Thomas Homer-Dixon
The Version of Record of this article was published in Vox.
Image: Claire Merchlinsky for Vox
Is the world facing a “polycrisis”? Is there even such a thing?
First coined in the late 1990s, the term entered the zeitgeist earlier this year, when “polycrisis” became the neologism du jour at the most recent World Economic Forum meeting in Davos. Its use evoked the world’s current tangled mess of problems — pandemic, war, climate extremes, energy shortages, inflation, rising authoritarianism, and the like — and the term caught on.
Inevitably, critics have multiplied since then — as have crises, such as the violence now convulsing Israel and Gaza. Those on the political center and right say the polycrisis concept is nothing more than a fancy buzzword. Sure, a lot of bad stuff is happening in the world, but that’s always been the case. As historian Niall Ferguson has scoffed, the polycrisis is “just history happening.” For Ferguson and other critics, the concept merely recycles old alarmist, Malthusian tropes. We can count on well-established counterbalancing forces, they argue, including free markets’ price mechanism, to keep today’s crises from causing widespread harm.
Meanwhile, critics on the left say that the polycrisis idea distracts attention, perhaps deliberately, from the real driver of humanity’s traumas: relentless, predatory globalized capitalism.
One is the assertion — implicit in the notion of polycrisis — that what’s happening today is essentially new. This idea particularly vexes critics on the political center or right, because it suggests that dominant economic and social structures need to radically change to accommodate our new reality. These critics would rather believe that humanity has been in similar circumstances before; and since we’ve coped well before (supposedly), we’ll cope again without changing things much.
Groupthink helps sustain this comfortable belief. Even Adam Tooze, the Columbia University historian who has been among the most thoughtful proponents of the polycrisis concept, makes the case for novelty only tepidly, saying the world exhibits a bewildering synthesis of long-established trends and new phenomena.
But in reality, new phenomena are now reconfiguring and even overwhelming old trends at an accelerating rate. We’ve moved so far and so fast outside our species’ previous experience that many elites don’t have the cognitive frame to grasp our situation, even were they inclined to do so.
To see how novel today’s world really is — and how this novelty is helping to generate today’s polycrisis — let’s compare humanity’s past and present state on four key measures. This list isn’t remotely exhaustive, but it’s easily enough to make the case.
The most basic measure is …
1. Total human energy consumption: Driven largely by soaring use of cheap fossil fuels, our energy consumption has increased sixfold since 1950. Since that date, we’ve consumed about 60 percent of all the energy we’ve produced in our species’ existence.
No other factor has so transformed the economics of human civilization. Prior to the first Industrial Revolution in the 18th century, societies used between half and three-quarters of their economic output to get the energy they needed; since 1950, that proportion has fallen to less than 10 percent.
And as we’ve metabolized immense quantities of fossil fuels, we’ve also transformed the physical and ecological face of the planet, most importantly by shifting …
2. Earth’s energy balance: From the evolution of modern humans to the 20th century, the amount of energy arriving on Earth from space (mainly visible light from the sun) was roughly balanced by the amount going back out (mainly in the form of heat and reflected light). But now less energy is going out than coming in, because our greenhouse gas emissions are trapping more heat in the atmosphere. The imbalance is at least 0.9 watts per square meter at the planet’s surface.
Perhaps that doesn’t seem like a big deal. But the extra energy adds up fast. It’s equivalent to placing a standard 1,200-watt hotplate turned to its maximum setting — enough to boil a quart of water in five minutes — in the middle of each patch of Earth’s surface the size of an average American lot. Aggregated across Earth’s entire surface, it’s the amount of energy that would be released by detonating 600,000 Hiroshima-size atomic bombs every day.
Injected into our oceans and atmosphere, this extra energy is not just heating things up, as we’ve seen with off-the-chart temperatures this past summer. It’s also revving up the planet’s hydrologic system — the cycle of water between Earth’s surface and the air — which in turn is supercharging the increasingly extreme storms, floods, droughts, and wildfires appearing everywhere now. It’s like we’ve unleashed a massive beast, a Behemoth or Leviathan, that’s rampaging across the planet’s surface. Each year, as more and more energy arrives at Earth’s surface than goes back out, we pump more energy into the beast — so it gets bigger and does more damage.
This change in the planet’s physical properties is causing knock-on effects on global food output, mass migration, economic growth, and civil stability that are already sucking trillions of dollars of wealth out of the global economy. All by itself, it’s enough to establish that humanity’s situation is now fundamentally different.
But we’ve also seen a huge increase in …
3. The human population’s total biomass: In the 125 years between 1800 and 1925, the world’s population approximately doubled, from 1 billion to 2 billion. In the near-100 years since, it has quadrupled again, to 8 billion, with a total mass of just under 400 million metric tons. Vastly higher energy inputs to agriculture — for mechanization, irrigation, fertilizer production, and the like — made this faster growth possible. Without fossil fuels, in other words, our population would be a fraction of what it is today. In fact, about a third of the carbon in our bodies, totaling about 3 kilograms on average, originated in the coal, oil, or natural gas we’ve collectively burned. The carbon atoms have passed from the atmosphere through our crops’ photosynthesis and into our bodies through food consumption.
Mushed all together, our total biomass would fill a cube about 750 meters on a side. That might not seem like much, except that we now constitute the second most massive single species on the planet. Cows come in first, with a total biomass about 5 percent larger than us. Sometime in the last two decades, as our population grew, we supplanted Antarctic krill for the No. 2 spot. (Both global warming and overfishing threaten to deplete krill biomass further.) Domesticated sheep, which are also a single species, rank No. 4.
By itself, growth in our biomass isn’t a reason for alarm. But it helps cause today’s polycrisis in combination with soaring …
4. Connectivity of the human population: Aircraft, container ships, fiber-optic cables, satellites, oil tankers, and pipelines are all conduits for unprecedented circum-planetary flows of matter, energy, organisms, and information. Between 1980 and 2020, the number of air passengers nearly tripled, to 1.8 billion annually; air freight increased sixfold, to 180 billion ton-kilometers per year; and internet usage rose from virtually zero to 60 percent of the world’s population. Between 1980 and 2022, the total value of world merchandise trade increased 12-fold to nearly $25 trillion (at current prices), while container port traffic has more than tripled since 2000, to almost 800 million 20-foot equivalent units in 2020.
Abundant fossil fuel energy and innovations such as containerization boosted this connectivity, by permitting ever-greater amounts of stuff to be carried along the world’s conduits at relatively low cost. The end of the Cold War in the 1990s was also essential, because it allowed international diffusion of neoliberal economic norms and institutions that supported globalization of trade. (Rivalry between the US and China is now weakening this regime.)
But the most vital cause of higher connectivity has been the ongoing collapse in the cost of communication. Decades of exponential improvements in computing power and in the communication systems that this power enables have driven the price of generating, storing, and distributing a bit of information to near zero. Billions of us around the world now carry in our pockets a computer that would have filled 50 Pentagons in the mid-1950s. We can use it to link almost instantaneously with nearly any of the other billions of computers. And because this communication is so cheap, we move among ourselves quantities of information that would have been incomprehensible barely more than a generation ago.
Discrete changes, one big polycrisis
Of the four changes I’ve highlighted, only the sharp increase in Earth’s energy imbalance is unequivocally a bad thing, at least for human well-being. But all four are markers of an unprecedented transformation in humanity’s circumstances — an explosive rise in human population, material consumption, connectivity, and global environmental impact beginning around 1950 that some scientists call the “great acceleration.”
The acceleration of overall change is important. Yet even more important are the less-recognized causal interactions among discrete changes like the four I’ve highlighted. And it’s these interactions that are generating today’s polycrisis.
Here’s an example. Scientists have shown that ecological, technological, or social systems that are both highly connected and highly homogeneous are especially prone to cascading failures — that is, to failures that resemble a row of dominoes falling over. High connectivity lets a disruption — for instance, a pathogen or external shock — move quickly from one part of a system to other parts; high homogeneity ensures the disruption’s impact is similar across those parts.
Think of a field planted with rows of genetically identical corn. The close proximity of the stalks ensures high connectivity, so a blight can easily jump from one plant to another. Their genetic homogeneity ensures that the blight will be equally harmful across all plants. This is a major reason modern industrial agriculture relies so heavily on pesticides.
The human population is now just like that field of corn. We’re a highly connected, largely genetically identical biomass, except in this case, we’re vastly more massive and our “field” extends across much of the planet’s surface. And, sure enough, we’re exhibiting a monocrop’s vulnerability to pathogens, so we’re using (and in some cases overusing) antibiotics and antivirals just the way we use pesticides on our crops.
Of course, because we’re a single species, we’ve always been genetically homogeneous, and for millennia we’ve also been somewhat connected by travel and trade, which is why humanity has long experienced pandemics. But the combination of our homogeneity with our recently multiplied biomass, and now our extraordinary connectivity, has created a qualitatively new situation. While in the 19th century, cholera took years to spread around the planet, and in 1918 influenza took months, now infectious pathogens travel to the other side of the world in weeks. Our species has become by far Earth’s most inviting medium for the rapid evolution and propagation of pathogens.
Climate change is playing a role, too. By disrupting habitats and forcing wild animals into closer proximity to our populations, it’s increasing the risk that pathogens not recognized by our immune systems will jump from animals to humans.
It turns out that the field-of-corn analogy also applies to our world’s financial systems, much of our shared technological and manufacturing infrastructure, and many of our food systems, because these systems are not only highly connected but also increasingly homogeneous. Globally networked corporations like Meta, Microsoft, Unilever, Cargill, and Tesla lower their costs and grow by standardizing their products across diverse national markets. Similarly, global institutions like the International Organization for Standardization or the Financial Stability Board increase their economic and political clout by bringing more people and nations under their rules’ ambit. Both processes have caused a progressive standardization of goods, services, and procedures.
Nearly everywhere in the world, for example, national economic systems, including central banks, ministries of finance, and the like, now have similar designs. Financial instruments like types of stocks, bonds, and their derivatives are similar nearly everywhere, too, as are core industrial processes, antibiotics, germplasm for essential crops and livestock, fast food restaurants, clothing, language of commerce, consumerist notions of the good life, and even blockbuster movies. For some kinds of goods and services — those that become more useful as more people use them (exhibiting what economists call “positive network externalities”) — standardization can be self-reinforcing, leading to market domination by a few products and producers. All over the planet, for instance, people choose from a handful of social media platforms and among basically two operating systems for both desktop computers (including laptops) and tablets.
And, sure enough, this diversity decline is combining with hyperconnectivity to produce cascading failures when key systems are hit by sudden shock. The pandemic snarled just-in-time supply chains of standardized goods that stretched worldwide, catalyzing global inflation. Ransomware attacks exploiting standardized software now regularly cause ramifying damage to vital services, including health and energy infrastructure. Sometime in the not-distant future, extreme weather will likely hit multiple breadbaskets simultaneously, leading to disruption in the worldwide trade of standardized grains that provides a large fraction of humanity’s calories.
The way forward
But this isn’t a counsel of despair. There’s much we can do to defuse the polycrisis. Most obviously, given that Earth’s worsening energy imbalance seems to be emerging as the single most powerful driver of crises across multiple ecological, economic, and social systems, humanity needs to cut greenhouse gas emissions to near zero as fast as possible. Realistically, though, we won’t cut them deeply enough soon enough to keep the imbalance from having devastating impacts, not least on the world’s food supply. So, within the next couple of decades, humanity will almost certainly intervene to increase the atmosphere’s reflectivity to sunlight — perhaps by pumping sulfur dioxide crystals into the stratosphere — until emission cuts really take effect.
For other polycrisis drivers, we can leverage the ways connectivity and homogeneity interact to attenuate their impact, but how we do this will depend on which crises in which systems we’re trying to mitigate. If we want to make pandemics less common and severe, for instance, we can’t do anything about our genetic homogeneity, and our total biomass, at least in the short to medium term, will remain high; we can, however, tweak our physical connectivity when necessary. Travel restrictions should become a regular part of humanity’s response to outbreaks of novel viral diseases. And, yes, despite liberal hand-wringing about the human rights implications of these restrictions, they do work to slow disease spread, by allowing societies to prepare and helping them flatten the infection curve.
When it comes to reducing the incidence and harm of cascading failures in food, technological, and economic systems, we’ll likely find lowering homogeneity more effective, because the world is deeply committed to trade and especially to information connectivity. This could mean targeted interventions — perhaps through tax incentives and regulations — that encourage companies to diversify the world’s food supplies, software ecosystems, and financial instruments.
But the thing we must do most urgently is gain a better understanding of the polycrisis’s underlying mechanisms. Why are so many of the world’s critical systems tipping into negative territory simultaneously? We have only bits and pieces of the answer at the moment, largely because universities, corporations, think tanks, and governments compartmentalize their expertise and attention into categories that align with the systems — economic, health, climate, geopolitical, and the like — that they see in the world. So they tend not to see interactions among these systems that propel the polycrisis, which means they’re far less able to intervene effectively.
Once again, the problem starts at the top: Our societies’ elites, and the institutions they populate and constitute, simply don’t have the cognitive frame to grasp what’s going on. They can improve their grasp, but first they should stop telling themselves that there’s nothing new happening in the world.
