If you look after the country, the country will look after you.
—Aboriginal saying1
Every tree’s life matters in Melbourne.
To encourage developers to design projects with minimum removal of trees, every publicly owned tree in the city has a financial value—$100,000 or more for a big, mature elm—that must be paid if construction plans are not altered to avoid its removal. To prevent damage to trees during development, projects must set aside money to insure against potential injury. Each of Melbourne’s seventy-seven thousand trees in public space has its own symbol on the city’s digital urban-forest map. A click on the orange dot near the corner of Elizabeth and Collins Streets, a downtown intersection, reveals a London planetree, ID#1024658. It is in decline, a pop-up box discloses, with less than half of its leaf canopy and maybe ten more years to live. Another click provides an email template; you can write to this tree, expressing admiration, asking it a question. Every tree in the city also has advocates in a ten-person city-government unit of foresters, ecologists, and an arboriculturalist and among residents of the city’s precincts and conservation and horticultural organizations.
Until 2009, Melbourne, a coastal city of fourteen square miles and 140,000 residents in a much larger, sprawling metropolitan region, cared for its trees much as other cities did—mostly as amenities that enhanced city life. Settlers in the nineteenth century had set aside land for public parks and gardens and planted trees, favoring species that recalled Britain’s trees, that could have value as timber supply or were considered to have health-giving properties. In the twentieth century, though, a history of the city’s forest explains, “Melbourne was keen to be seen as a modern and Australian city” and planted trees that formed avenues, shapes, and colors “popular in global urban landscaping trends.”2 For today’s residents, the trees are a key characteristic of Melbourne’s identity as Australia’s “garden city.”
Then came the worst drought in Melbourne’s recorded history—a twelve-year dry spell that lasted into 2009. Annual rainfall declined more than 25 percent on average between 2002 and 2009,3 and water-level capacity plunged to about 25 percent of normal. Heat waves killed hundreds of people. Low availability of water killed trees and shortened the life expectancy of others. Residents adapted, cutting water use 50 percent and buying rainwater-holding tanks, while the city invested in a pipeline to deliver water over mountains.4 To save water, city officials removed trees lining streets and drastically reduced irrigation of public greenery—until community concerns about the declining state of urban trees prompted a change.
“The drought made us rethink about water and trees,” says Ian Shears, the city’s urban-sustainability manager. Melbourne’s many older trees—those lining boulevards and in parks are more than one hundred years old—were especially vulnerable to the harsh conditions, as were irrigated trees. Climate scientists predicted that average annual temperatures would keep rising, with twice as many days of extreme heat (above 95° Fahrenheit), less annual rainfall, and more extreme storms. All of this would increase stress on trees and damage caused by pests, diseases, and soil erosion. By 2030, it was estimated, 39 percent of the city’s trees would be ending their useful lives. “There was the realization,” says Shears, “that an asset was being lost that people thought was always going to be there.”
At the time, Shears, armed with a graduate degree in horticulture and a city job as a steward of the urban landscape, saw a strategic opportunity. “The loss of a lot of green and the potential loss of the big trees really drew people up short,” he says. “I used that as a stepping stone to say, look, we have to do something, so what is it we should do?” He and his colleagues started talking about an idea unused in the city: “urban forestry,” a practice developed in the 1960s in Canada, which recognizes that urban trees and other vegetation are part of a city’s essential infrastructure and provide environmental, social, and economic benefits, not just recreational and amenity value. Thinking about the trees this way, says Shears, “changes people’s paradigm about what a city can and should be. We live within a green infrastructure and it’s just as important as transport, telecommunications, etcetera.”
The new framing focused the community’s conversation on the city’s broader relationship with nature, starting with its trees. “The way we’ve established our city has been in spite of nature rather than with it,” Shears observes. “What we needed to do was recognize that if we work with nature, and if nature is at the heart of our urban design, then we’ll be able to have a much higher livability within the city.”
Melbourne’s award-winning plan to strengthen its urban forest, unveiled in 2012, identified a wide range of potential benefits. The forest provides shade that cools the city and reduces flows of storm water and nutrients—nitrogen, phosphorous, and heavy metals—into waterways. It reduces air pollution and greenhouse gas emissions. It provides wildlife with habitats and enhances biodiversity of an area. It helps a community build local identity, brings people together, encourages outdoor activity, and improves mental well-being. It reduces energy costs, increases property values, avoids infrastructure damage, decreases health costs, stores and sequesters carbon emissions, and plays a role in marketing the city as an attractive setting.
The forestry plan, Shears says, “has something for everybody in it. What’s been fantastic—the community wants it. Every time we go out and have a conversation with people, they exhibit a palpable desire for more green in their lives. Look, there are a lot of pressures in living in Melbourne. Climate change is with us. Extreme heat days are going up. There’s rapid population growth—they’re saying that by 2050 Melbourne’s going to double in population. People are feeling the effects of urbanism hitting them very heavily. Whether consciously or subconsciously, there’s a desire to get in touch with nature.”
Obtaining nature’s benefits, for Melbourne, involves more than just planting trees. The city has to undo its development patterns—the design and use of space—and change them for a future of even more development, when many more residents, workers, and visitors will be present. Development has left most of Melbourne without substantial tree canopy and shade. It covered the land with impervious hard surfaces—paved roads, streets, sidewalks, parking lots, and building roofs—that keep water out of the soil, channeling it into an extensive built drainage system that empties into the city’s river and bay. The combination of hard surfaces and low vegetation cover, as well as the use of vehicles and air conditioners, contributes to the urban “heat-island” effect that makes the city warmer—by 7 to 12° Fahrenheit—than nearby suburban and rural areas, especially at night. Even the way the city has irrigated its parks and gardens for many years proves to be a problem. Surface irrigation encouraged trees to develop superficial root systems that did little to support soil moisture and left trees vulnerable when irrigation ceased. The city needs “water-sensitive” urban design—permeable paving, rain gardens, green roofs and walls, and other green infrastructure—to promote healthy growth of vegetation.
What unfolded in Melbourne during the years after the drought followed much the same winding pathway you’d see in other leading-edge cities engaged in renaturing: rounds of technical analysis and planning; extensive community-engagement processes; goal and target setting by elected officials and top government managers; design and implementation of new policies, demonstration pilots, and bigger projects; and the gradual embedding of new thinking into the city’s regulatory, budgetary, and other deep operating structures. Melbourne developed extensive plans for urban forestry, open space, biodiversity, climate adaptation, regional resilience, and management of water, the “blue” that is essential for keeping a city’s “green” healthy and growing. These provided the city’s big-picture destination—a set of broad goals—and a roadmap at the citywide scale. They became the basis for development of precinct-level and water catchment–area plans that set the context and criteria for prioritizing potential projects.
To drive change at an ambitious but feasible pace, the city adopted a set of citywide targets for increasing its tree canopy, diversifying the urban forest’s tree species, expanding green space in the city, increasing permeable surfaces, increasing understory plants—small trees, shrubs, vines, and grasses—on city land, and boosting municipal water sourced from non-drinking water sources such as reused rainwater and storm water and recycled wastewater.
Since 2012, the city has spent about $8 million a year on its urban-forestry strategy and planted about three thousand trees a year5—on the way to adding as many as fifty thousand trees. It adopted a Tree Retention and Protection Policy that put a dollar value on every tree. “If a new building is going up in the city and they need to take out two trees to do it,” Shears explains, “we will go through all lengths possible to keep the trees. If we can’t, then the developer pays the value of those trees and for regreening the site.” In 2016, the city collected about $700,000 for trees that had to be removed—funds it invested in its greening strategy. Developers also have to provide financial guarantees for trees that could be injured or killed during a site-development process. By mid-2017, developers had put up a total of nearly $5 million in bonds to cover 267 trees at risk. Putting a price on trees often causes developers to change their plans for sites, Shears says, as they try to avoid the potential costs.
In 2013, the city launched its digital map of the city’s trees and an email channel to connect to any tree (map at www.melbourneurbanforestvisual.com). “Everybody loves trees, but if you express a love for a tree, you’re seen as a bearded tree hugger who wants to protect forests from logging,” says Shears. “We decided we needed a way to enable bankers in suits to show their desire for trees. The emails to trees become this twenty-first-century technological way to hug a tree.” Thousands of emails have been received.
In May 2017, the city unveiled an Urban Forest Fund, with about $1 million in initial capital, to promote the greening of privately owned property, which contains twenty thousand trees. “Our existing strategies have ticked most of the boxes of the public realm,” Shears explains, “but the next really big step is to start to influence what happens in the private realm—land and rooftops—and how that can come together with the public strategy.” The fund offers to match private investments in green roofs, walls, and facades and other greening projects.6
In 2018, the city approved regulations for privately owned green roofs, walls, and facades, culminating a twelve-year effort to set new rules in place.
Melbourne’s many greening efforts have had two major effects, Shears says. “We’re in a really new place. We’ve raised awareness, created knowledge, and created the desire of people to participate.” This, in turn, has helped get city officials on board with massive greening: “We’ve been able to demonstrate to our elected officials that this is what the community’s demanding.”
To obtain an extensive array of nature’s benefits, Melbourne and other cities—Portland, Oslo, San Francisco, Singapore, to name a few—have advanced comprehensive, multifaceted, citywide approaches.
These communities are embracing a far-reaching shift in their mental models about the city’s relationship to nature. In modern times, the city has been thought of as the dominant context in the natural environment; its physical, economic, and social needs were to be met by shaping the landscape near and far. To do this, cities cleared and built upon the land, sweeping away natural habitats and species. They engineered control over waterways, consumed vast amounts of natural resources, and dumped enormous amounts of waste. Their inhabitants lost direct connection with the natural world and its processes. Urban areas did contain parks, garden areas, and tree-lined streets, but these mostly were limited “postage-stamp” parcels in the larger urban scheme of things.
In the 1800s, Melbourne, Vancouver, San Francisco, and other new cities exploded into existence. Historical geographer Gray Brechin describes the transformative effect of San Francisco’s growth on a windswept peninsula without freshwater or firewood: “Forests were leveled on all Pacific shores, rivers and lakes vanished, and the bay from which the city took its name was filled, poisoned, and plundered, while wildlife and natives within the vortex were speedily exterminated.”7 Older cities—London, Boston, New York, Berlin, Tokyo, Shanghai, and others—expanded horizontally and vertically. By 1987, the Brundtland Report on sustainable development was warning that an “urban challenge”—the unhealthy and degrading environments of cities in a rapidly urbanizing world—stood in the way of managing environmental resources to ensure sustainable human progress and human survival.8
Many factors explain the modern transformation: population growth, the desire for improved material well-being, development of unfettered markets for goods and property, and society’s increased technological prowess harnessed to cheap, portable supplies of fossil-fuel energy. But ideas mattered too. Religions upheld the dominion of people over nature. Especially in Western society, the notion took hold of the primacy of human agency.9 Cities, says Richard Register, urban ecologist and designer, generated a kind of human creativity unknown in the collective, careful, slow-moving villages that preceded them. It was “specialized, narrow, blind to its long-range effects, and powerful in its new integration of ideas, tools, and products.” It quickened the pace of change, “bringing the novelty of conspicuous change into the short span of a single lifetime and giving people the experience of witnessing personal creativity right before their eyes.” The village’s cyclical sense of time “was transformed into a vector later thought of as Progress. In the brief cycle of one life, the personality could now see oneself as participating in the process of change in society and nature, experiencing a tiny shred of earthly immortality and god-like creativity, causing something to actually happen and be part of a permanent change.”10
The rise of self-importance has been pervasive, observes landscape ecologist Eric Sanderson, author of best-selling Mannahatta, about mapping the natural ecology of Manhattan Island before Western settlement: “It is a conceit of New York City—the concrete city, the steel metropolis, Batman’s Gotham—to think it is a place outside of nature, a place where humanity has completely triumphed over the forces of the natural world, where a person can do and be anything without limit or consequence.”11
Another key modern idea that transformed urban areas was embedded in the scientific way of analyzing the world in parts rather than as a whole. The natural world was seen as a set of distinct resources—land, water, minerals, animals, plants, and so on. In cities, land was treated “as a commodity to be divided among different uses rather than as a living, complex, integrated ecosystem,” explain urban planners Jonathan Barnett and Larry Beasley. As a result, “there is often a serious mismatch between what is permitted—or required—and the actual ability of the landscape to survive such changes.”12
As urban denaturing proliferated in the nineteenth and twentieth centuries, conservation and environmental movements arose to protect and preserve natural spaces—outside of cities. “You enjoyed nature by leaving the city and going to visit someplace: Yosemite, Yellowstone,” reflects Timothy Beatley, a professor of sustainable communities and prominent advocate of green urbanism. Today, nearly 15 percent of all land on the planet is under some type of protected status.13 Other efforts added public parks within the city to provide residents with relief from urban stresses and improve public health. Some urban designers promoted the development of “garden cities,” smaller communities that contained green space and were surrounded by green belts. However, as Beatley notes, “most visions of a modernist city seemed not to include nature.”
The emerging idea inverts the modern-city hierarchy, restoring nature, instead of the city, as the dominant context. “We’re discovering,” Beatley says, “that a modern city should understand itself as a city in nature.” Melbourne, whose residents have cherished the forest within their city, now talks instead about being a city within a forest. Singapore, a dense city-nation of more than five million people, once envisioned itself as a city with gardens but now sees itself as a city within a garden. The city remains the shaper of its built environment, but it shapes with an altered perspective.
The idea of renaturing cities is being applied at multiple urban scales. In the 1990s, promotion of green buildings—structures designed and constructed to be environmentally friendly and energy- and water-efficient—began to influence the development of individual building sites in cities. At the time, these were viewed curiously by North American cities, but that has changed. In the US, National Geographic reports, spending on green construction hit about $125 billion in 2014, more than twelve times the level in 2005, and by 2018, green construction could “account for one-third of the entire construction sector.”14
The whole city came to be understood as an “urban ecology,” the complex dynamics and interplay of multiple natural ecosystems, with many animal and plant species, built systems, and flows and exchanges of materials and energy. The scientific concept of an ecosystem, a living natural system, was formulated in the 1930s, while the concept of urban ecology, the study of distinct city-based ecosystems, emerged in the 1970s. Now the urban ecosystem has become a crucial scale of analysis and city planning, as reflected in Melbourne’s approach.
Cities also apply renaturing to the scale of the neighborhood, district, and precinct. Melbourne’s overall urban-forest plan, for instance, includes tree canopy–building plans for each of the city’s ten precincts that the city codesigned with community members. The district scale is significant because ecosystems and environmental conditions, as well as vulnerability to flooding and heat, vary throughout an urban area.
Part of urban renaturing is a restorative exercise, a way to reinstate balance and sustainability to the city’s relationship with nature. Another part introduces new designs to a city’s space. “It is a bit ‘back to the future,’ but it’s also a creative new future,” says Beatley. “There are elements of the old, but there are entirely new things: the incorporation of nature into the vertical realm [walls and facades of buildings], for instance. Even the notion of ‘hybrid nature’ as seen in Singapore’s ‘super trees’: large, human-designed and built metal objects that house living plants.”
The green future of a city like Melbourne, says Ian Shears, “goes well beyond the European thinking that’s led to these major avenues, big broad streets, and stunning trees. It’s not the imposition of the European mind-set on Melbourne’s ecology, it’s the development and understanding of a uniquely Melbourne ecology.” That doesn’t just mean going back to a previous ecology; climate change makes that unfeasible and scientific knowledge about forests offers new options. “When we think about which trees will be good trees for Melbourne into the future,” Shears says, “it doesn’t matter whether it comes from Melbourne or Mozambique. What matters is, it needs to survive in a changing environment and it needs to give us the best environmental services it can.”
When cities renature themselves, they pursue three distinct, interrelated applications of the idea. They expand the use of green infrastructure. They protect and enhance ecosystems and biodiversity. And they provide people with ways to immerse in nature. Each of these methods involves innovative practices used at multiple urban scales, and each applies to new developments on “virgin” or cleared sites and to retrofitting of densely built parts of the city.
Cities use various green-infrastructure methods—rain gardens, rainwater harvesting, bioswales, permeable pavement, tree canopies, green space, green roofs and walls, constructed wetlands, and more—to address excess storm water, excess heat, rising sea levels, and other practical problems. This is not a new practice; for centuries, architects, builders, landscapers, and city planners have tapped nature’s capabilities to absorb and channel water and to cool the air. But in just the past few decades, green infrastructure has gained significant momentum in local government planning and policy worldwide as a favored way to respond to climate change and to increase cities’ sustainability and appeal. The impetus stems from three factors.
Experimentation and research are increasing the performance predictability and reliability of green infrastructure. The US Environmental Protection Agency’s website alone contains links to more than fifty performance studies and databases and numerous other scientific and regulatory agency research, modeling tools for designing and costing, guidebooks for operations and maintenance, and design manuals.15
Cities find that using green infrastructure instead of or in combination with “gray, hard” infrastructure can provide cost savings—reducing initial construction costs and holding down operational and maintenance costs due to less need for labor and heavy equipment. This is especially true when it is used for storm-water management.
Green infrastructure can deliver other important value for a city, such as improved water and air quality, upgraded habitat, and increased recreational space. Cities can quantify these benefits, measuring reduction in air pollutants and chronic diseases, for example, and they can assess the financial value of the benefits so that a return on investment in green infrastructure can be assessed.
As cities recognize the increased reliability, cost effectiveness, and cobenefits of green infrastructure, they have expanded the practice from one-off projects to city-scale approaches.
When Copenhagen faced a substantial increase in the frequency and intensity of rainfall, it decided not to expand its sewer system, an expensive “hard” approach to managing excess precipitation. Instead, the city selected a neighborhood, St. Kjeld, as a test site for green infrastructure designed to manage heavy rainfalls, aiming to turn 20 percent of the district’s paved surface into green areas and to retain and manage 30 percent of rainwater rather than have it end up in sewers. The approach prevented damage and traffic disruption during heavy downpours. Then the city committed to invest as much as $4 billion over fifteen years for three hundred projects that take the green-infrastructure approach citywide.
When Rotterdam developed its citywide climate-adaptation plan, it selected a neighborhood, the Zoho, in which to pilot the combined use of many green-infrastructure innovations designed to work together to capture, store, and use rainwater or slowly release it into the ground, rather than channeling it to overloaded sewers. The innovations together function as a district-wide “sponge” for water. “These measures are particularly effective in areas with high consumer pressure and little available space, such as the compact city centre and the neighbouring urban districts,” notes the city’s adaptation plan.16 The Zoho is a bustling nineteenth-century district with modern buildings and streets. Green infrastructure—soil, plants, trees, and gardens on roofs, in streets, along the facades of buildings—is taking over. Pavement on underused streets and roads has been replaced with permeable pavement that allows rain to filter through into the ground. Rain barrels collect water for reuse in buildings. The district’s greenery works in combination with gray infrastructure. At the district’s heart sits the Benthemplein Water Square, the world’s first water square—a large public space for mingling, events, and recreation that also serves as a giant rainwater collector.17
A number of leading-edge cities have launched efforts to protect and restore the ecosystems and biodiversity of their urban regions. They want to ensure and enhance the delivery of essential services provided by nature outside, as well as inside, their boundaries.
Melbourne’s attention to its urban forest evolved into broader concerns about nature and the city. In various planning processes, it looked at the regional ecosystems of which the city was a part and on which it depended and their animal and plant biodiversity. “By considering our city as a wider ecosystem, there is the opportunity to actively foster connections amongst people, plants, animals, and the landscape,” declares the city’s “Nature in the City” report. Especially important is the Yarra River, 150 miles long, starting in pristine mountain forests, running through the city, and ending in the sea—covering a catchment area of nearly 1,600 square miles, more than one hundred times larger than the city. The river is the city’s lifeblood, one report declared; it provides water supply; supports agriculture, industry, and recreational activities; transports people and goods; and enables urban development.18 The river, like the city’s trees, is an essential part of Melbourne’s identity and well-being.
In San Francisco, the five feet of sea-level rise projected to occur by 2100 could inundate highways, airports, and some of the estimated $75 billion of property on the city’s shoreline. In response, the city and eight urban counties ringing the San Francisco Bay decided in 2016 to invest $500 million to restore and expand the Bay’s wetlands, a vast tidal-marsh ecosystem that for a century-and-a-half had been severely altered by people. “As the population grew,” writes environmental journalist Jane Kay, “newcomers from around the world brought a diversity of lifestyles, filled the tidal marshes, dumped mine tailings, and brought exotic species by railroad and ship. Later came dams, sewage, oil refineries, and plastic pollution.”19 The two-hundred-thousand-acre estuary shrank to about forty thousand acres in 1999. But now the Bay is expected to serve as a natural buffer against storm surges and rising high tides, absorbing water and energy; assessments have called for the addition of sixty thousand acres of marshland. This type of restoration is a newly valued environmental service for many of the world’s cities built where rivers meet the ocean.
In 2015, Vancouver released its “Greenest City 2020 Action Plan,” with urban-greening goals of leading the world in green building design and construction, planting 150,000 new trees, ensuring every resident lives within a five-minute walk of green space, and increasing the number of urban farming businesses, farmers’ markets, and community gardens. But the city also recognized that its water supply, food system, and air quality depended in large part on what happens outside the city’s borders.20 Its drinking water, for instance, comes from reservoirs fed by a 202-square-mile watershed that captures rainwater and snowpack melt. Production of food in the region relies on having agricultural lands. And the city’s relatively clean air—under threat from population growth that could increase transportation exhaust and from climate warming that could increase forest fires and smoke—can only be maintained through action at regional and provincial levels.
The growing urban attention to ecosystems extends to maintaining and increasing an urban region’s biodiversity, which is key to maintaining ecosystem health. “When we allow one species to die,” explains Edward O. Wilson, “we erase the web of relationships it maintained in life, with consequences that scientists seldom understand . . . we break many threads, and change the ecosystem in ways still impossible to predict.”21 Singapore developed a City Biodiversity Index to measure its biodiversity and assess progress in maintaining and increasing the number of species. The city published a user’s manual in English and Chinese that eighty cities worldwide have used.22
Climate changes have been leading more and more cities to recognize the need to protect and enhance a wide range of ecosystem services. Governments in Western Europe and the US have adopted an ecosystem-services framework for planning processes. “Ecosystem services have recently emerged as a policy priority” for cities, reports the United Kingdom’s Future of Cities project, adding that cities vulnerable to flooding, heat waves, or drought will have reasons to tap more into ecosystems’ benefits.23 A number of environmental and conservation nonprofit organizations, such as The Nature Conservancy (TNC), are helping cities to restore ecosystems. “Restoring source watersheds [of cities] . . . may be a cost-effective approach for cities to reduce drinking water treatment costs while enhancing supply resiliency and protecting biodiversity among other co-benefits,” explains a TNC report.24
Cities generally use a combination of regulation and investments to manage ecosystems, but to date, there isn’t consistency in this emerging urban practice, and cities lack useful data about ecosystems and species. Cities almost always work in partnership with other government entities that also have control over relevant ecosystems. They advocate for tougher regulation and enforcement to prevent pollution and incentives to preserve agricultural lands from development. They also increase their efforts to reduce consumption of water and other natural resources, which can ease pressure on ecosystems. Some cities are instituting new resource-management models, such as integrated water management, which coordinates the traditionally separate functions of providing drinking water, managing storm water, and treating wastewater, as a way of approaching ecosystems as a whole. The plan to protect the Yarra River emphasizes the need for a new management model that covers the length of the river, recognizes community expectations, has an “integrated, overarching strategic plan,” and provides clear accountability.25
Melbourne turned to Aboriginal people for help in thinking about its ecosystem-management strategies. Its “Caring for Country” initiative recognizes that “local knowledge passed down through generations of Aboriginal people can provide great insight into the way land is managed, even in today’s urban context.”26 Researchers in Melbourne note that the Aboriginal perspective on nature is quite different from the modern Western view: Caring for Country “is a practice of resource use whereby human modification and employment of nature nourishes Country rather than degrading it. . . . Embracing Caring for Country into mainstream sustainability work provides avenues to transform Western views of and relationships with nature.”27
Within cities’ many actions, an emerging practice is the financial valuation of ecosystem services, which helps make the case to policymakers for investments in restoration and enhancement. This valuation typically combines different types of value—financial/economic, social/cultural, short- and long-term, environmental, public health, and insurance value—which makes for notably difficult calculations, because each type of value uses a different analytic framework. For now, valuations tend to be more a way of raising awareness of the ecosystem’s services than of providing a rigorous and reliable return-on-investment model for decision making. In some cases, cities have compared the cost of investing in ecosystem-service maintenance and enhancement with the cost of alternative proposals. New York City, which relies on a two-thousand-square-mile upstate watershed to deliver clean, unfiltered water to the city, famously invested $1.5 billion to buy seventy thousand acres in the watershed, protect reservoirs from pollution, and subsidize environmentally friendly economic development. The alternative was to spend $6 billion for a large water-filtration plant. The eye-catching savings prompted more than one hundred other cities to consider watershed conservation—an investment in an ecosystem service—instead of building filtration plants.28
A growing number of cities around the world, including Melbourne and six other climate innovation lab cities—Austin, Oslo, Portland, Rio de Janeiro, San Francisco, Washington, DC—are going beyond green infrastructure and ecosystem and biodiversity restoration to harvest nature’s benefits. They are among the twenty-four city-members of the Biophilic Cities Network—communities working in ten countries to bring more contact with nature into city dwellers’ daily lives.29
The term biophilia was defined three decades ago by biologist Wilson as “the innately emotional affiliation of human beings to other living organisms.” Tim Beatley, who started the Biophilic Cities Network in 2013, describes the basis for “biophilic urbanism”: “Human beings need contact with nature and the natural environment. They need it to be healthy, happy, and productive and to lead meaningful lives. Nature is not optional, but an absolutely essential quality of modern urban life.” Beatley’s 2016 Handbook of Biophilic City Planning and Design cites a range of studies that show exposure to nature provides emotional, mental, and physical benefits, reducing stress, boosting the immune system, aiding in recuperation from surgery, and increasing happiness. The biophilic approach in cities, Beatley says, responds to “long-term chronic stress, the unhealthiness of indoor living, reconnecting us to family and community. It addresses many pathologies of modern life: emptiness and lack of meaning. There’s a hunger for this.”
Cities committed to a biophilic approach focus on increasing the amount and quality of nature that is present in the city—and on improving access to it. They publicly commit to setting biophilic goals, taking initiatives and other actions—including green infrastructure and biodiversity projects—and using indicators to assess progress. Projects range in physical scale, from sites and buildings to citywide efforts, and in function, from design of physical space to education and outdoor activities.30
San Francisco, for example, has supported the creation of more than one hundred street parks and parklets—small parcels of land repurposed as green community space. The city estimates that 98 percent of its residents live within a half mile of a park. The city and region’s public transit authority bought light-rail passenger cars with larger than standard windows to provide riders with better views of the Bay and other sights. Oslo has developed a 226-mile citywide trail system, along rivers and through forests, one of the most extensive city systems in the world. It has designated quiet areas in the city where outdoor, recreational, and cultural experiences are shielded from urban noise.
“The important thing,” says Beatley, “is to move cities closer to that immersive experience. And that means looking to many other ways to layer nature into cities. . . . It doesn’t necessarily have to sit in a large contiguous block of forest but could be the sum of many things.”31
When cities live and work with nature, instead of against her, they may lose the comforting sense of control that built solutions seem to offer. Depending on green infrastructure to suck up a certain amount of water or cool the air a certain number of degrees or on wetlands to protect property from a certain level of ocean surge may seem riskier than installing concrete sewers and barriers. But as the practice of renaturing urban space advances, its performance is becoming more reliable and predictable and, as we’ve seen, it offers important additional benefits that cities need.
In the climate-change era, however, the relationship that cities have with nature is not limited to figuring out how to obtain the full range of nature’s benefits. Cities are finding that nature, in the form of climate change and its risks, is altering how they can shape the future.