The world is going through a massive urbanization, overturning the traditional demographic order and challenging two millennia of literary and cultural concepts of the urban. In this last post, I want to return to the ecological impacts of that urbanization…and what conservationists can do to mitigate it.

The ecological implications of an increasingly urban world are in an important sense different than the demographic or metaphorical implications. In a world where humanity is overwhelmingly urban, our population dynamics or our cultural evolution will be mostly disconnected with what is happening in rural parts of the world. However, an urban world is still intensely linked with rural areas ecologically — we all need food.

During the long period of history where we were hunter-gatherers, humans had relatively little mastery of nature and the environment. Granted, our species was flexible enough to survive in many different environments, and we were skillful in extracting resources to feed ourselves.

One theory, the prehistoric overkill hypothesis, dates the extinction of many large mammals in North America to the arrival of human hunters. Still, many environmental changes were beyond our control. Most hunter-gatherers are only one or two bad seasons away from starvation, and average lifespan of different hunter-gather groups varied from 21 to 37 years. Compared to what was to come later, the degree of human mastery of the environment was low.

As the agricultural revolution occurred and cities began to be possible, human mastery of the environment expanded. One theme since the agricultural revolution has been a larger and larger percent of resources moving from rural areas to cities: Man was domesticating nature not just to feed farmers better, but to feed its growing cities.

This trend can perhaps best be seen with statistics on the amount of land was needed to support one person. Hunter-gather cultures in Mesopotamia could support less than one person per square kilometer. Agricultural productivity increased this more than 10-fold.

And agricultural productivity continued to increase over time. In the mid-18th century in Europe, one square kilometer of cropland might support 40-60 people. Currently, wheat farms using the best available technology might get 45 bushels from an acre, which is around 10 million calories per square kilometer — enough to feed 5,000 people per square kilometer.

This process of increased productivity, and the myriad other ways humanity has domesticated nature, has reached an astonishing scale. One estimate is that globally, humanity appropriates between 10% and 55% of all terrestrial biological productivity that exists on Earth.

As humanity moves into our first century, burgeoning urban populations will put increased demands on the environment. These increased needs will by necessity further increase our domestication of nature. Whatever wilderness that remains will either be because we can find no easy way to exploit it, or because urban dwellers want it to exist, as a playground or as a source of inspiration. The 96% of the Earth’s surface not in cities will increasingly be shaped by the wants of urban dwellers, many of whom may know little about it. The rural world will become the urbanites dream of what the rural should be.

So, how do you do conservation in an urbanizing world?

Encouraging greater efficiency: First, anything that makes cities more efficient — in terms of resources or energy — will lessen the impact of urban dwellers on the broader world. These kinds of efficiency considerations are not the kind of thing that conservation organizations, used to thinking about diversity in mostly rural landscapes, usually put much time into. But in an urbanizing world these considerations become much more important, because much of what is happening in rural places is because of demand by urban dwellers.

Climate change highlights this importance, because how the next great cities of Asia and Africa are built and where they get their energy will in large part determine how bad climate change gets and how much biodiversity we lose. For example, how much the average Chinese (or American) citizen drives, and how fuel efficient their car is, matters a great deal to the ecological viability of every Nature Conservancy preserve on Earth.

Cultivating a conservation ethic. Second, and probably more important, conservationists need to make sure that the next great cities of Asia and Africa are full of people who care about the environment and want to protect the wild spaces that are left.

Several people have pushed me for specific ideas on how to reach out to urban dwellers, and I don’t have any brilliant new ideas. My reading of history in the United States and Europe is that two key things are needed to make sure urban dwellers are dedicated conservationists:

  1. Environmental movements that affect life in the city and make it better, whether it’s neighborhood parks or clean water; and
  2. Close contact with wild natural places at some point in their lives.

And there’s every indication that both those things will be needed to continue to have support for conservation in an urbanizing world.

(Image: Kestrel in Melbourne, Australia. Image credit: mugley/Flickr through a Creative Commons license.)

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  1. I believe that idea 2 under ‘Cultivating a conservation ethic’ should start with young children in school.

    Children generally have a love for animals and a natural curiosity. We need to make sure they get positive exposure to the outdoors, instill the idea that nature belongs to them (everyone), and encourage them to protect it because it belongs to them (everyone).

    Hopefully they will then start to pass this love down, generation after generation. Let’s get it done!

  2. Just a note that average lifespans are misleading, as they include the large number of individuals who never mature past age 5. The lower the technology, the greater the percentage who die in childhood. Average lifespan is not the same as typical adult lifespan

  3. I have often wished that TNC did more to promote a conservation ethic inside our cities – not just “out there” in the hinterlands where there aren’t any people.

    Environmentalists – and especially old-line environmentalists of the last generation – tend to forget that humans, and our cities, are part of nature too – a pretty damned important part of nature in the modern world.

    Cities hold a lot of potential solutions to our contemporary environmental problems – mostly stemming from the fact that they’re more energy-efficient, but also from the fact that (especially in developing nations) they offer poor people an opportunity to escape grinding poverty and the over-exploitation of rural resources.

    In spite of that, I still see an anti-urban bias among environmentalists and our environmental nonprofits. There’s this idea that if we all built cabins in the woods as Thoreau did, we’d be saved. But as you point out, the planet can’t support 6 billion hunter-gatherers. And besides, the real Thoreau was a pencil manufacturer who embraced technology, modernity, and the sociability of town life.

    I write a blog ( that’s devoted to helping people find and appreciate the wild nature that exists even in our largest cities. I look forward to seeing more work from TNC that’s focused on bringing a new appreciation for wildness into the planet’s urban areas.

  4. Isn’t it really the increase in population, as opposed to an increase in urbanism that threatens conservation? Now sprawling suburbs are a different story than true urbanism. In fact, I find that true urbanism – dense, multi-use, walkable, bikeable, transit-oriented neighborhoods – is actually more in tune with conservation than rural living, which is often car-dependent.

    I would suggest the slow food/buy local movement that is spreading like wild fire right now among urban dwellers is a strong place to connect.

  5. Cities are inherently more efficient than rural landscapes, as several commenters noted. In the most efficient cities such as New York, carbon emissions per person are only 25% of the US average (with well over 50% of all trips made by walking, biking, subway). While we argue about reducing carbon emissions maybe 10% by using solar panels and electric cars, we could reduce them by 70% or more by converting suburban and rural sprawlvilles into walkable, bikable places with a real heart. European emissions per person are already 50% below US levels primarily because their places are better designed, and they have a higher quality of life than we do.

  6. “Environmental movements that affect life in the city and make it better, whether it’s neighborhood parks or clean water”

    Right now my neighborhood is working on urban agriculture. We don’t have much room so it’s just going to be a small vegetable plot.But that’s another way for people to get involved. It adds some green to the area and plus people get to eat healthier.

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