Part I: Understanding Green Infrastructure

We live, to paraphrase Madonna’s 1984 song, “in a material world.” The substrates that make up our world are mixed, strapped together, and layered in increasingly complex ways. Highway ‘flyovers’ arch above our roads; a vasculature of subways and sewerage snake below the streets and between the pilings that keep our buildings up; and a canopy of antennae on rooftops allow us to access information on our mobile phones. In recent years, the term infrastructure has been persistently applied to material fabrications as a way to describe the political ambition of building the physical foundations that allow societies to flourish.

It appears on the agenda of both the Left and the Right: Keynesian economists argued, in the wake of the 2008 ‘Great Recession’, that government-led infrastructure projects would ‘build back’ economic stability; more recently, the term has been deployed as a central (if largely unfulfilled) promise in the campaigns of right-wing populists. This ‘infrastructural turn’ has come to mean far more than just physical systems, like roads and bridges. In politics, mentions of infrastructure can sound like balm for ailing societies, and a nostalgic way of conjuring up times when things ‘worked better’. In academia, an examination of ‘infrastructures’ may refer to the analysis of networks, including those with a more-than-human bent in which humans are intertwined with the ecological, cultural, and even computational systems swirling around them. To many, infrastructures should always be in the plural form, deployed to describe the network of invisible forces that shape and govern human behaviour and interactions within the built environment.

Infrastructural projects defined by wires, cables, concrete, and welding inevitably play into masculinist themes of strength, dominance, and the conquest of nature; and project instigators often come from the field of engineering and the male-dominated building trades. However, an expanded view of infrastructure has recently taken hold, in which the term also describes networks that provide support, care, and learning. Particularly in the aftermath of the Covid pandemic, applying the term infrastructure to systems based on care helped to illuminate gaps in the provision of health services, elder care, and psychological support. When examining infrastructure beyond the material—the pylons-and-pillars notions—it’s perhaps wise to start with something definitional. If infrastructure can be anything, what is it not?

If infrastructure can be anything, what is it not?

Infrastructure is a term that has been so bandied about that, like ‘resilience’ in the wake of natural disasters, its meaning is at risk of evaporating. The sociologist Susan Leigh Star described infrastructure as “a system of substrates” evoking pipes, transistors, and railroad ties, but also making room for other support systems that allow our daily lives to progress unimpeded. Star’s best-known work highlights how infrastructures, which are typically invisible and taken for granted when properly functioning, become visible and problematic when they break down. Infrastructural failure, like the collapse of the Morandi Bridge in Genoa or the breakdown of Atlanta’s ageing sewers after intense rainfall (or, for that matter, health systems during Covid), highlights these systems’ intricate and interconnected nature, as well as the complex social, political, and technical factors that shape their operation. Star notes that “even when there are back-up mechanisms or procedures, their existence further highlights the now-visible infrastructure.” Infrastructural failures expose the fragility of systems we take for granted, revealing interdependencies. These breakdowns force us to confront the hidden vulnerabilities of the technologies that underpin society. To ensure reliability and stability, the goal is to build systems that are invisible and run in the background.

While traditional infrastructures have helped facilitate the movement of goods, people, and information; there are also infrastructures that have been called upon to mitigate the negative effects of increased travel and trade. As rivers, dams, and locks were built on major rivers, fish could no longer get upstream: enter the ‘fish ladder’. As spreading urbanisation created more and more impervious surfaces that collect rainwater, civil engineers built drains and subterranean canals to channel that water away from properties. These technological solutions have helped to return fish to their spawning grounds and prevent flooding, but they often fail to balance environmental systems, necessitating more fixes in the future. The creation of these regenerative infrastructures is in the vein of the ‘promethean promise’. In this animating tale of human achievement, humankind can always ‘snatch fire from heaven’, and hammer our way out of predicaments, restoring balance to ecosystems and smoothing the transition between different stages of development. This has fed into the gospel of innovation, but innovation, in and of itself, seems unlikely to counter the largest issue facing humankind: climate change.

Projects aiming to counter climate change with all-encompassing solutions, have frequently been met with dismissal.

Projects aiming to counter climate change with all-encompassing solutions, have frequently been met with dismissal. The idea that a planetary-level fix exists smacks of geoengineering which, in turn, reminds people of previous missteps when ‘miracle technology’ went wrong, such as birth defects produced by medicines for pregnant women, fire-retardant household products made from asbestos, and the contamination of groundwater from the overuse of chemical fertilisers. Some solutions that would remove atmospheric carbon dioxide, block solar radiation, or reduce ocean acidification appear promising, but they are unlikely to be enough in and of themselves, and their potential to generate unintended outcomes (as dramatised in sci-fi films like Snowpiercer) are myriad. When a recent article on the front page of the New York Times asked if we could “engineer our way out of climate change?” comments poured in, citing these efforts as a distraction, incapable of significantly lowering our planet’s rising temperatures. When pushing for new climate mitigation infrastructures, activists have encouraged engineers to think of many small changes, rather than one big fix. Local-level improvements can help us to live in a warmer world with severe, often unpredictable, weather. That’s not to say that we shouldn't think big, but the development of big attention-grabbing projects shouldn’t come at the expense of modestly-scaled, on-the-ground efforts. Advocating for infrastructure that mitigates climate change is an acknowledgement that human actions have irrevocably changed the planet, and that it must be humans who set it back on track. An infrastructural frame admits our desire to change the world, but suggests that we do it using processes from nature, instead of fighting against them.

Green Infrastructure

Today we see a new emphasis on ‘green’ infrastructure projects, developed in contrast to traditional infrastructures, which are often described as ‘grey’. This reflects the imperative of mitigating climate change, and a shifting perspective on urbanisation. The notion that the built environment is distinct from ‘pristine’ wilderness areas is being challenged, and dense urban settlement—once thought of as antithetical to environmental goals—is increasingly being recognised as one of the most carbon-neutral ways for humans to live. In part, this is because the clustering of people in cities allows for the preservation of lands that would previously have been used for sprawling suburban developments. Rather than viewing nature as something detached from cities (the Romantic idea of an untouched wilderness ‘out there’), green infrastructures embrace the concept of creating and nurturing ‘second natures’ that integrate ecological processes into the fabric of urban spaces.

This approach recognizes that cities themselves are part of complex socio-ecological systems, and that bringing nature closer through the creation of urban wetlands and forests, and green roofs can provide cooling, animal habitat, and protection from erosion and flooding. Creating green infrastructure is often spoken of in tandem with the provision of ecosystem services, a kind of self-replenishing green assets that help to sustain flora and fauna (humans included). Environmental features become green infrastructure when they are strategically integrated into the built environment. Dark corridors that act as pathways for bats and other light-sensitive creatures strategically placed to connect. When random dark parks are scattered throughout a brightly lit environment, they fall short, as far as the bats are concerned, and are not infrastructural.

Infrastructure that is green, and, often, blue (water-based), pushes back against ideas of human exceptionalism by situating our species within a broader continuum of life.

Infrastructure that is green, and, often, blue (water-based), pushes back against ideas of human exceptionalism by situating our species within a broader continuum of life. Green infrastructure helps to connect people living in the heavily managed built environment with the wider world of plants, and it provides opportunities to commune with other species; mitigating some of the downsides of density, the psychological stress of crowding, and the anomie of modern societies.

Green infrastructure is also deeply pragmatic, corridors and habitats within cities for plants, animals, and insects helps to maintain biodiversity and well-placed community gardens, urban forests, and wetlands can help offset the ‘heat island effect’, sponge up water from the severe storms (that have already started occurring more frequently as a result of climate change), and provide probiotic exposure to bacteria that can help prevent infections and allergies. Green spaces in the city also provide opportunities for ‘low carbon leisure’, gratifying activities outside of consumption. When done well, spaces of urbanised nature provide recreational, as well as spiritual, benefits.

Parks for the People: Green Space and Urban Cultures

If you are reading this and thinking, “green infrastructure, that sounds like parks.” You wouldn’t be wrong, but parks come in many stripes. Many of the well-manicured leisure spaces that are passed off as parklands are optically green but lacking in biodiversity. Their lawns are subject to frequent mowing, their shrubbery is ornamental, and their trees are severely trimmed back . Parks are, traditionally, places for people, whose leisure and comfort are paramount, and parks’ role in local ecosystems is secondary. Today, we see an expanding notion of what parks can, and should, do for the societies who build and maintain them, and for animal and plant habitat.

Parks provide recreational space, such as playing fields, but they also evoke pastoral visions of the countryside by incorporating winding paths and ‘naturalistic’ arrangements of trees and shrubbery. They bring bucolic landscapes close to city dwellers. Bucolic comes from the word shepherd, and one only needs to think of the idealised paintings of the early 19th century to see why this vision of the countryside was so appealing: strapping rosy-cheeked youth supervising grazing sheep presented a healthful alternative to the anaemic city kids of the era. In city parks, it was thought, children could grow strong like their country cousins.

For adults, parks presented the possibility of release from the overstimulation of city life Twisty pathways and ornamental lakes produced a a miniaturised version of healthy (and far larger) ecosystems from far outside the city limits. If the city was epitomised by crowds, hard edges , and the monotony of repeated forms, parks allowed those with leisure time to wander, think, and find themselves.

While parks were often celebrated as proof of civic leaders’ largess, with statuary around their perimeter and city crests moulded on their wrought iron gates, they were just as much the product of fear.

The growth of cities during the Industrial Revolution made old growth forest and swimable bodies of water inaccessible to city dwellers. In recompense for those lost acres of green, municipalities created close replicas: parks. These were often the leftovers of royal hunting estates or, in some cases, noxious land uses that had been pushed further out of the city by the growth of railroads and the advent of more streamlined production processes. Amsterdam’s Vondelpark (inaugurated in 1865), Paris’s Parc des Buttes-Chaumont and Brooklyn’s Prospect Park (both started in 1867) were all former quarries and brick-making yards. Their creation, in the mid-19th century, went hand-in-hand with the growth of municipal governments and the increased provision of services for citizens. While parks were often celebrated as proof of civic leaders’ largess, with statuary around their perimeter and city crests moulded on their wrought iron gates, they were just as much the product of fear. Especially in Continental Europe, where wealthy burghers had witnessed the French Revolution followed by the revolutions of 1848, there was a strong desire to improve the conditions of the working classes and thus keep uprisings at bay. Parks, with their winding paths and dispersed attractions, were subtly designed to undermine opportunities for mass gatherings and political rallies, but they were also created to alleviate mental and social pressures that were thought to kindle the revolutionary spirit.

Parks were designed as spaces for healthful leisure, often set up as salubrious alternatives to ale houses and gambling parlours (prime spots for social life in the 18th and early 19th centuries). Yet, many first-generation public parks were not designed with sport in mind, but with the idea that they would be used for strolling, deep conversations, and the appreciation of nature. They were spaces for moral uplift. Frederick Law Olmsted, the designer of Central Park, believed that exposure to natural scenery and open spaces could improve the condition of New York’s poorer residents. In 1858, as the park’s first stage was wrapping up, he wrote, “it is one great purpose of the Park to supply to the hundreds of thousands of tired workers, who have no opportunity to spend their summers in the country, a specimen of God’s handiwork”. The park was to be a ‘civilising force’, where naturalistic landscapes would impart lessons on good citizenship and uprightness. It even included a dairy, completed in 1871, a concession where families could buy snacks and subsidised milk. While tolerated at picnics today, alcohol has never been officially permitted in the park, and, in 2011 , smoking was banned in all of New York City’s parks.

After all, forested spaces play into deeper cultural sensibilities surrounding nature.

Despite the social mixing that occurred in large public parks, they were, at the outset, primarily the domain of the “swell set,” particularly on weekdays when others were at work. Central Park’s Mall was designed as an “an open-air hall of reception” and Hyde Park was so well known as a meeting place for the upper classes that in The Picture of Dorian Gray, Sibyl Vane’s brother, a sailor, begs off a stroll in the park, his clothing being “too shabby.” However, daytime social controls proved difficult to enforce at all times, and night closures were inconsistent. Newspaper reports from the 1890s describe “prostitutes, pickpockets, and tramps” as frequenters of Central Park’s Ramble , and London’s Hyde Park was known for dice games under cover of dense foliage. The fact that licentiousness abounded in spaces designed to instil restraint and abstinence is, perhaps, not surprising. After all, forested spaces play into deeper cultural sensibilities surrounding nature. In many pre-Christian European cultures, forests were where the fairies lived: they were semi-magical domains where people transformed, becoming one with their animal nature. In Shakespeare’s A Midsummer Night's Dream, young lovers enter Puck’s Forest only to succumb to lust and irrational behaviour. Public green spaces were meant to have an edifying, perhaps even pacifying role for the inhabitants of fast-growing cities, but they also provided a release valve, and their secluded nooks were some of the rare places where decorum could be dropped.

The non-human animals of parks have varied considerably. Many of the first greenbelts, such as Adelaide, Australia’s Parklands, contained grazing areas. Central Park’s Sheep Meadow was famously ‘mowed’ by its ovine inhabitants until 1934. However, other animals that one might expect to find in forests and meadows—especially predators like wolves, foxes, and bears—have been chased out. In the mid-20th century, when sheep were replaced by lawnmowers and herbicides, the insect, reptile, and avian life of parks also suffered. These losses were recognized by the burgeoning environmental movement of the 1960s. Since then, environmentalists have tried to ‘re-wild’ urban parks, often under the framing of biodiversity.

The Birds and the Bees: Planning for Urban Biodiversity

In the early 2000s beekeepers across Europe and North America noticed that their hives were being abandoned by worker bees, but still contained young broods, food stores, and a queen. This wasn’t entirely without precedent, but it was happening at a far larger scale than had ever been seen before. In 2007, following several dire reports, the phenomenon received a new name: colony collapse disorder. This alarming decline of honeybees had broader implications because they are critical for pollinating other plants, including cash crops like berries and melons. Scientists believe colony collapse disorder results from a combination of factors such as pathogens, poor nutrition, and pesticide exposure. Products applied as weed killers that were thought to only kill the few unlucky bees who wandered into their spray were reconsidered when it became clear that they accounted for larger-scale “chemical destruction of habitat”. Colony collapse became an environmental cause célèbre, and it highlighted the tension between outdoor spaces that appear green and truly biodiverse landscapes.

Colony collapse became an environmental cause célèbre, and it highlighted the tension between outdoor spaces that appear green and truly biodiverse landscapes.

To support healthy bee populations, green spaces need to provide diverse native flowering plants as food sources and nesting sites, like patches of uncultivated soil or bundles of hollow plant stems. People also need to cut back on spraying. In many cases, sites that were promoted as urbanised nature —such as parks, sport fields, and golf courses—were insufficiently wild for the tastes of bees and other animals. Indeed, many of these spaces were “ecologically impoverished” because of “high inputs of fertilisers, pesticides, and lawn mowing” and large swathes of impermeable surfaces. Using a metaphor from urban food insecurity, Australian researchers noted that sprawling suburbs and widespread herbicide use had turned landscapes across Melbourne into “food deserts” for bees. The city has since tried to remedy this by encouraging residents to plant their backyards with bee-friendly native flowers and woody shrubs, creating interconnected corridors across the metropolitan area.

These pollinator corridors have some parallels to the tunnels, culverts, and bridges that are used to help migrating animals safely cross roads and other infrastructure that disrupts their natural ecosystems. These connect archipelagos of habitat separated by wide fast-moving highways. The Wallis Annenberg Wildlife Crossing, scheduled for completion at the end of this year, creates a wide deck over a 10-lane interstate that cuts through the scrubby hills of Los Angeles’s suburbs. At 64 metres long and 50 metres wide, it will allow mule deer, coyotes, mountain lions and numerous other species to pass over an asphalt expanse where 300,000 cars speed by each day. Funding for the crossing came from 60% private donations, and 40% conservation funds from the state of California. Indeed, lawmakers seem to recognize that these corridors are important. U.S. President Joe Biden’s $1.2 trillion infrastructure bill set aside $350 million for infrastructure that helps protect animals through fencing, underpasses, and elevated crossings. Unfortunately, most of the money from the bill is likely to be spent on widening and maintaining roads, locking in automobility over public transport and necessitating the construction of far more safe crossings for animals. Still, the need to link discrete areas of habitat together has become a real issue, due in part to attention-grabbing campaigns that latched onto the star power of animals made famous on social media.

Just as endangered species campaigns have, historically, focused disproportionately on charismatic megafauna—like whales, elephants, and pandas—there is some concern that crossings, and other mitigation strategies, might focus too much on big and beloved animals, while less striking, but equally threatened, species go unnoticed. The fundability of the L.A. Wildlife Crossing was linked, in part, to its future use by big cats. The campaign often used images of mountain lions (also known as cougars), apex predators with muscular frames and long tails—the animal world’s runway models. One particular big cat, P-22, became the ‘poster puma’ for urban wildlife after a 2013 photo in National Geographic (taken after 15 months of putting up camera traps) captured him striding in front of the Hollywood sign. The cougar had lived for 12 years in the Santa Monica hills, near densely populated neighbourhoods and it was closely observed by the local wildlife department, and dozens of fan accounts across social media platforms. P-22 was known for skilfully crossing roads during periods of low traffic, but was eventually struck by a car, and, shortly thereafter, euthanised. While P-22, who died in 2022, was honoured with R.I.P murals and a tribute attended by thousands, advocating for animals with less star power has proven more difficult. Volunteers in California’s north, who help migrating newts cross a busy road in the hills above San Francisco, have had their funding requests for a newt-friendly culvert repeatedly turned down. These small, bumpy amphibians seem to be less of a draw than camera-friendly big cats. While the idea that large cougars might become roadkill has horrified the public, the death of smaller creatures on the roads is often treated as an inevitability. U.S. television segments, on both right-wing Fox News and the left-leaning Daily Show, have satirising amphibian wildlife corridors as “tiny turtle tunnels”, poking good natured fun, and directing real animus, at infrastructure intended for non-human use.

Efforts to improve biodiversity happen in an overheated media sphere with a fine line between productive actions and ‘greenwashing’.

Mitigating the harms of automobility and creating green connectors at a rate greater than new developments that have the capacity to destroy habitat, is a tall order. Efforts to improve biodiversity also happen in an overheated media sphere with a fine line between productive actions and ‘greenwashing’. After colony collapse became a major news item many architects and urban designers endeavoured to bring hives into their projects. In 2023, the chair of the London Beekeepers’ Association, described a rise in “trophy bees” nested at the top of office towers as a visible measure of corporate social responsibility. While the hives made for good photo ops, honeybees in major cities threatened to overwhelm “finite floral resources.” What was needed in urban centres wasn’t more honeybee hives, but boxes for bumblebees and ‘bee hotels’ for solitary bees. One can see more of these hotels, made from untreated wood, popping up in community gardens and parks. The redirection of efforts related to urban bees is indicative of the challenge faced by biodiversity initiatives. Animals are fickle and irrational actors in the built environment who neither follow wayfinding signage nor adhere to the desires of planners and engineers. Honeybees create a marketable commodity that can be enjoyed and shared, and big cats, a ‘keystone’ species, speak to the majesty of nature; advocating for smaller and less charismatic animals is the real test of a commitment to creating a more-than-human built environment. Most of all, biodiversity projects need to occur at large enough scales for them to attract plants and animals and to make an impact.

Read Part II: Understanding Green Infrastructure here.

Samuel Holleran is an interdisciplinary artist and writer. He has worked as an art director, researcher, and educator with civically-engaged design firms, universities, and nonprofits in the U.S., Australasia, and Europe. He is currently a Postdoctoral Research Fellow in Urban Design at RMIT University in Melbourne, Australia.

*The above text was commissioned in collaboration with Stavanger municipality’s project NEB-STAR — New European Bauhaus Stavanger. CAS and NEB-STAR have entered into a collaboration on a collection of texts that are part of CAS’ ongoing text series “Built Environments”. The series presents different approaches to urban development and different opinions on the design of urban landscapes. CAS has editorial freedom and editorial responsibility in this collaboration.