This plague will not be the last. This is not a prophecy. It is a scientific certainty. So long as the city-sprawl keeps on crushing up against the forest’s edge, so long as extractive industry treads farther into the hotbeds of contagion that are the deepest wilds, so long as highways and airlines, supply chains and shipping routes link those hotbeds to more and more remote corners of the human-inhabited world — in short, so long as things go on as usual, there will be more disease, disruption, and death. What’s more, it will all strike with greater and less manageable frequency. There is little indication that medicine will be able to keep up. Barring nuclear annihilation or Earth-swallowing war, we’ll simply have to learn to live and die on a planet not only blistering with heat but festering with pestilence. So don’t be too quick to let go of that mask. The only alternative is to perish.

The only alternative, that is, apart from a complete re-examination of the socioeconomic paradigm that has given rise to this state of affairs. But don’t get your hopes up. This is precisely what is called for in the case of the climate, and so far, it has proved too tall a task even (or rather especially) for some of the most formidable concentrations of power and resources humanity has yet known. This is no coincidence. The kinds of ventures driving up the likelihood of further and fiercer pandemics are the very same that are pushing us nearer the cliff’s edge of environmental catastrophe. These are twin crises, in other words, with a common origin. They both spill forth from the same polluted spring, which we’ve been drinking from greedily for decades.

First things first. Is a plague-ridden planet so unusual? After all, outbreaks of infectious disease are an age-old phenomenon. Everybody knows about the Black Death, for instance, and anyone who has read a sampling of nineteenth-century fiction will be familiar with the griminess of cholera and the morbid glamour of “consumption.” Bacteria causing the latter, otherwise known as tuberculosis (TB), have in fact been found in the bodies of Egyptians mummified as far back as 4,400 years ago. In later years, smallpox and other contagions made their way across the Atlantic stowed away in the carcasses of European colonisers, wiping out up to 90 percent of the Americas’ Indigenous population upon arrival. Smallpox was also the infection that spurred the development, in the late eighteenth century, of the first vaccine (a word deriving from variolae vaccinae, or cowpox, controlled exposure to which was found to give immunity to the other pox). More recently, the Spanish flu of 1918 infected a third of all humanity, taking three times as many lives as the First World War and doing the job in half the time. Death by disease, as history shows, is a well-practiced and timeworn tradition.

For a time, however, it seemed this tradition might fade into disuse. The twentieth century saw life-saving leaps forward in hygiene, nutrition, and medicine. Following the discovery of penicillin in 1928, the development of antibiotics alone may have spared hundreds of millions a grisly demise by way of infection. Meanwhile, vaccination campaigns led to the eradication of smallpox, the near-eradication of polio, and the suppression of countless deadly illnesses besides. Sanitation and other public-health measures did their part, altogether bringing about a dramatic stretching of the average human lifespan. In rich countries, at least, the declining proportion of deaths due to spreadable sickness spurred talk of an “epidemiological transition”: the dawning of an era in which more people succumb to non-communicable diseases (diseases of old age and bad habit) than to communicable ones. Soon enough, as Adam Tooze sums it up in Shutdown: How Covid Shook the World’s Economy, catching a bug “would be consigned to the past.” To many expectant minds, contagiousness itself appeared poised to fall before the forward march of progress.

Yet this proved much too bright a forecast, and not just because it failed to account for most of the world beyond the wealthy North. Even as the promise of an epidemiological transition was catching on, new forms of biological violence were brewing in the depths of the jungle. Ebola may not actually liquify the insides of the infected, as luridly imagined by Richard Preston in his sensational bestseller The Hot Zone. But as a “haemorrhagic fever virus,” it can involve more than a bit of internal bleeding. First pinpointed in 1976, Ebola has been known to claim upwards of 50 percent (and as high as 90 percent) of its victims — though at about 15,000 they are relatively few. Human immunodeficiency virus (HIV), which causes AIDS, is on another scale altogether. Since its identification in 1981, the defence-eroding pathogen has claimed more than 36 million lives, 680,000 of them in 2020. Some 38 million live with HIV today.

Though each chilling to contemplate, Ebola and HIV/AIDS are merely two swells at the front of a gathering storm. “Emerging infectious diseases” (fast-spreading, never-before-seen ailments as well as known ones popping up farther and farther afield) and “re-emerging infectious diseases” (those coming back from the brink) are among the biggest threats currently looming over our species. As many as three quarters of both emerging and re-emerging diseases owe their rise to incidents of “zoonotic spillover,” or the transference of pathogens from animals to humans. In fact, those able to make the beast-to-biped leap, called “zoonoses,” account for some 60 percent of all contagions ever to have infested humankind. Ebola is one. HIV is another. Further examples include bubonic plague, anthrax, rabies, typhus, cholera, influenza, SARS, MERS, West Nile, Zika — and yes, Covid-19. An epidemiological reading of history since the Second World War suggests that plagues of this kind are only cropping up thicker and faster. Before long, they may also start getting nastier.

Yet what, exactly, are we humans doing to bring all this about? “Make no mistake,” David Quammen writes in Spillover: Animal Infections and the Next Human Pandemic, published all the way back in 2012, “they are connected, these disease outbreaks coming one after another.” They are no flukes, no acts of God. Instead, they are better described as a retaliatory consequence of how we treat the Earth — a planetary immune response, if you will. “Human-caused ecological pressures and disruptions,” the manifestations of a reckless contempt for nature, are rousing deadly forces out of a deep-woods slumber. “Shake a tree,” that is, “and things fall out.”

Shake many trees and an avalanche of vile things might rain down on your head, piñata-style. Deforestation (in the name of resource extraction, industrial farming, urban expansion, and the build-up of infrastructure) is a sure sign of capitalist investment, largely at the hands of modern-day colonial enterprises headquartered in the Global North and their collaborationist counterparts in the South. It is also a confirmed cause of spillover. Look no further than the rapidly denuded regions near the equator. Every year, an area of land roughly the size of Portugal succumbs to deforestation — 95 percent of it in the tropics, where thick seams of minerals, vast virginal woods, and ballooning conurbations can all be found in abundance. (The replacement of forest with beef-cattle pasture alone accounts for over 40 percent of tropical tree-razing, the bulk of it in Brazil.) In addition to a cornucopia of plunderable stuff, the equatorial zone boasts the greatest fount of biodiversity on the planet. Not unrelatedly, it’s also a matchless breeding ground for pathogens.

You don’t have to be a virologist to grasp how, in trampling towards the heart of the jungle where illnesses thrive and multiply, humans might shake loose a scourge or two. Consider the following scenario. A blameless cattle farmer, with the help of generous taxpayer-funded subsidies, claims a small patch of the Amazon for himself. He promptly begins the work of clearing the web of native trees and undergrowth, making room for his herd to graze. (Naturally, his stock is hopped up on a stiff cocktail of antibiotics, adding antimicrobial resistance to the list of potential causes of spillover.) Meanwhile a species of bat, displaced by the incursion, perches in the canopy bordering the farmer’s new plot. Due to their uniquely hospitable physiology, bats are what are called “reservoir species,” or disease carriers usually unharmed by their infectious cargo. But the stress caused by the destruction of its habitat has weakened the bat’s immune system, increasing the load of pathogens in its bodily fluids. A bat then drops its dung into the pasture, shedding a slurry of virulent waste precisely where the cattle feed. Having munched on contaminated fodder, the cattle get sick and serve as “amplifier hosts,” propagating an infection cast off by the reservoir species. After tending to the sickened herd, a farmhand goes home and passes it on to his friends and family. One of them, unwittingly harbouring the bug, travels to a nearby village for supplies, or sets off for a faraway jobsite, or boards a plane to visit relatives abroad. Out there, in the wider world, billions of warm bodies await.

In pretty much this way, globalized networks of production, trade, and travel — instruments for shuttling Southern spoils to Northern markets — virtually ensure the far-flung circulation of a sufficiently contagious zoonotic disease. These systems can and do act as waiting vehicles for the instigation of epidemics — or, as in the now-familiar worst-case scenario, global pandemics. The speed of a given plague’s spread is limited only by its natural infectiousness and by our own capacities to detect and stop it. As recent events have shown, it would be wise not to put too much stock in the latter.

Now, if you compare the drivers of climate change with the catalysts of spillover, it becomes clear they are far from distinct. They are one and the same. Despite surface appearances, neither extreme weather events nor world-stopping pandemics should be counted as sudden, one-off shocks. Both can be traced to underlying trends that are accelerating in terms of severity and scale. Both arise out of a way of life, and out of an economic system designed to maintain it, making not just gorillas and polar bears but ourselves vulnerable to extinction. The threat of both, too, could be seen coming from some way off: no one can say the science didn’t try to warn us, the powers that be least of all. So here we are, caught in what appears to be a permanent battle waged on at least two simultaneous fronts — fronts that threaten to merge and engulf us all, starting with the least culpable. As Andreas Malm quotes of a concerned virologist in Corona, Climate, Chronic Emergency: War Communism in the Twenty-First Century, “we are in an era now of chronic emergency.”

It’s a bleak assessment. What, if anything, can be done to correct it? Nothing less than a total overhaul of the mass-industrial system of extraction and exploitation, production and plunder that makes up modern economic life. There’s simply no hope to be found in any approach relying on the invention of ever-more sophisticated technologies and medicines and other band-aids. We can’t beat nature at that kind of arms race for long, not while the root causes remain unaddressed. Though it may seem utopian to call for a radical re-evaluation of so entrenched a paradigm, such a call, as Andreas Malm puts it, is “exactly as utopian as survival.” We can’t afford to spend another day pretending otherwise. The earth beneath our feet is in revolt. The sky is clogged, the rivers are choking. The supply of food is becoming less and less reliable, and our politics that much more volatile. Our continuing retreat from the restorative fullness of nature into dim caverns of solitude can’t have nothing to do with the epidemic of mental illness tearing through the minds of the young, who face a daunting future to boot. Without mending our relationship to nature, to the living matrix of which we ourselves are an inseparable part, we will destroy the very thing that gives us life. We will be left to survive on the burnt remains of a charred planet, though for how long is anyone’s guess. Yet this is but the end of one path. We can still find it within ourselves to forge others. To do so, we must learn to overcome what Rosa Luxemburg called “a pestilential breath.” It is the smoggy sky as much as the contagious air. It is the poison in our water and in our minds. It isn’t some faraway, abstract thing. In the end, it is us.