,” and so on. Knowledge won’t save us, but some of us will feel better knowing why we didn’t make it. And it might just help us fight.

Banana for Scale

Sensing the Anthropocene means grasping a myriad of scales, most of them beyond anyone’s direct experience, intuition, or control.3 Anthropogenic climate change is only one aspect of the Anthropocene, but it’s a major one. Scale is Lesson #1 of Climate Science 101. How do we visualize, imagine, and think with scales of space, time, energy, and mass? According to Gabrielle Hecht, we need “interscalar vehicles.”4

Interscalar vehicles for spatial scales seem easy enough. In social media, images include a coin, a banana, or a person “for scale,” enrolling familiar objects as units of measure. But visualizations that reach beyond the ordinary scale of human perception rapidly arrive at paradoxes. The impossible, literally fantastic visualizations of the 1977 film Powers of Ten by Charles and Ray Eames implicitly placed viewers in an ascending spaceship, flying upward from a picnic in the park, then zooming out to the edges of the universe, transcending the Einsteinian limits of speed. Zooming in, Powers of Ten compressed the viewer into a submicroscopic point, descending to the scale of subatomic particles: impossible, yet comprehensible, because the interscalar vehicle maps directly to real experiences of travel.5 In the first decade of the 2000s, Google Earth, Google Maps, and Google Street View democratized the interscalar zoom, enabling anyone with a web browser to experience impossible voyages of their own. We could view an entirely cloudless Earth, composed from tens of thousands of (temporally unsynchronized) satellite photographs, then swoop down in seconds (at speeds that would pancake a living person) to rooftops, then drop to street level to view our neighbors’ front doors.

For climate scientists, straddling scales like these is a routine aspect of the daily job, running the gamut from the molecular to the solar system. Earth’s land and ocean surfaces absorb solar energy hurled across ninety-three million miles of mostly empty space, then re-radiate it at different wavelengths, which are in turn absorbed and then re-radiated almost ad infinitum by molecules in the atmosphere, trapping heat. Water evaporates, travels as clouds, condenses into rain, trickles into aquifers, and flows into lakes and rivers. Heat, salt, and freshwater circulate around the globe in vast ocean currents.

Traversing the Anthropocene’s temporal scales requires a different kind of vehicle. Relating present experience to past and future time is supremely challenging for human beings. In youth, weeks and months seem interminable. Events that occurred before one’s birth might as well have happened in the Stone Age. Maturity, parenting, and the study of history bring longer-term perspectives to some, though many remain frozen in, or nostalgic for, the glorious eternal present of their youth. Meanwhile, the built environment of modern societies carries the past into the present and the future—in the form of architecture, energy systems, networked services, capital debt, long-lived institutions, and social/racial contracts—creating colossal path-dependent inertia that blocks radical change.6

Concepts like the technosphere and the Anthropocene attempt to capture the entanglement of human history with planetary change. They focus (for good reason) mainly on urban, engineered environments, but those have existed for barely the blink of an eye in geological time. Even Stewart Brand and Danny Hillis’s visionary project, the Millennium Clock or Clock of the Long Now (an interscalar vehicle if ever there was one), measures human time only on a scale of 10,000 years before and after the year 2000.7

Climatic time encompasses all these scales and more. Storms form, move, and morph on scales of minutes to hours or days. Seasons last for months. Year to year, ocean cycles like the multi-annual El Niño–Southern Oscillation govern global weather patterns. Periodic swings in the Pacific Decadal Oscillation can take, well, decades, as their name suggests. What scientists call “climate” is formally defined as averages of weather over periods of at least twenty years. The climatic changes of most concern—global heating, sea level rise, melting glaciers—are taking place over decades, but will persist for centuries. Over millennia, variations of the northern hemisphere’s exposure to the sun interact with the natural carbon cycle to initiate ice ages and interglacial periods. Ice core records bear witness to recurrent ice age cycles throughout the last 2.6 million years, “paced” by interacting orbital cycles with periods between 41,000 and 100,000 years.8 Reaching even further back, changes in Earth’s atmosphere, the positions of continents, solar output, and other factors caused ice-free “hothouse” intervals with sea levels much higher than at present.

Climate and Human Time

Self-focused as we inevitably are, even the last few decades of human history seem to most people a vast and deep temporal sea, and indeed there’s much to know and to tell. Yet our past as a species is much, much deeper.9 Genetically modern humans have existed for around 300,000 years, through two ice ages and two interglacial periods. Human hunter-gatherers first migrated out of Africa around 90,000 years ago. They went on to thrive in nearly every landscape and climate on Earth, from the tropics to the Andes and the Arctic. At the dawn of the Holocene, the Earth was already fully inhabited by around ten million hunter-gatherers.10

Those societies altered many ecosystems. Some engaged in large-scale land management, for example, through selective burning of grasslands and forest undergrowth. They hunted numerous large mammal species to extinction, and managed the numbers and locations of many other species for their own benefit. Some scientists have suggested that human activities—including those of other, premodern species of the genus Homo—may have begun to influence climate long before agricultural civilization, during a “Paleoanthropocene” period extending back several tens of thousands of years. The logarithmic scale of the figure counterintuitively foreshortens that past—and even more so the world that came before it—but is the only way to represent very long periods of time on a two-dimensional chart.

Anthropocene and "Paleoanthropocene,” presented on a logarithmic time scale. This graph is an example of the reversed, present-to-past time axis often used in paleoclimate studies. Source: Stephen F. Foley et al., “The Palaeoanthropocene – The Beginnings of Anthropogenic Environmental Change.”

In comparison to the 300,000-year history of Homo sapiens sapiens, the 12,000-year Holocene epoch is brief. Yet it encompasses the entirety of agricultural civilization, including virtually all written records, the rise of city-states and nations, most of what is today called “technology,” the ongoing population explosion that started in the nineteenth century, and the present-day sixth mass extinction of species caused by us. 11 Although the phrase “Holocene climatic optimum” technically refers only to the warm period from 9500–5500 years before the present, in fact, most of the epoch has exhibited remarkable temperature stability.12 This suggests that the agricultural civilizations which seem so normal to us, their inhabitants, might never have developed without this unusually steady, relatively warm climatic state.

A 100,000-year proxy record of temperature from the Greenland Ice Core Project (GRIP), showing the remarkably stable Holocene temperatures (top right). (NB: this is a local record, not a true global average.) Image: Will Steffen. Data sources: GRIP ice core data (Greenland) for O-18 (oxygen isotope strongly correlated with temperature; human species history from Oppenheimer, Out of Eden (2004).

Further, only in the last century or so have human activities truly attained the scale of geological forces. Most of that dubious achievement has occurred since the 1945 explosion of the first nuclear weapon, often cited as inception date for the Anthropocene. That century amounts to a mere 0.03 percent of our species’ time on Earth so far. If the species history of Homo sapiens sapiens were a single human lifetime—say eighty years—less than the last three years of that lifetime were spent in the Holocene, and only a month of it in the industrial age. Only the last week was lived in the Anthropocene.

Time Machines

H.G. Wells’s 1895 novella The Time Machine established a perennial fixture of science fiction: a device that allows individuals to jump instantaneously from their present to a particular moment in the past or future. A Wellsian time traveler can inhabit a past or future reality at any distance from the present, all while retaining their own, temporally foreign perspective. The traveler’s experience of the trip may be hallucinatory or stressful, but it is brief, and the travel experience itself is never the point; once arrived at the destination, time passes as usual in the traveler’s experience. Thus, the traveler sees only the future results of change, or visits some prior state that evolved into the traveler’s present, but never witnesses the actual process of change itself. Perhaps this is why so many time-travel stories, novels, and films focus on butterfly-effect moments, where some small action by the traveler subtly or dramatically alters the entire future.13 This kind of time machine can’t dramatize large-scale, slow, complexly interacting forces.

“Histories of the future” are another, more fact-based type of time machine. This approach looks back at what people of some previous era thought the future might hold. Many focus on sociotechnical imaginaries and techno-futurism. We’re all familiar with “where’s my flying car?” and similar internet memes, as well as phenomena such as general artificial intelligence and fusion-based nuclear power, both of which were twenty years away when first imagined in the 1950s and likely still remain twenty years in the future today. Academic histories of the future illustrate both prognostications that turned out to be accurate and others that failed.14 They serve as cautionary tales, warning against a sweeping technological optimism even as they also show that many things once merely imagined have actually come to pass.

Today, climate science is old enough to write its own history of the future. Previous model projections of climate futures can be compared against what actually happened in the more than five decades since the first of them were made. In 2021, the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6) evaluated the projections of major climate models since 1970.15 Instead of the usual graph of temperature against time, this assessment graphed temperature against radiative forcing. The reason for this was that in order to calculate the future of temperature, past modelers had to project (estimate) future changes in greenhouse gas emissions, aerosols, and other radiative forcing factors. Naturally, these estimates were never exactly right. The retrospective test in AR6 therefore plotted each model’s temperature projections against observed radiative forcing. This method accounts for any differences between the modeler’s projected time-evolving radiative forcing and the radiative forcing that actually occurred. As it happens, most models projected temperature change quite well.

Top: Original model projections of temperature vs. time. Bottom: Same model projections of temperature vs. radiative forcing. Original caption: Fig. 1.9 of IPCC AR6 WGI. Original caption: Assessing past projections of global temperature change. Projected temperature change post-publication on a temperature vs. time (1970–2020, top panel) and temperature vs. radiative forcing (1970– 2017, bottom panel) basis for a selection of prominent climate model projections (taken from Hausfather et al., 2020). Model projections (using global surface air temperature, GSAT) are compared to temperature observations (using global mean surface temperature, GMST) from HadCRUT5 (black) and anthropogenic forcings (through 2017) from Dessler and Forster (2018), and have a baseline generated from the first five years of the projection period. Projections shown are: Manabe (1970), Rasool and Schneider (1971), Broecker (1975), Nordhaus (1977), Hansen et al. (1981, H81), Hansen et al. (1988, H88), Manabe and Stouffer (1993), along with the Energy Balance Model (EBM) projections from the FAR, SAR and TAR, and the multi-model mean projection using CMIP3 simulations of the Special Reports on Emission Scenarios (SRES) A1B scenario from AR4. H81 and H88 show most expected scenarios 1 and B, respectively. See Hausfather et al. (2020) for more details of the projections. Further details on data sources and processing are available in the chapter data table (Table 1.SM.1).

Models are not physical experiments, but in the absence of an actual “control Earth” on which to perform such experiments, they are the next-best alternative.16 One key experiment compares models of climate that include realistic anthropogenic inputs (greenhouse gases and aerosols) since 1860 with models that omit those inputs, as if there had been no human activity. In these experiments, no models could reproduce the strong warming trend since 1970 without the anthropogenic inputs. Thus, models serve as time machines, projecting potential futures and avoided worlds.

Top: CMIP model ensembles including time-evolving anthropogenic inputs of the 20th century. Bottom: CMIP ensembles run without anthropogenic inputs. Black line in both graphs is observations; blue and red lines are model ensemble averages. Source: Adapted from Figure 10.1, IPCC AR5, Working Group I.

The climate scientist’s most-used time machine is, of course, the two-dimensional x-y graph, with time virtually always represented on the x-axis. The x-y graph has many virtues. It can show dates, intervals, amounts, and rates of change, all at once. It’s simple, it’s easily presented on page or screen, and it’s used throughout the sciences. From the scientist’s point of view, the x-y graph is as much a universal language as mathematics.

A typical x-y graph used in climate science. Source: Berkeley Earth, April 2025.

But this way of representing time is not actually universal, not even in the sciences. In most x-y graphs, the time axis runs from time “t” on the left to time “t+n” on the right. Yet in paleoclimatology, the time axis was traditionally reversed, running from time “t” to time “t-n” (present to past), as if looking backward into the past from the origin point of the graph. Although this convention is dying out under pressure of the need to present paleoclimate data alongside historical information, it demonstrates one scientific community’s alternative way of visualizing time.

Example of a paleoclimate x-y graph, with the time axis showing time from present to past. The notation “ka” refers to kilo-annums, i.e. thousands of years. Original caption: Compilation of North Africa paleoclimate records for the last known period of activity of the Timiris Canyon (Skonieczny et al., 2015, Figure 2).

Another interscalar vehicle is the time-lapse film, which speeds up slow changes to render them perceptible. James Balog’s Extreme Ice Survey, for instance, created videos of retreating glaciers using seventy-two time-lapse cameras placed at glacial termini, photographing at the rate of just 8,000 frames a year. Balog had to move some of his cameras multiple times to keep up with the pace of melting. Here, the point is precisely to witness change itself. Months or years compress into minutes, allowing the viewer to view processes that happen too slowly for human beings to perceive.

An animated spiral GIF displaying global temperature averages month by month since 1850. Graphic: Ed Hawkins.

The time-lapse technique can also animate time-series data.17 A NASA animation presents the global temperature record from 1880–present, smoothed as a five-year running average. This animation, which lasts just thirty seconds, is not merely a representation of global temperature, but a spectacular moving image of industrialization and globalization powered by fossil fuel combustion.

Animation of global temperature anomaly data, 1880–2020, 5-year running means. Baseline period is the 1951–80 average. Source: NASA Goddard Space Flight Center, visualization: Lori Perkins.

Finally, the time-lapse animation can also visualize divergence between two modeled future states. In 2015, NASA created an animation showing changing stratospheric ozone concentrations between 1974–2065, based on data through 2015 and on model projections thereafter. The animation includes two maps. In one, the ozone hole develops (in blue) over Antarctica, then begins to shrink following the 1987 ban on ozone-depleting chemicals under the Montreal Protocol. The other shows the “world avoided,” modeled as if the Montreal ban had never occurred. Here, ozone concentrations continue to decrease, first at the poles and then over the entire planet. This illustrates one of the most powerful roles interscalar vehicles can play: showing possible planetary futures playing out side by side, making visible the interactions of transparent gases in distant places and speeding up the processes of change to render them perceptible.

Model animations used to compare the past and future of the stratospheric ozone layer with (top) and without (bottom) the regulation of ozone-depleting substances under the Montreal Protocol. Cl ppb = chlorine measured as parts per billion. Source: NASA Scientific Visualization Studio, 2015. Visualization: Trent L. Schindler.

So far, all time machines have visited only the past. But what about the future? The orbital and axial cycles that brought Earth’s ice ages will never cease. Prior to the twentieth century the Holocene Climatic Optimum had already given way to a creeping temperature decline under their influence. When will the ice return?

On the time scale of Homo sapiens, the answer is basically “never.” It is predicted that Anthropocene changes to the planet will prevent another ice age for at least the next 50,000 to 500,000 years. Meaning, ultimately, “it is the Holocene epoch at only 11,700 years duration that will appear as the ‘blip’ in the Geological Time Scale, a brief interval when complex, settled human societies co-existed with, but did not overwhelm, a stable Earth System.”18

Stewart Brand’s “long now” (bottom), set against the human-hospitable climate of the Holocene (top left) and the “alien” Anthropocene climate that will emerge by 2500 under medium-to-high IPCC emissions scenarios (RCP4.5 and RCP6.0, top right). Source: Brand, The Clock of the Long Now; C. Lyon et al., “Climate Change Research and Action Must Look beyond 2100.,” Glob Chang Biol 28, no. 2 (2022): 349–61; Alex Dunhill et al., “Our Climate Projections for 2500 Show an Earth That Is Alien to Humans,” The Conversation, September 26, 2021; Matthew B. Osman et al., “Globally Resolved Surface Temperatures since the Last Glacial Maximum,” Nature 599, no. 7884 (November 11, 2021).

The next 10,000 years of Earth history—and human history—will take place in the Anthropocene. None of our scientific time machines can tell us much about the future beyond 2500. Although humanity can still escape the worst consequences through decisive action within this century, the outlook to that point is grim.

The Weight of the Anthropocene

The Anthropocene is heavy, physically and metaphorically. In physical terms, the Anthropocene is matter in motion. It is scrapings from Earth’s crust shifted, eroded, burned, vaporized, reordered, combined, recombined, discarded, and sedimented. It is steel, concrete, asphalt, plastic, and glass. It is plants grown, fertilized, harvested, consumed, fed to domestic animals in staggering quantities, sawn into lumber. It is sawdust transformed into toilet paper and shiploads of particle-board furniture. And it is living creatures, most churned out in factory farms: cattle, pigs, chickens. Ten thousand years ago, 99 percent of all mammals by weight, both on land and in the ocean, consisted of wild creatures. Today, wild mammals make up just 4 percent by weight. The eight billion humans now alive constitute 36 percent, far surpassed by domestic livestock at 60 percent of the total.

Where can we find an interscalar vehicle for mass? Space and time are hard enough to grasp, but at least metaphors and experiences of travel and zoom lenses provide usable analogs. Weight is another story altogether: hard to visualize, even harder to grasp intuitively. Most people’s experience of moving heavy objects tops out at less than a hundred kilograms. But even things of similar size can weigh dramatically different amounts. Buildings, pavement, and cities seem utterly immovable, yet when they are destroyed, whether in peacetime or in war, the rubble of their destruction eventually gets lifted and taken “away,” wherever that is, with the help of powerful machines. Diggers and trucks the size of houses routinely rip out and carry away megatons of metal ores. Meanwhile, other things like air, smoke, or carbon dioxide seem weightless but are not. A typical coal-fired power plant emits 5,000 tons of particulate matter and three million tons of carbon dioxide in a year. Even our “marvelous clouds” are dense with matter: a typical cumulus cloud weighs half a million kilograms.

Finding an interscalar vehicle to convey the scales of the Anthropocene’s mass requires comparing highly disparate objects. Physical size (spatial scale) is almost useless for measuring mass. So here is a kind of Harper’s Index of Anthropocene mass, illustrated with a simple bar chart and a logarithmic scale: a rusty old jalopy, for sure, but an interscalar vehicle nonetheless:

• All spent nuclear fuel: 390,000 tons
• A cumulonimbus (thunderstorm) cloud: 1 million tons
• Palace of Parliament, Romania (world’s heaviest building): 4.1 million tons
• New York City: 347 million tons 
• All wild mammals: 20 million tons
• All humans now alive: 400 million tons
• All domestic animals: 630 million tons
• All passenger cars: 2.4 billion tons
• Annual global concrete production (2019): 34 billion tons
• The biosphere (all biomass on land and in the ocean, including plants, animals, and single-celled organisms): 1.1 trillion tons dry weight
• The technosphere: 1.17 trillion tons of materials “actively in use by humans”
• All carbon dioxide emitted by human activity in 2024, including land-use change: 42 billion tons
• All carbon dioxide emitted by human activity since 1750, including land-use change: 2.5 trillion tons
• The Thwaites “Doomsday” Glacier in Antarctica: 445 trillion tons

An index of Anthropocene mass. Logarithmic scale; each increment is 100x the previous one. Chart by author, using Claude AI. Data sources: Yinon M. Bar-On, Rob Phillips, and Ron Milo, “The Biomass Distribution on Earth,” Proceedings of the National Academy of Sciences 115, no. 25 (June 19, 2018): 6506–11; “Making Concrete Change: Innovation in Low-Carbon Cement and Concrete,” Chatham House – International Affairs, August 3, 2022; Emily Elhacham et al., “Global Human-Made Mass Exceeds All Living Biomass,” Nature 588, no. 7838 (December 2020): 442–44; Tom Parsons et al., “The Weight of New York City: Possible Contributions to Subsidence From Anthropogenic Sources,” Earth’s Future 11, no. 5 (2023); Jan Zalasiewicz et al., “Scale and Diversity of the Physical Technosphere: A Geological Perspective,” The Anthropocene Review, 2016.

No banana for scale here: these weights only fit on a bar chart with a logarithmic scale, where each increment is 100 times the previous one. Such charts are useful for science, but remain completely unintuitive for most of us.

The weight of the Anthropocene utterly transcends its physical mass. Its burdens are infrastructural, financial, social, political, psychological. We live inside its concrete and steel, cars and aircraft, heat and light, the infrastructures making up our techno-natural background.19 Most of those infrastructures were built in and for the twentieth century climate, now long gone. Today, the fury of increasingly extreme weather has begun to damage and destroy them. Repairing or replacing them will only become more challenging and expensive in the coming decades.20 As a result, generalized climate risk has become a primary concern of economic experts and reinsurance companies. Insurance against extreme weather, floods, and forest fires is rapidly becoming harder to get and more expensive. The private home insurance market is collapsing in the most affected places, such as Florida and California.21

Survey of 1200+ experts, Sept–Dec 2022. Source: “Global Risks Report” World Economic Forum, 2023.

Yet despite many decades of scientific research, merely accepting the reality of anthropogenic climate change remains a bridge too far for many, a consequence of the path of dependence on fossil fueled infrastructures and the lifeways that go with them. Denialism, initially a rear-guard action of the fossil fuel industry in the 1990s, has mushroomed into an industry in the Anglophone world.22 As a result, climate governance at every level contends with reactionary “de-governance”: policy reversals and roadblocks limiting or even reversing effective action.23 Case in point: the Trump administration’s second withdrawal from the 2015 Paris Agreement and its savage assault on nearly all domestic environmental regulations, including the landmark Inflation Reduction Act of 2022, the USA’s only major federal climate legislation.

Freeze, Fly, or Fight

The emotional and psychic weight of these concerns and failures can hardly be underestimated. Psychologists and therapists formally recognize the toxicity of “eco-anxiety”—a “chronic fear of environmental doom”—on mental health, with special concern for that of children.24 Freeze: failure and fear can be paralyzing; many respond by going quiet, or numb, or both. Fly: many others turn away or hide, choosing to ignore the problem.

But the best antidote to anxiety is action: fight. Traversing scales of space, time, and mass can help us to visualize, to think, to sense Anthropocene phenomena far beyond any possible individual experience. Interscalar vehicles can open into compelling narratives of future time, revealing the scale of necessary change by exhibiting the immensity of past activity that brought humanity to this point. We need stories of continuity with our hunter-gatherer ancestors and with the climates and landscapes of the “distant” past. Some such stories are already being told in “big history” and “zoom” courses (zoom as in lens, not screen). As for the future, cli-fi novels like Kim Stanley Robinson’s New York 2140 (2017) and The Ministry for the Future (2020) and videos such as the Apple TV series Extrapolations (2023) dramatize near-term climate futures and imagine potential adaptations. To fight effectively, human history as we know it must be re-imagined and re-learned, oriented toward planetary processes, deep time, and interventions as massive as those that created the technosphere—which seems all-powerful, but remains in fact a human creation that humans can act, on enormous scales, to reorient and repair.