Cities at Risk

David Hulme

Within the next 10–12 years, two thirds of Earth’s population will live in cities. By 2030 there will be more than 40 megacities of 10 or more million around the world. These urban giants will come with grave potential problems including mountains of waste, excessive pollution, food and water insecurity, and ill health. Can humanity survive the 21^st century?

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In this episode of our series on global threats, we’ll look at the problems of urban growth and pandemic disease. Our burgeoning cities are often made environmentally worse by the way we live, and specifically how we dispose of waste.

It’s a problem as old as civilization. The ancient city of Rome built one of world’s first sewage systems. Known as the Cloaca Maxima (which literally means “greatest sewer”), it was begun in the fourth century BCE. This open trench was used to drain the city marshes and later to carry away its effluent. And while it did remove the waste and disease potential, it dumped them into a downstream part of the River Tiber, creating more environmental challenges.

A related modern-day concern has been reported by the BBC in London. In the past few years massive blockages known as fatbergs—composed of cooking oil, lard, grease, wet wipes and sanitary products—have blocked sewers. Flushed down sinks and toilets, it’s a disastrous combination when it hits the cold tunnels and hardens like concrete. One recent fatberg weighed in at 130 metric tonnes; it was the size of 11 double-decker buses and took three weeks to clear. This is a modern problem, which is largely avoidable if we listen and change behavior.

But other aspects of the city are more difficult to resolve. According to the World Bank, cities will produce 6 million tonnes of solid waste per day by 2025, and that number will continue to climb.

In the poorer cities this is often disposed of in open dumps, rife with disease pathogens and at risk of collapse. In Mozambique’s capital of Maputo, a landslide triggered by rainfall at the city dump buried at least 17 people alive and injured others. The trash rises nearly 50 feet above the shacks on its edges and covers more than 40 acres. Mosquitoes breed in the stagnant pools around the 20-year-old dump. Further north in Ethiopia a similar incident last year killed more than a hundred people at Addis Ababa’s dump.

How do we cope with these escalating challenges? Moving more people to the larger cities offers a way of living that many want. And there’s money to be made by investors from crowding people together, even if in the long run it causes many other problems.

Growing cities will require vast amounts of fresh water at unsustainable rates. Faced with severe drought conditions, both Cape Town and Sao Paulo came close to completely running out of water recently. But in Brazil the drought was caused by more than nature’s cycle. Some scientists suspect that deforestation has reduced rainfall, while industrial pollution has fouled the waterways, ineffectiveness slows governmental dam building, and poor maintenance means more water loss.

As time goes by, the big cities of this century will also need more food and other essential resources. Where will these commodities come from in a largely unsustainable world? As the Global Footprint Network put it, “the global effort for sustainability will be won, or lost, in the world’s cities, where 70 to 80 percent of the world’s population is expected to live by 2050.”

Big cities are also at risk from pandemic disease. The megacity is a breeding ground for disease agents of many kinds. With a preponderance of night clubs, schools, theaters, sports clubs and so on, the modern air-conditioned city provides infectious diseases with a perfect environment. For new strains of flu, ebola, zika and drug-resistant tuberculosis, a city with an international airport can serve as a giant incubator. Even hospitals can no longer guarantee that a stay will not result in illness caused by drug-resistant organisms such as streptococcus or golden staph. According to the World Health Organization, current pandemic threats include bird flu, meningitis, SARS, cholera, hepatitis and yellow fever. According to science author Julian Cribb, “every country on earth has experienced at least one epidemic since the year 2000. Some epidemics . . . have had global reach. . . .”

In the wake of the First World War, the Spanish flu infected 500 million, killing 20 to 50 million. Imagine if an equivalent pandemic would break out today, when international travel is so immediate and frequent. And as if our known threats were not sufficient, the World Health Organization has just announced an alert for what they call Disease X. This is to warn us to be aware of the arrival of something we haven’t seen before. It could be the result of a pathogen jumping from animal to human like the AIDS virus, once known as SIV, a disease found in monkeys—or a man-made pathogen, the result of gene-editing released accidentally or used as a weapon.

With all of these terrifying threats before us, it’s important to understand that there will be a solution. Will we survive the 21^st century? If left to human devices alone, probably not.