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Winter 2000
How Cities Green the Planet
Peter W. Huber, Mark P. Mills

Think of the skyscraper as America's great green gift to the planet. It packs more people onto less land, which leaves more wilderness undisturbed in other places, where the people aren't. The city gets Wall Street, Saks, the Met, and the Times Square crowds, which leaves more flyover country for bison and cougars. It's Saul Steinberg'scelebrated New Yorker cover, painted green.

Among all the various metrics of green, land is by far the most important and, in today's debate, the most often overlooked. As traditional conservationists have always recognized, land—broadly defined to include streams, rivers, and coastal waters—is critical, because that's where the wild things are. The less real estate we occupy for economic gain, the more we leave undisturbed as wilderness. And the city, though profligate in its consumption of most everything else, is very frugal with land. The one thing your average New Yorker does not occupy is 40 acres and a mule.

As it grows—or, as the Sierra Club sees it, as it sprawls—a city does indeed seize land. In 1800, Manhattan ended at about City Hall Park; farms and unsettled wilderness occupied everything north of Chambers Street. In 1811, when the Commissioners' Plan laid out the New York City grid, it extended only to 155th Street—the Commissioners not being able to imagine that the city would extend beyond that point "for centuries to come." Even as the twentieth century opened, Vincenzo Bendetto was still farming his family acres at Broadway and 213th Street. Today's seamless Manhattan spread of tarmac, concrete, and high-rise is just yesterday's sprawl come of age.

The sprawling hasn't stopped, around New York or any other major city. Nationwide, cities, suburbs, and local roads cover about 27 million acres, and highways cover as much again. This 54-million-acre total is well over double the area occupied in 1920. Thousands of acres of farmland and forest are developed every day in the environs of cities and towns. One projection foresees 60 megacities in America by 2050, with over 10 million people each—a total of city dwellers that is more than double the population of the entire nation today. These cities, one should then expect, would doubtless cover something like twice their current area.

This is what so alarms the greens, and they're determined to stop it. "This time the enemy isn't the Soviets, but sprawl," declares New Jersey governor Christine Todd Whitman. It's "a virus eating us from the inside out," says the Sierra Club. In January 1999, Vice President Gore proposed a $10 billion program of "Better America Bonds" to help cities contain themselves. The idea is to halt the city's organic growth with collars of development-free green. And by containing the city we will . . . well, what exactly will we achieve?

Just the opposite of what the sprawl police suppose. Collaring the city will culminate in less wilderness, not more. The natural growth of the city is the best thing going for the wilderness. The rise and spread of the metropolis has brought about a magnificent renaissance of green.

Sure, our cities are big, but the country is a lot bigger. Cities, suburbs, roads, and all the highways cover under 3 percent—yes, only 3 percent—of the 2 billion acres of land that constitute the lower 48 states. If that percentage seems implausibly low, it's because our casual impressions are so biased. Some 80 percent of us live in the cities or their immediate suburbs, and we spend almost all our time there.

That's today. In 1790, the demographics were reversed: the U.S. population was 80 percent rural. What brought about such a remarkable shift? Technology, mainly: relentless improvements in agricultural productivity have enabled us to feed more Americans and more of the rest of the world, too, using less land. The farmers stopped farming; their children moved to the city.

The city has had a second, equally powerful environmental impact: it has lowered fecundity. Cities grow not because the people living in them have a lot of children, but because the people in the country do. Absent continuous immigration, the population of cities would shrink. Population growth in the city represents, in large part, population decline out in the sticks.

People come to the city in search of money; and money, it appears, induces them to have fewer children once they get there. This much is clear: where wealth rises, fertility falls. Rural versus urban figures confirm that fact, so do developed-world versus developing-world statistics, and so do the historical trends. Developed-world fertility has been falling quite steadily for two centuries. In the United States, it dropped from eight children per woman to two.

Parents recognize, it seems, that wealth permits them to raise fewer, more robust, children, and, given the chance, that is what they choose to do. When people get rich enough, lifetime fecundity falls to the point of zero population growth, or below. This takes a while, of course. At first, more resources, more wealth, make possible more life. Richer people live longer. More women grow to adulthood to bear children of their own. Population rises, just as Malthus said it would—with just one critical correction: the lowering of fertility. Wealth concentrates in the city, and it is there that fertility drops the furthest. So far as the wilderness is concerned, the green case for the city can be as simple as that. The city is a population sink. To put it another way, the view from Wall Street is the greenest on earth.

For America as a whole, wealth and city overtook poverty and country sometime around 1920. Until about that time, the effects of immigration, an increasing life span, and a rising demand for food outweighed the effects of rising agricultural productivity and declining fertility. As a result, forests contracted. But around 1920, the balance shifted, and forests began to expand once again.

The upshot has been a truly remarkable, if little noted, environmental reversal: the steady reforestation of the American continent. When Europeans first arrived—after millennia of deforestation by fire, promoted by American Indians—the area now represented by the lower 48 states had about 950 million acres of forest. That area shrank steadily until about 1920, to a low of 600 million acres. It has been rising ever since. Just how fast is hard to pin down: the continent is large, most of the land is privately owned, and definitional debates rage. But all analyses show more, not less, forest land in America. And all agree that roughly 80 million more acres of cropland were harvested 60 years ago than are harvested today. Most of this land is on its way to being reforested, too. At least 10 million acres have been reforested since 1987 alone. Thus, for the first time in history, a Western nation has halted, and is now rapidly reversing, the decline of its woodlands.

Why do so many of us believe just the opposite? We've been spun, that's why. Green activists and their political friends publicize only half of the environmental ledger and play a shell game with definitions. They're engaged in a great green fraud, and a very harmful one, too.

Definitions first. The anti-sprawl activists often count as "developed land" some 90 million acres of farmsteads, field windbreaks, barren land, and marshland. This rural land has nothing to do with any reasonable definition of urban sprawl or even of "development," and to count it as such is to conflate Trump Tower with a stand of poplar trees grown by a farmer as a windbreak. But the activists need these 90 million acres, because if they admitted that cities and their suburbs covered only a tiny 3 percent of the continental U.S., who could take their fear of sprawl seriously? That extra 90 million acres makes it seem as if the "sprawling city" covers 150 million acres, more than double the real number. This begins to sound like quite a lot, though it is still only 8 percent of the 48 contiguous states.

Now, the ledger. Some 25 million acres of land have given way to new development of one kind or another in the past three decades; perhaps half that area was farmland that gave way to suburbs at the periphery of cities. The expansion of the city largely replaced one human use of land—agriculture—with a second—dwellings. Where we used to house corn and cattle, we now house ourselves. No great loss for wilderness there, but that's the half-story we hear about. What we don't hear is that, during exactly the same period, 95 million acres of agricultural land even farther from the city returned to wilderness or began the process of doing so, now that farmers no longer cultivate them. In other words, far more land is being relinquished by agriculture to wilderness than is being converted from agriculture to suburbs. A fair estimate of the net gain for wilderness: some 70 million acres in the last quarter century. The loss of agricultural land to the city has meant a loss in greenish vistas for (mostly wealthier) people living at the periphery of the suburbs but almost no loss of true wilderness. The simultaneous, and much larger, return of agricultural land to wilderness farther out was just that—an enormous gain for the wild.

The city curtails not only its own Malthusian propensities but the country's, too. The city plants no taters or cotton, but it's very good at cultivating two things greener still: capital and knowledge.

For at least a century now, the average American has eaten more food and consumed more energy, even as the American farmer has plowed fewer acres and cut less wood. We accomplished that by learning to live in three dimensions, not just two, taking less from the living surface of the planet and more from its sterile depths. Cement, steel, and synthetic plastics displace hardwoods in our ships, dwellings, and furniture, leaving the wood itself to the forest. Fossil and nuclear fuels displace wood in our residential and industrial furnaces. Fertilizers, pesticides, factory farms, and high-yield crops from the laboratory substitute, at the margin, for some three-quarters of the acres once needed to produce equivalent amounts of food. It is by extending human enterprise into the third dimension that we painlessly retreat from the two-dimensional surface, where the rest of life dwells. Cities expand skyward and extract their building materials and fuels from the depths of the earth: they exert their pressure on the planet vertically, not horizontally.

Moving our economy into the third dimension has required one input above all others: capital. It takes vast amounts of it to extract oil from two miles beneath Alaskan ice or Saudi sand, or to process the oil into plastics that then displace teak and ivory, or to reconfigure the genes that quadruple yields on the farm. From wood to coal to oil to uranium, the higher the technology, the more capital it requires to burn it, and the less natural resource. And you don't raise capital down on the farm, alongside the hogs. You raise it on Wall Street, among the bulls.

The second crucial input to the three-dimensional economy has been knowledge. Oil two miles beneath Alaskan ice or Saudi sand is not "wealth" at all. It doesn't belong to anyone, least of all to "the world." We call such things "resources" by convention, but the "resource" is not the stuff itself; it's knowing how to get it. Anyone can gather wood and burn it—man has been doing that successfully for tens of thousands of years. Gathering and burning uranium is very much harder, but a tiny volume of it, prepared just so, can heat and light an entire city.

And it takes more of the same—knowledge—to convert oil into solar-power-enhancing additives: fertilizers and pesticides, both of which help us use less sun to put more food on the table. It takes still more knowledge to breed and bioengineer high-yield crops, develop growth hormones for our livestock, use better preservatives, package in spoilage-retarding plastic, and irradiate our food—which all promote the same efficiency: more usable food from less sun. These are the technologies, in other words, that have so dramatically increased the useful yield of each acre of farm or range. And overwhelmingly, they have emerged from the great centers of learning—established, of course, in the metropolis.

The city itself is all the more kind to the environment, because it has so completely rejected the policies that the green establishment holds dearest. It shuns "renewables." The city isn't animal or vegetable; it's mineral.

Start with construction. The city certainly favors non-renewable resources here, and about that, at least, the green establishment remains silent, as it should. America currently harvests about 240 million tons of wood off the land each year, almost all of it for construction. The city, however, prefers to build with the three-dimensional resources, steel and concrete. Those materials can hold up a skyscraper; renewable wood can't. Even if it could, nobody imagines that it would be greener to build with materials harvested from the living surface, no matter where the trees grew, no matter how delicately they might be harvested. The way we build things now, a comparatively tiny area of land yields, from far beneath its surface, all the mineral resources that it takes to build a city. You can't get any greener than that.

The energy picture looks much the same. There's no way the city could ever adopt the green establishment's "renewable" path to energy. Manhattan is never going to heat its buildings or power its computers with rooftop solar cells, biomass, or windmills. There's nowhere near enough rooftop or wind, and no biomass to speak of, other than the mass of the people. Live on a good-size spread in the country, and harvest it aggressively, and you can plausibly imagine living off the renewable sources of energy the greens so strongly favor. Live in the city, and you can't, not on your own acres. You have no acres. Nevertheless, you have tremendous energy efficiency when your energy comes from an oil well and a refinery and gets delivered by a tanker: the supplies are highly concentrated to begin with, and it takes relatively little energy to deliver them to a highly concentrated point of use, like a city.

Cities have become environment-friendly by rejecting the greens' food policies, too—the policies that emphasize organic farming, free of bioengineered seeds and man-made fertilizers and pesticides. When food is grown or raised in the agricultural counterpart to the oil well—the mammoth factory farm, outfitted with every high-tech innovation—it takes relatively little land to produce it in the first place, and it takes little additional energy to deliver it to the tightly packed city.

Three-dimensional resources perfectly complement the three-dimensional city: they are as concentrated in their production as the city is in its consumption. The city is green not only because its residents occupy little land, but because its non-green sources of building materials, fuel, and food—and their delivery systems—can be frugal with land, too. Adopt the greens' energy policies and we'd be blanketing the rest of the state with solar cells and cornfields just to fuel New York City.

As steel-for-wood trade-offs make clear, the city isn't green because it uses little stuff overall, but because it uses little of the stuff that must be culled from the surface of the land outside the city. The Sierra Club labors to convince itself that city dwellers actually use less of a whole grab bag of "resources": copper pipe, heating fuel, postal delivery, and personal cars, for example—an endless catalog of things said to be scarce, dangerous, prone to pollute, or otherwise hostile to the planet. But this kind of accounting is a distraction. If performed honestly, it inevitably leads to the environmentally ruinous conclusion that living in the country is greener, all in all, than living in the city.

To begin with, any honest accounting of copper, fuel, and such must surely allow for the serious inefficiencies that congestion causes. The city may be efficient as long as you are sitting still, but the moment you try to move—yourself to the Met, or a sofa to your apartment—you find that the city is not efficient at all. A city at rest (an utterly oxymoronic notion, of course) may be frugal with its resources, but a city in motion never can be, because the friction is so high. Driving a car fewer miles is no great virtue in city traffic; ten cars idling in gridlock can burn fuel quite as fast as a single car does cruising down a wide-open highway. Green bookkeepers count efficiency as a very serious credit in almost all other contexts, so why not give green credit to the "efficient" country over the city, too, for its free- flowing traffic?

It gets worse. Being the center of capital and knowledge that it is, the city makes its inhabitants much richer than their country cousins. And when all the accounts are finally in, richer people invariably consume more of just about everything. If you're not spending your extra wealth to heat your apartment on the Upper East Side, then you're probably spending it to vacation in the snow farther west, in Aspen. If you don't drive a car much in the city, you probably fly more planes out of it. Moreover, you may not consume much copper and fuel yourself, but Saks and the Met consume some on your behalf; so do taxi drivers and delivery trucks and airplanes. To find out how much you and your neighbors consume in this indirect way, you don't have to whip out a tape to measure copper pipes. Just measure spending. And city dwellers spend more, because they have more to spend.

The only thing they evidently don't get with their higher wealth is more land. Rich as they are, they can't afford to. A rather small area of virtual land 12 stories above the edge of Central Park costs far more than a farm and 100 acres in Vermont. Life in the city is incontestably frugal with the one thing that should eclipse all others in environmental discourse: land.

By building the city up out of non-renewable resources, by heating and lighting it with non-renewable fuels, and by feeding it with non-organic foods preserved with chemicals or plastic packaging, the city returns acre upon acre of land in the country to wilderness, the greenest accomplishment of all. And in doing that, the hard city and its hard fuels take care of a lot of pollution, too. Nature has enormous power to cleanse and restore; freeing up 95 million acres to be reclaimed by watershed and forest has surely done more to clean water and protect birds than the curtailing of pesticides ever achieved. The best estimates at hand likewise indicate that forest regrowth in America currently recaptures all the carbon and then some that America releases into the air in burning fossil fuels.

With food and fuel, the greens keep trying to spread things back out again—that's the whole thrust of the food and energy policies they so tirelessly promote. It's a mistake. But, contradictorily, their plan to improve on the city is to pile it up all the higher—by collaring and quaran- tining the metropolis and choking off suburban sprawl. That's a mistake, too.

The organic growth of the city is what has made possible the greening of the country. Manhattan itself would be greener today if its sprawl had been collared off about mid-island in 1840, but the Empire State wouldn't be, nor would the rest of America. The city absorbs people, enriches them, affords them the confidence and security to have smaller families, and generates the capital and knowledge that move the production of food and energy off the land and into the third dimension.

Suburbs may indeed consume more material resources than cities; they certainly consume more land. But rural living consumes even more land: land is the one thing rural life tends to consume in profligate excess, because the country is the one place where land is really cheap. Viewing the suburb as mere spillover from the city is just plain wrong, demographically speaking. On their own cities don't spill out; they collapse in, because on their own cities have negative population growth. Cities grow not because they sprawl out from the center, but because they draw people in from the periphery—the distant periphery, far beyond the suburbs.

If bad policies do somehow manage to collar the city with an impregnable ring of green, the city will stop drawing people in from the country and begin sending them back out instead. As cyber-visionaries keep telling us, one doesn't have to stay in the city anymore to stay at the center of the new economy; the virtual city is where it's at, and given the choice, quite a few people may happily bid the concrete city good-bye. Chips and communications networks are centrifugal technologies; they make it easier to spread apart. They are very powerful already and grow more so month by month. In these circumstances, the most likely effect of collaring the city will be to spin people out farther still, well beyond the suburbs. "[T]he digital world [will] redistribute jobs and wealth, so that the concentration of opportunity need not parallel the concentration of people," declares cyber-pundit Nicholas Negroponte in Wired. "[T]he flow of people will be out of, not into, cities. . . . Being rural could become synonymous with being rich." Bad news for the city, if he's right. And even worse news for the wilderness.

Happily for the environment, Negroponte's digital diaspora hasn't shown up in any hard demographic data yet. And it won't, not so long as there remains the option of the healthy suburb—something most people find even more attractive than rural solitude. So long as city and suburb continue to prosper and grow, the centripetal attractions of the city will overcome the centrifugal power of bits. Indeed, as one of us has argued in these pages previously ["New York, Capital of the Information Age," Winter 1995], gigabit links to the rest of the planet could well make Citicorp, Saks, and the Met more dominant than ever, by letting them project their top-of-the-heap talent even further outward than they do today.

The right perspective is to view suburbs and city as a single economic entity, growing organically together. The suburbs wouldn't exist but for the city and its jobs and money. The city can't survive without its suburbs, which is where the human capital finds refuge from the city's worst excesses and pathologies. Without capacious suburbs, the city will simply lose altogether the people who provide the capital and knowledge that make cities so efficient: no green collar will ever persuade such people to live in places with lousy schools and high crime.

The real threat to the environment isn't that the city will continue to grow, but that it won't. The suburbs are the best defense against the rural alternative, an alternative made newly attractive today by the decentralizing technologies of the information revolution. The suburb is the buffer that lets the married with children stay near the city when they tire of living right in it, leaving room for new young immigrants in the heart of the city itself. Collar the city, halt its natural slope into suburbs, and the young, well-wired digirati may choose the country instead, as soon as their kids arrive. The city will lose, and the wilderness will lose too.

There was abroad, at one time, the notion that cities grew parasitically off the countryside, that all economic wealth derived from the land, and that the city grew rich only by expropriating the bounty of honest folk who tilled the soil. If this were ever true, it's no longer true today. The industrial revolution severed half the links between wealth and land; the information revolution has severed most of the rest. Wealth now springs from the third dimension, beneath the surface, and from the fourth, the boundless caverns of the mind. The city, its capital, and its knowledge are the fonts of those kinds of wealth. Their ultimate effect is to make land far from the city uneconomic. Which returns it to wilderness, 100 percent green.



By packing people into a small area and by using high-tech foods, fuel, and building materials, cities leave most of the earth free for wilderness.
City Journal Winter 2000.
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