In our mind’s eye, the grey, cratered landscape of the moon is untouched. Up there, still, are the iconic first human footprints, the American flag, and a plaque that reads, “Here men from the planet Earth first set foot upon the moon, July 1969, A.D. We came in peace for all mankind.”

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After five decades on the moon, however, the flag has begun to surrender to the elements. Bleached by harsh UV rays from the sun, the stars and stripes have disappeared, and the nylon has faded to white. But the Americans didn’t just plant one flag on the moon; they planted six. And space travellers have left a much heavier footprint than simple human tread marks. Littering the lunar surface are 181,000 kilograms of forgotten trash.

According to NASA, along with ninety-six bags of urine and vomit, there are old boots, towels, backpacks, and wet wipes. With no garbage cans at hand, the astronauts also littered the landing site with magazines, cameras, blankets, shovels. And, after several international missions, there are now seventy spacecraft on the surface, including crashed orbiters and rovers.

Compared to Earth, the moon has a very thin atmosphere, so it will take some time for the evidence of our visits to erode and disappear. Arizona State University scientist Mark Robinson suggests that with the impact of particle-sized micrometeorites hitting the garbage, the evidence of our brief stays on moon will break down and be gone in about 10 to 100 million years.

Viewed from the lunar surface, our own planet rises above the horizon and shines into the night like a blue moon. From a distance, it, too, looks pristine, but up close, you would see a gleaming cloud of space junk orbiting Earth. Our planet has come to resemble Pig-Pen from the Peanuts comic strip. Right now, there’s almost 3,000 tonnes of space junk continuously circling us.

This wasn’t always the case, of course. In the 1950s, Earth’s orbit was junk free. It was not until March 17, 1958, that it acquired a permanent resident. Today, this dead satellite, the Vanguard 1, holds the title of the oldest piece of orbital debris. It completes a full revolution around Earth every 132.7 minutes. But it is no longer alone. It’s been joined by more than 29,000 other pieces of space junk invisibly circling us, along with over 1,700 active satellites. The US Air Force has been tracking orbital debris, which is mostly made up of spent rocket stages and decommissioned satellites, and keeps a record of any object larger than a baseball. Parts do break loose that are smaller. Everything from paint chips, nuts, bolts, bits of foil, and lens caps are among the 670,000 objects that are one to ten centimetres in size.

As the size of the objects decreases, the number of them increases. For debris that ranges from a millimetre to a centimetre in size, the number is approximately 170 million. But just because they are small doesn’t mean they are harmless. According to the European Space Agency, a one-centimetre object moving at orbital speed could penetrate the International Space Station’s shields or disable a spacecraft. The impact would have the energy equivalent of an exploding hand grenade.

But we don’t dump our spacecraft only in space. We also dump them in the sea. In the Pacific Ocean, miles under the waves, is a site called Point Nemo, which serves as a spacecraft cemetery. Chosen for its remoteness (the closest land mass is nearly 2,400 kilometres away), it is where international space agencies discard large space objects that don’t burn up in the atmosphere upon reentry. From 1971 to 2016, over 260 spacecraft were dumped at Point Nemo. The junkyard became the final destination for 140 Russian resupply vehicles, a SpaceX rocket, the Soviet-era Mir space station, and several of the European Space Agency’s cargo ships, all of which lie on the ocean floor, slowly disintegrating.

At launch, we marvel at these multi-billion-dollar technological masterpieces, but once they’ve outlived their use, like all objects, no matter how advanced or expensive, they become garbage. Humans are a tool-making species, but as a consequence, we are also a trash-making species. And, while we don’t have a love-hate relationship with our things, we do have a “love-indifference” relationship with them. We covet objects before we own them and later throw them away without thinking about them again. That’s the thing about our garbage: we have become experts at acting like it doesn’t exist. Space trash, in fact, barely registers as a blip compared to the enormity of the waste our species generates. In disused home appliances, computers, mobile phones, and other electronic equipment, or e-waste, we generate close to 45 million tonnes of waste every single year. That’s the equivalent of over 4,500 Eiffel Towers. Trash that could obstruct a city skyline. But not only do we not see it, most of us don’t even know where it goes.

There are some things we do know about our trash. The world leader in trash production, for instance, is the United States. Around the world, rich countries and rich people produce more garbage. Individually, each American throws out about 3.2 kilograms of garbage a day, or over ninety tonnes of garbage in a lifetime. As Edward Humes writes in Garbology, “A single person’s 102-ton trash legacy will require the equivalent of 1,100 graves. Much of that refuse will outlast any grave marker, pharaoh’s pyramid or modern skyscraper.”

But, even then, what we toss out is just the tip of the proverbial trashberg. Most garbage comes from the manufacturing process. What we throw in the bin—the final product—represents a mere 5 percent of the raw materials from the manufacturing, packaging, and transportation processes. Put another way, for every 150 kilograms of product we see on the shelves, behind the scenes, there’s another 3,000 kilograms of waste that we don’t see. In total, the world produces approximately 3 million tonnes of garbage every twenty-four hours. That number is expected to double by 2025. And, if business continues as usual, by the end of the century, it will be an unfathomable 10 million tonnes of solid waste a day.

It isn’t just our factories that create waste. As biological beings, we generate our own waste as well. And, with 7.5 billion people on the planet, that crap adds up. In The Origin of Feces, David Waltner-Toews charts the meteoric rise of human excrement: “In 10,000 BCE there were about a million people on the planet. That’s 55 million kilograms of human excrement scattered around the globe in small piles, slowly feeding the grass and fruit trees….By 2013, with more than 7 billion people on Earth, the total human output was close to 400 million metric tons (400 billion kilograms) of shit per year.” With such colossal amounts of human biological waste and manufactured solid waste, it’s like a magic trick of epic proportions that it all just seems to—poof—disappear.

Before the days of the garbage collector, though, people had to deal with their shit, literally. There was no getting away from it, because it sat, steaming, fly ridden, and reeking right in front of us. The familiar Brooklyn stoop we all know from Sesame Street is not just an architectural carry-over from the Dutch, it was also a way of dealing with nineteenth-century waste. The steps lead up to the parlour floor because, at the time in New York, people threw their garbage out of the windows and right on to the city streets. The trash was so high—up to a metre in the winter when it combined with snow and horse waste (the latter of which piled up at a rate of 1,000 tonnes of manure and 227,000 litres of urine every day)—that the stoop allowed people to get up above the mess and make their way safely in the front door.

Nineteenth-century waste management was assisted by scavenging dogs, rats, and roaches, but the primary street cleaners were pigs. In the United States, piggeries were specifically erected for big towns with populations of over 10,000. Our trash was their dinner, with an average of one tonne of waste digested by seventy-five pigs a day. It’s not uncommon to find paintings of New York City at the time featuring these roaming pigs. For the Europeans who painted them, the urban swine were a novelty, but for New Yorkers, the fact that hogs ran wild in the streets was pretty much standard fare.

Up until the 1840s, thousands of pigs roamed around Wall Street. Today, the area is known for its bankers and high rollers, but the name Wall Street, from the original Dutch “de Waal Straat,” derives from a 3.5-metre fence built to keep hogs from causing damage to the streets and residents’ gardens.

In Paris, trash and human waste also flooded city streets. The French were the first to establish a corps of sanitation workers and had begun managing city waste in this manner four centuries earlier. But streetside filth was a continual problem. Instead of putting it out in the streets, Parisians were ordered to build cesspools in their backyards. Inevitably, the neighbourhood stench, along with bouts of cholera, became far too much to bear. The French switched over to a method the Chinese had been using for thousands of years: managing their population’s waste by turning it into “night soil,” a euphemism for human excrement used as manure for farming.

By the 1800s, what growing cities had discovered was that a city, by its very nature, localizes and concentrates waste on a massive scale. They become, for lack of a better term, engines for producing giant shit heaps. The Chinese had been diffusing the situation by taking their excrement from populous areas and returning it to the countryside. There, it wasn’t waste. It was brown gold. Human manure was returned to the soil in order to feed the nation. The system, in fact, worked very well, and until recently, China was renowned for its fertile soil and sustainable agriculture. For thousands of years, about 90 percent of human manure was recycled in China and accounted for a third of the country’s fertilizer.

Consider for a moment your own digestive contribution. On average, you excrete about fifty to fifty-five kilograms of feces and about 500 litres of urine a year. But this “waste” contains valuable nutrients. According to the German Corporation for International Cooperation, on an annual basis, that works out to about “10kg of nitrogen, phosphorus and potassium compounds, the three main nutrients plants need to grow—and, helpfully, in roughly the right proportions.” One person’s excrement is enough to fertilize and grow over 200 kilograms of cereals a year.

The Japanese also recognized the value of shit. During the Edo period (1603 to 1868), in the area that is now Tokyo, the Japanese ran a closed-loop system, and shimogoe (translated as “fertilizer from the bottom of a person”) became critical for sustainable agriculture. On roadsides near the fields, buckets were provided for travellers, who were encouraged to leave their waste behind. As David Waltner-Toews writes, “The seventeenth-century city of Edo sent boatloads of vegetables and other farm produce to Osaka to be exchanged for the city’s human excrement. As the cities and markets grew (Edo had a million people by 1721) and as intensive paddy-farming increased, prices of fertilizers, including night soil, rose dramatically; by the mid-eighteenth century, the shit owners wanted silver—not just vegetables—for payment.”

Crap had become a high-priced commodity. Landlords could increase the rent they charged if the number of tenants dropped in their building, because with fewer defecators to pad an owner’s income, running the property became less profitable. As a business, managed through private agents and not the government, shimogoe prices were set by the landlords, leading to conflict with farmers, who were often gouged with high prices.

There was also good shit and bad shit. Rich shit surely stank as much, but it was more highly prized. As the rich ate more diverse diets, this resulted, according to the farmers, in better nutrients in their feces. As for its value, the price of shimogoe depended on demand, but at its height, it rose up to 145 mon per household. For perspective, in 1805, 100 copper mon could buy a good lunch of mushrooms, pickles, rice, and soup. By the 1800s, the price of human waste was so valuable that stealing it became a criminal act that could result in imprisonment.

But for those steeped in the fine art of stercoration, there was one type of excrement that was always top of the list. When it came to the best fertilizer in the world, there no competing with guano.

People have gone to war over many things in history, but the guano war of 1864 to 1866 may have been the first time a war began over the sovereignty of bird shit. The guano was a virtual gold mine for Peru. Spain knew this and was determined to reassert its power and seize the guano from its former colony. As a result, Chile joined the two-year war, and the South American countries fought together to fend off their former colonizer.

Coming in by boat, you smell the Chincha Islands long before you see them. With nesting colonies of pelicans, boobies, and cormorants, the Peruvian archipelago was home to over a million birds. Each bird produced about twenty precious grams of droppings a day, together producing around 11,000 tonnes per year. Over generations, and with little rainfall in the area, the mounds grew into mountains. And, by the early 1800s, the guano on the Chincha Islands was over ten storeys tall.

Guano’s property as a powerful fertilizer had been known to the locals for centuries; they called it huanu. Seabird excrement is particularly potent because it’s packed with marine nitrogen. As the birds feed on huge schools of anchoveta and plankton, they act as “biological pumps” that transfer the nitrogen into terrestrial ecosystems. This gift of soil fertility was so highly valued that, for the Incas, killing a seabird could result in a death sentence.

The Europeans came to realize its value when explorer Alexander von Humboldt first brought some back with him in 1804. For the farmers using it on their land for the first time, the results seemed miraculous. Exhausted soils suddenly became fertile again, and it boosted crop yields by 30 percent. Unlike regular barnyard manure, guano was special shit: according to one expert, it was thirty-five times more powerful.

By 1850, as science writer Thomas Hager notes, the Chinchas— these barren islands covered in bird shit—were “acre for acre…the most valuable real estate on earth.” A “guano mania” had taken hold. Tens of thousands of tonnes of guano were exported every year, accounting for up to 60 percent of the Peruvian economy. The Americans, eager to secure their own sources of guano, passed the Guano Islands Act on August 18, 1856, essentially allowing the United States to lay claim to any island it found with guano deposits. To date, over a hundred islands in the Pacific and Caribbean have been claimed, and while most titles were relinquished after the guano was exhausted, the act is still in effect today.

Eventually, that became the problem with the Chinchas. The guano was a finite resource that could not be replenished as quickly as it was extracted. By the time of the guano war (which Spain lost to the united front of Chile and Peru), there was less than a decade’s worth of guano left. When it was gone, Peru went bankrupt.

One man saw the disaster looming and realized that Europe would soon be in very deep shit, figuratively speaking. With the primary guano source depleted, the fertilizer business had moved on to Chilean nitrates, a white granular substance found in the desert that was the next best thing. But William Crookes, an English scientist, had run the calculations. By his estimate, at the current rate of demand, even the nitrates would be gone within decades. In his presidential address before the British Association for the Advancement of Science in 1898, the esteemed chemist sent out the clarion call before a packed house: “England and all civilised nations stand in deadly peril of not having enough to eat. As mouths multiply, food resources dwindle….I hope to point a way out of the colossal dilemma. It is the chemist who must come to the rescue of the threatened communities.”

What Crookes was urgently calling for was the development of synthetic manure. But, despite his prophetic remarks, the world had no way of knowing that this fertilizer would literally come from thin air.

The Haber-Bosch process has been called the greatest invention no one has ever heard of. Named after Fritz Haber, the scientist who invented it, and Carl Bosch, the engineer who industrialized it, the invention promised the world unlimited fertilizer. Finally, a source had been found that would not run out, because atmospheric nitrogen was everywhere.

Today, factories all around the world use the Haber-Bosch process to make synthetic nitrogen fertilizer. In 2016, they produced 146 million tonnes. As the human population grows, the demand rises. In fact, the production of synthetic nitrogen and the rise in population are intimately linked. If you’ve ever wondered how the human population jumped in a single century from 1.6 billion people in 1900 to over 7.6 billion today, it is because we no longer use manure to grow food. This form of fixed nitrogen, in combination with the development of pesticides and new crop varieties, brought in what’s known as the green revolution. Humans had tamed the earth, and their numbers exploded as a result. Every year, 83 million people are added to the population of the planet. More people means more waste. And, since the development of the Haber-Bosch process, a scandalous proportion of that waste has been uneaten food.

The United States produced more than 31 million tonnes of food waste in 2010. According to the United States Environmental Protection Agency, by weight, that is ten times more food waste than e-waste that year. All of the energy used to grow, ship, and sell food that is ultimately tossed away is also wasted. In the United States, in greenhouse emissions alone, it works out to all of the offshore oil-and-gas reserves being drilled for nothing. On a global scale, according to the UN’s Food and Agriculture Organization, approximately one-third of human food production does not get eaten. That is a jaw-dropping 1.3 billion tonnes of food that gets thrown out every year.

On top of that, there’s another aspect to food waste. And it takes the form of the synthetic fertilizer made by the Haber-Bosch process. We use an enormous amount of fertilizer: for every person on the planet, there’s approximately twenty kilograms of ammonia spread annually onto the fields. But a mere 15 percent of that manufactured nitrogen makes it into our mouths in the form of food; the vast majority of our chemical fertilizers dissolve into waste.

As rains fall over the land each spring, nitrogen and phosphorus compounds from fertilizers are carried off into streams, rivers, and lakes and eventually drain into the ocean. Here, the mixture of nutrients from our fertilizer runoff and sewage sparks an algal feeding frenzy, causing algae to spread over tens or even hundreds of square kilometres.

Inadvertently, we are fertilizing the ocean. The resultant “bloom,” however, is deadly. Marine plants and animals living beneath the thick, slimy mat of algae are deprived of sunlight. And, when the algae overgrowth dies and sinks to the ocean floor, the massive decomposition process robs huge amounts of oxygen from the water, making it impossible for marine life to breathe. Those species that can’t move to another location will not survive, and the biological desert that’s left is known as a dead zone.

There are over 500 of these dead zones in the oceans, and they are growing bigger. The fertilizer that was supposed to make life flourish is turning coastlines into graveyards. By disrupting the balance of nature with our human-made systems of survival, we have created a vicious cycle: now we need more fossil-fuel energy (the equivalent of about 2.5 tonnes of TNT per acre) to create more food, in turn creating more mouths to feed. And, every year, the cycle escalates.

The Haber-Bosch process alone uses up almost 2 percent of the world’s energy supply. And for every tonne of ammonia created, two tonnes of carbon dioxide are released into the atmosphere. We are blind to this nitrogen waste in the ocean, just as we are blind to the carbon dioxide waste we can’t see. But there is one form of waste we can see when it gets out of hand: air pollution.

In Beijing, a new colour was named by the general public in November 2014. It was called “APEC blue.” It was the result of a mission that began months earlier, when the Chinese central government tasked 434,000 staff in the regions of Beijing, Shandong, Tianjin, Shanxi, Hebei, Inner Mongolia, and Henan with orders to execute a grand plan. The teams had one ambitious goal: to change the colour of the sky.

In the days leading up to the arrival of international delegates for that year’s Asia-Pacific Economic Cooperation (APEC) summit, 11.4 million vehicles were ordered off the roads, and over 10,000 industrial plants suspended production. Under strict supervision, close to 40,000 other factories were put on a rolling schedule to limit their working hours and consequently the smoke and exhaust fumes they normally emitted.

The plan worked spectacularly. For two weeks in November, Beijing’s notoriously thick grey-brown fog cleared, and the air pollution fell by a jaw-dropping 80 percent. In its place, ready to welcome foreign dignitaries, leaders, and the world press, were soft white clouds and a brilliant APEC blue sky. But soon after the summit ended, the blue was gone too.

In polluted cities, the term “AQI” is as familiar to anyone as “celsius” or “fahrenheit” is. It stands for air-quality index, a scale designed to go from zero to 500. Just by looking at the degree of haze, experienced residents can calculate the air quality. If you see a bit of haze on the horizon, that’s 100. By 200, the grey horizon has closed in on you. At 300, the pollution haze is blocking the sun.

An AQI of 300 and above is considered hazardous to human health. Health effects include “serious aggravation of heart or lung disease and premature mortality in persons with cardio-pulmonary disease and the elderly; serious risk of respiratory effects in the general population.” Off the charts, at over 700, the air is described as industrial smoke. It’s so thick that it’s “chemical-tasting, eye watering.” Coupled with a sandstorm, on May 4, 2017, the air in Beijingwas literally breathtaking. With an AQI of 905, Beijing had gone three times past the hazardous limit.

On bad days, let alone severe days, spending even twenty minutes outside can leave people feeling sick. Sore throats and coughs without cold or flu symptoms have become common. And, for residents, especially those who live and work near factories, the coughs do not seem to go away.

The face masks worn by the Chinese public are now iconic. But, in Beijing, only one section of society has it relatively easy when the pollution gets out of control. The rich can afford to protect their well-being by insulating themselves from the choking skies.

In the capital, the wealthy can send their kids to private schools, many of which have giant “playground bubbles” for children to play in. These pressurized air domes are equipped with hospital-grade air filters to purify the air and provide perfect “weather” year-round. On days when the AQI requires the children to stay inside, they are kept safe behind air-locked doors.

This pollution proofing doesn’t come cheap. Air domes cost millions of dollars, and even at home, it costs tens of thousands of dollars to maintain fresh pockets of air for families to breathe in. Apartments in luxury high rises are equipped with the latest high-tech air and water purifiers to provide a semblance of normalcy.

The poor have no option but to breathe the bad air around them. And it’s not just China: India is home to eleven out of the twelve worst polluted cities. Likewise, Saudi Arabia and Iran have cities with pollution levels that make them hazardous to live in. According to the World Health Organization (WHO), which monitors a database of 3,000 cities in 103 countries, over 98 percent of cities in low- and middle-income countries failed to meet WHO air quality guidelines, whereas in high-income countries, the failure rate nearly halved to 56 percent.

Of course, our bodies have inbuilt biological air filters—our lungs—and examining them can reveal the particulate matter we absorb from the outdoors. Pathologist Paulo Saldiva, who serves as a member of the scientific committee of Harvard University’s school of public health and as a member of the air-quality committee of the WHO, has done autopsies on the lungs of people exposed to outdoor air pollution. Blackened and pockmarked with carbon, they could easily be mistaken for the charred lungs of a cigarette smoker.

Every day, we inhale about 23,000 breaths, taking in, on average, 12,000 litres of air. The tiny hairs in our noses and the cilia that protect our lungs filter out the larger particles, but the most dangerous particles are the small ones, called PM2.5, because the particulate matter is less than 2.5 micrometres. Collectively, they are the invisible sandstorm of sulphate, nitrates, black carbon, mineral dust, sodium chloride, and ammonia that we call “pollution.”

Originating from the exhaust of car engines, mines, power plants, and industrial boilers, these incinerated particles have been strongly linked to lung cancer, kidney and cardiovascular disease, as well as asthma. In China, already the country with the highest rate of lung cancer, medical experts expect the number of lung-cancer patients to rise to over 800,000 a year by 2020. This is a silent epidemic. Worldwide, the WHO estimates that 3 million people die prematurely from outdoor air pollution every single year. By comparison, the number of people who die from AIDS is about a third that number, or 940,000.

When you sit back to consider it, the pollution we produce on an annual basis is staggering. It includes:

manufactured chemicals; 30 million metric tons a year plastic pollution of oceans; 8 million metric tons a year hazardous waste; 400 million metric tons a year coal, oil, gas; 15 gigatonnes (billion metric tons) a year metals and materials; 75 gigatonnes a year mining and mineral wastes; roughly 200 gigatonnes a year polluted water (mostly contaminated with above wastes); 9 trillion metric tons a year.

These are the ingredients for a massive toxic bomb, according to veteran science journalist Julian Cribb. Globally, we build one of these bombs every single year. The difference is there’s no deafening boom. Instead, it’s a quiet fallout: the invisible particles seep into the food we eat, the water we drink, and the air we breathe. As Cribb writes, “Industrial toxins are now routinely found in newborn babies, in mother’s milk, in the food chain, in domestic drinking water worldwide. They have been detected from the peak of Mt Everest (where the snow is so polluted it doesn’t meet drinking water standards) to the depths of the oceans, from the hearts of our cities to the remotest islands….The mercury found in the fish we eat, and in polar bears in the Arctic, is fallout from the burning of coal and increases every year.”

The idea that there is some sort of “outside” world we can exist independently from is an illusion. Science shows us what our own eyes can’t see: that everything in existence is part of a network, part of a flow. What we put out into the environment will eventually find its way back into our bodies.

Ziya Tong will be speaking at our upcoming event, The Walrus Talks Living Better, on October 29th. RSVP here.

Adapted from The Reality Bubble: Blind Spots, Hidden Truths, and the Dangerous Illusions that Shape Our World by Ziya Tong. Copyright ©2019 Ziya Tong. Published by Allen Lane, an imprint of of Penguin Random House Canada Limited. Reproduced by arrangement with the Publisher. All rights reserved.

Ziya Tong Ziya Tong is the vice chair of WWF Canada and is best known as the longtime co-host of the Discovery Channel's Daily Planet, which she anchored for a decade from 2008-2018. She also served as a correspondent on Nova ScienceNOW alongside Neil deGrasse Tyson.