There is the obvious and then there is what should be obvious. The obvious is that the coronavirus pandemic has brought much of the human world to a standstill. Many countries are in lockdown. So far, more than 1.7 million have been infected, more than 100,000 have died, and billions live in fear that the numbers of sick and dead will rise exponentially. Economies are in recession, with all the hardship that entails for human well-being.

What should be obvious, but may not be to many, is that none of this should come as a surprise. That there would be another pandemic was entirely predictable, even though the precise timing of its emergence and the shape of its trajectory were not. And there is an important sense in which the pandemic is of our own making as humans. A pandemic may seem like an entirely natural disaster, but it is often — perhaps even usually — not.

The coronavirus arose in animals and jumped the species barrier to humans and then spread with human-to-human transmission. This is a common phenomenon. Most — and some believe all — infectious diseases are of this type (zoonotic). That in itself does not put them within the realm of human responsibility. However, many zoonotic diseases arise because of the ways in which humans treat animals. The “wet” markets of China are a prime example. They are the likely source not only of Covid-19 but also of Severe Acute Respiratory Syndrome (SARS) and some outbreaks of avian influenza, for example. (Another possible source of the coronavirus that causes Covid-19 may be one of the many mixed wildlife-livestock farms in China, but humans are responsible for those, too.)

The “wet” markets, which are found not only in China but also in some other East Asian countries, have a number of features that makes them especially conducive to spawning infectious zoonotic diseases. Live animals are housed in extremely cramped conditions until they are slaughtered in the market for those who have purchased them. In these conditions, infections are easily transmitted from one animal to another. Because new animals are regularly being brought to market, a disease can be spread through a chain of infection from one animal to others that arrive in the market much later. The proximity to humans, coupled with the flood of blood, excrement and other bodily fluids and parts, all facilitate the infection of humans. Once transmission from human to human occurs, an epidemic is the expected outcome, unless the problem is quickly contained. Global air travel can convert epidemic to pandemic within weeks or months — exactly as it did with the coronavirus.