Thomas Homer-Dixon, the Canadian student of complex systems and author of The Upside of Down, wrote in his 2006 book that “September 11 and Katrina won’t be the last time we walk out of our cities.”

Today, many big-city dwellers appear to be seeking refuge in less crowded towns and rural landscapes. The wealthy, at least, are seeking “bugout” homes away from major cities as places to ride out the pandemic, the economic downturn and the civil unrest that are gripping the world. Beyond news reports, I’ve heard from friends that homes are being snapped up in eastern Washington state and New York’s Hudson Valley by coastal city dwellers looking for a refuge in turbulent times.

It’s not just residents who are leaving. The New York Times reports that retail restaurant and merchandise chains are exiting Manhattan because it is “unsustainable.” New York City no longer teams with tourists, and its office towers are largely empty. That makes for empty streets with few customers for the city’s many retail establishments. This story is being repeated in other major cities including AtlantaChicagoDenverHoustonLos AngelesSeattle, and St. Louis.

In an op-ed appearing in The Globe and Mail, Homer-Dixon explained the underlying structural problems that have opened our global society to increasing risk:

The relatively new science of complex systems shows that such tipping events are made more likely by the unprecedented connectivity in the networks that humanity has laid down in a dense web across Earth’s surface – air traffic, financial, energy, manufacturing, food distribution, shipping and communication networks, to name just a few.

This science also shows that until we manage this connectivity better – which could mean, among other changes, reducing our international travel, simplifying global supply chains and bringing some production processes closer to home – we’re likely to experience more frequent tipping events of ever-higher destructive force.

The idea that we are going to return to the world of 2019 seems increasingly unlikely. That world was highly fragile which is why it shattered in so many pieces with so many casualties when the coronavirus pandemic hit. Returning to that world would mean, in Homer-Dixon’s words, “more frequent tipping events of ever-higher destructive force.” That hardly seems like the destination we should seek.

And yet, everything being done by authorities is with an eye toward returning us to “normal.” Vast of amounts of money have been pumped into the financial markets, so much so that in the United States, at least, they have returned to record highs—even as the global economy remains in possibly the steepest slump in modern memory. Governments have lavished essentially free money on struggling businesses. Individuals have received substantial sums in the form of unemployment benefits.

The premise behind all this unprecedented government and central bank spending is that we are merely in a rough patch. Once we get through it, we can gradually return to normal.

The supposed linchpin of this narrative is a vaccine that will rid us of COVID-19. Even if we find a vaccine that works, we would still face the myriad threats that will likely continue to challenge our stability: vast economic inequality, racial strife, geopolitical tensions, trade wars, climate change, a wildly fragile financial system, and the vast wreckage of the economic downturn which is hallowing out retail districts, the travel and tourism industry and bricks-and-mortar entertainment venues across the planet while leaving huge numbers unemployed.

But an effective vaccine is not a given. And even if one is developed, it may not be 100 percent effective—most vaccines aren’t—and, in all likelihood, it won’t eradicate the virus even if it is.

Perhaps just as important, COVID-19 is unlikely to be the last pandemic we experience. Because of the way we’ve structured our society, other novel pathogens are likely to strike us in the not-to-distant future.

Given all this, the perceived risks of living in the close quarters of major cities may continue to rise. Big cities will not disappear, but they may be far less prosperous than they have been. After all, their very structure is designed for large numbers of people to be tightly packed into the same space, whether a restaurant, an office suite, a concert hall or even a city sidewalk. Rather than the jammed midday big-city sidewalks of 2019, we may have to envision many fewer people giving each other a wide berth as they walk past boarded up storefronts while hurrying between the few businesses that remain open.

That implies a far different world from the one we inhabited at the beginning of the year in practically every aspect of our lives.

Photo: Empty lot by the East River in New York City. Long Island City in the distance. (2019). By Rhododendrites.Via Wikimedia Commons https://commons.m.wikimedia.org/wiki/File:Empty_lot_by_the_East_River_(13566).jpg