Getting through the 21st century without a mass-extinction event means making ourselves far more scarce. At least over large parts of the planet.
The idea is to leave a hefty portion of the planet’s land surface empty of our presence, in a relative sense. Both the European Union and the U.S. under the Biden administration are exploring plans to keep 30% of the land under their jurisdiction in people-free conservation. The “30 by 30” plan—protecting 30% of land by 2030—is now a policy goal in California and elsewhere around the world.
That’s a big increase over the roughly 15% of land-surface area worldwide now protected in various ways, and a significant step toward the 50% proposed by E.O. Wilson in his “Half Earth” plan. Wilson, the preeminent conservation biologist of our time, recommended this proportioning of land use for the sake of the thousands of species now in danger of extinction.
Only about 3% of the animal biomass left on the Earth’s land surface is wild, the other 97% being humans and our food animals. Wilson’s plan, if we were to pursue it, would address this shocking imbalance. It has the additional advantage of efficiently pulling vast amounts of carbon out of the atmosphere.
If that kind of habitation pattern is what we need, then cities will keep doing what they’ve been doing through history, and even more intensively in the last half-century: They will grow. They will become massive. There are at least 33 cities inhabited by more than 10 million people now, according to the United Nations; they’re home to more than 13% of the world’s population. Those numbers are all but certain to increase. Before this decade is done there will be 10 additional megacities. Demographers project that Delhi will have a population exceeding 38 million before 2030, overtaking Tokyo as the top megacity.
Already the UN counts 4.3 billion city dwellers on Earth, with most living in smaller cities whose numbers will swell. The number of cities with at least 500,000 people is set to surge in this decade by 57% in Africa and by 23% in Asia. Civilization will become even more urban: By the meaning of those words, that’s a kind of tautology, but it’s also a survival mechanism.
What we’ll ask of cities in the climate era includes many contradictions, even some double binds. The climate city will need to be compact but with green space. It will have to be energy-efficient but also home to a great deal of industrial production. Instead of being carbon hot spots, belching out emissions, it would be better if cities were carbon-neutral heat sinks, helping to cool the planet. And while a good deal of agriculture and even animal husbandry should take place in cities, to help empty more of the country, our urban spaces should also feel pleasant and parklike for their human inhabitants.
What this means is the creation of a kind of techno-utopia that extends far into the sky, with farming skyscrapers that enlist gravity to help with agricultural recycling of composted animal wastes. It will extend deep underground as well, where freight tunnels will connect factories and robotic vehicles will move things around in ways that don’t disturb our surface life. It will contribute large amounts of electricity to satisfy its own huge need for it.
Many ideas like this are described in The Industrious City, a new architecture and design book that envisions Switzerland as one big agglomeration of cities that turns the entire country into a single functioning complex. The Swiss already plan to build a 500-kilometer tunnel that stretches across most of the country to convey manufactured goods from one city to the next without disturbing surface life.
To see the climate city, look to planning texts from Holland that describe “vertical farms,” which are skyscrapers that include agriculture, aquaculture, chickens, pigs, and recycling of all waste within towers of food production. Hydroponics and vat-based food production using yeast, algae, and even meats will also be integrated into these towers. This kind of concentrated agriculture will free up land for other purposes while reducing the transport costs of goods from where they’re grown to where they get eaten.
Still other projects concern turning the tops of all city structures white, to reflect sunlight back into space, helping to cool the planet. Some of these white surfaces might even be electricity-generating or simply composed of solar panels, creating electricity as well. The white walls and roofs of traditional Mediterranean cultures were an early example of this urban-cooling strategy. As building codes change, so will cities’ albedo.
Talk of “smart cities” is a little bit overblown, part of the AI craze, because the smarts in cities are always going to remain human. But a highly systematized, quantified, and automated coordination of city functions, not just transport but also inputs and outputs of all kinds of supplies and wastes, will help cities achieve the good efficiencies necessary to make them superior in carbon-burn terms.
Even after we transition to carbon neutrality or turn carbon-negative, the multiple levels of coordination necessary for cities to work will benefit from conscious study and design, extensive recording systems, quantification, and, yes, computers. The city will not become a computer, or even much like a computer, but it will use computers. The climate gains from this effort in system coordination will include a reduction in wasted resources, unnecessary transport, and recycling failures.
Ideas from the Victorian era about “garden cities” will remain evergreen, as all this densification and verticalization will still want to result in places humans like to live. Parks can also be suspended at skyscraper level, with the High Line in Manhattan serving as a nice precursor of how that might work. Indeed, in the era of rising sea levels, coastal cities may have to take advantage of the urban tendency to stack levels on levels and shift some of life into the sky.
It’s not just housing, jobs, and a certain percentage of food and electricity production that must be gathered into our megacities. It’s also a chance to do what cities are best at: culture. Gatherings, even crowds. Can we imagine crowds coming back after the pandemic, as part of the technological sublime, the world of urban adrenaline? Yes. It will happen.
Humans are social primates, we crave contact. We might as well be bees in a hive; solitude isn’t good for us. The constant crowd of a city is a rush we like to feel. In the deepest, oldest parts of our brain, a crowd feels like safety, and there is some truth in this.
This is all a heavy burden to put on relatively small areas of land. But cities started civilization, and now they can help save it.
Robinson writes science fiction in Davis, Calif. His latest novel is The Ministry for the Future.
