• Ethan Olson

The Role of the Landscape Architect in the Fight against Climate Change

BY ETHAN OLSON


Hunter's Point South Waterfront Park protects coastal communities against floods.


Landscape architecture is a curious field. For one, it is relatively obscure: a specialty within a greater world of “architecture” that is better known for its triumphs of built forms — monuments, palaces, libraries, etc. — than its more subtle, low-striding landscaped counterparts of parks, courtyards, and gardens. In contrast to the design of buildings, the design of open space, an umbrella term for all of the territory falling outside the walls of a building and thus within the purview of landscape architects, is a process far less documented within the spheres of public culture. Ask a person to name an architect, and they’ll likely be able to list at least a few: Frank Lloyd Wright, Zaha Hadid, or Le Corbusier, perhaps. But ask any normal person to identify a single landscape architect, and you’ll likely find much less success.


When it comes to the question of grappling with a changing climate however, the profession of landscape architecture is uniquely poised to handle the challenge. Whereas normal architecture has the capacity to help mitigate climate change through improvements in energy efficiency and construction materials to lower emissions, landscape architecture has the capacity to not only mitigate but adapt to climate change in a diverse and colorful myriad of ways unparalleled by most other fields.


Mitigation

When it comes to climate change mitigation, landscape architects have a wide range of strategies at their disposal. Mitigation, which refers to anything that slows down global warming by reducing the concentration of greenhouse gasses within the atmosphere, is something that can take many forms at every social scale, from individual actions like eating less meat to national legislation that provides funding for public transportation systems.


The primary way in which landscape architects can mitigate climate change is by continuing to do what they’re perhaps known best for: planting plants. Every pound of carbon stored within the leaves, stems, and trunks of a photosynthetic organism is one pound less of carbon occupying space in the atmosphere. This fact is simple, which partially explains why schemes such as tree-planting initiatives are so popular with the general public. However, the type of plants selected for a certain environment, the way they are arranged, and how they are maintained are vital elements in determining the actual carbon sequestration potential of different landscapes.


Consider initiatives that aim to plant a set number of trees within a certain period of time, or a pledge by a company to offset some emissions by planting a sapling for every product sold. When done through methods that respect ecological science, these schemes are fantastic ways to restore pieces of land degraded by human activities. However, in some scenarios, tree planting schemes can actually have a net positive effect on the level of greenhouse gas in the atmosphere. Some “reforestation” efforts are more truly “tree farming” businesses that plant one singular species of sapling across a massive swath of territory. The trees are often arranged in repetitive rows too narrow to foster a healthy understory of shrubs, groundcovers, and annuals that promotes the biodiversity of a real forest, and which sequesters far more carbon in its larger volume of vegetation and richer soil. Sometimes, the seeds or saplings that are planted — and counted as one individual tree for a company’s public relations team to boast about on social media — never sprout or die after a few months. Trees that do succeed in reaching maturity, meanwhile, are not always wisely placed. Many reforestation efforts are taking place on rangelands that are not only some of the most biodiverse ecosystems on the planet, but capable of sequestering more carbon than the forest ecosystems that are replacing them, thanks in part to the efficient turnover of dead organic matter into these landscapes’ soils.

As such, choosing a proper catalog of plants, planting them wisely, and considering the existing conditions of the site are an important step landscape architects must take when addressing the realities of climate change. If a designer of a park wants to make the claim that they are helping fight climate change by planting a few trees, they must be able to prove that these trees will be able to sequester carbon efficiently over the course of their lifetime; they will need to stop staring at the leaves, and begin looking at the roots of the issue. Landscape architects will need to become sensitive to ecology, particularly across wide scales or within critically sensitive zones, and respect it as much as the other facets of their work.


Adaptation

Saying that climate change is inevitable is inaccurate: it is already here. Some amount of global warming is already locked in by the amount of greenhouse gasses emitted over the course of the past century. Because of this, consequences such as sea level rise, droughts, and heat waves will increase over the coming decades.


Landscape architects can help communities adapt to these changes in the following ways:


Water


Managing water effectively will be a key challenge in a warming world. Coastal flooding — made more common by sea level rise and the increasing intensity of extreme weather events — will threaten communities across the world with the inundation of roads, homes, and water utility infrastructure. To adapt to this risk, landscape architects such as Kate Orff of Scape Studio are creating ingenuitive designs along urban waterfronts that are part infrastructure, part public space, and part wild habitat. Orff’s designs include an oyster reef that filters water while simultaneously serving as a bulwark against storm surges, a regional plan for the Louisiana coast that seeks to restore the balance between freshwater and saltwater in coastal basins, and a proposal to turn a collapsed pier into “a public learning laboratory for intertidal habitat and harbor ecology.”


“Oyster-tecture envisions an active oyster reef that diversifies aqueous marine life and recreational potential in the New York Harbor.” — Scape Studio


These projects demonstrate the unique role biophilic design can play in protecting coastal communities against flooding, and offer an exciting alternative to historical attempts at managing similar challenges with concrete, asphalt, and steel.


It isn’t just coastal flooding that will increase with climate change; freshwater flooding from extreme precipitation events will also become more common and severe. Landscape architects can play a key role in managing these threats in a variety of ways: by expanding the absorbent capacity of riverfronts through riparian habitats, by making landscaped surfaces more permeable to discourage the accumulation of rainwater, and creating other types of green infrastructure — such as bioswales — to manage stormwater runoff.


Heat


Heat is another growing threat posed by the warming of the planet’s average surface temperature. Heat waves will become more common and more prolonged as climate change continues, creating risk for communities who are not used to extreme heat (such as many European cities that were not equipped for the deadly heat wave that struck last summer, killing thousands); communities that are already struggling in extreme climates (such as desert cities like Phoenix, Arizona, which is predicted to go from having 51 days per year that are above 100 degrees Fahrenheit to 125 days per year that are above 100 degrees Fahrenheit by the end of this century on our current emissions trajectory); and vulnerable subsections of communities that are less capable of handling or finding refuge from the high temperatures, such as the poor, homeless, and elderly.


As the leading cause of weather-related deaths in the United States, landscape architects have the potential to design life-saving interventions to reduce the threat of extreme heat, particularly within urban environments. It is well-known amongst many climate-conscious individuals that vegetation helps reduce the effects of the urban heat island effect — or the increased temperatures of cities relative to other landscapes due to their high concentration of heat-absorptive surfaces like pavement, roads, and buildings — by creating shade, reflecting more sunlight, trapping less thermal energy, and releasing water into the air through transpiration. For example, on some summer days in New York City, Central Park West is 30 degrees cooler than streets in East Harlem, which host unimpressive tree canopies thanks in part due to years of racially-motivated disinvestment. As the designers of parks, streetsides, plazas, and other public spaces, landscape architects can play a key role in greening our cities to not only make them more resilient to a warming world, but more equitable in how we adapt to one.


Wildlife


Measuring changes in biodiversity comprehensively and accurately is difficult, but the evidence regarding climate change’s effect on global wildlife populations is clear and grim. Massive losses in biodiversity due to changing temperatures, new rainfall patterns, and extreme weather events — coupled with human activities that convert biodiverse landscapes into monoculture plantations, suburbs, or industrial sites that emit pollutants into the remaining natural ecosystems — mean that countless species will migrate and seek refuge in new locations. Landscape architects must be sensitive to this crisis, and strive for designs that incorporate vulnerable species and the ecological infrastructure to support them. Two wonderful examples of this are Memorial Park in Houston, Texas, and Freshkills Park on New York City’s Staten Island.


The new masterplan for Memorial Park, created by Nelson Byrd Woltz Landscape Architects, responds to two extreme weather events that wreaked havoc on the sprawling 1500 acre site — Hurricane Ike and a blistering drought — with a holistic approach that places ecology at the heart of its design. It includes interventions to manage invasive species, restore wetlands, and enhance wildlife connectivity, all while improving access by the general public for recreational use.


Memorial Park’s masterplan was inspired by a design logic that came from a year of ecological research.


Freshkills meanwhile, is located on what used to be a massive landfill that received as much as 29,000 tons of trash per day, with its last barge of garbage arriving on March 22, 2001. Since then, the site has transformed into an actively evolving oasis of flora and fauna, with creeks, wetlands, and meadows creating a dynamic mosaic of life across the site. The transition is a part of the process masterplanned by the firm James Corner Field Operations, who reimagined the polluted wasteland as a place with the potential to return hundreds of acres of New York City land back to biodiverse green space. Initial interventions were small. Instead of racing in to install roads and plant thousands of saplings in a toxic environment, the landscape architects let ecological processes do much of the work to naturally restore the health of the land. From there, as the soil health has improved thanks to organisms like lichen, plants have steadily been reintroduced, starting with grasses and now trees and shrubs, all planted in careful consideration of the site’s residual excretions of waste pollutants. As described by Robert Sullivan in The New York Times, “If Frederick Law Olmsted’s Central Park was the work of a static, pastoral painter, then Mr. Corner and his team were less artists than restoration biologists, jump-starting a framework and leaving the ecology of the site itself to finish things up.”


The Freshkills masterplan promises to transform a toxic site into a vast sanctuary for wildlife.


Both of these parks show how vast amounts of land — even in close proximity to urban centers — can be revitalized as resilient havens for wildlife. Although their massive scale is rare for most landscape architecture projects, their attention to the ecology of the land and its potential for fostering biodiversity is inspirational for all projects that aim to offset the impacts of climate change on vulnerable species.


Conclusion

In a world threatened by climate change, it is easy to assume that new technologies, flashy infrastructure, and higher seawalls are the most effective way to mitigate and adapt. But landscape architects continue to prove that this is often not the case. Returning to the most primal existing system there is — the land — for answers to our modern challenges offers an approach that decouples ourselves from a reliance on the products of industry and extraction. It is one that promises to not only address the crisis at hand, but to help grow our communities, in tandem with the shrubs and the trees and the grasses and the flowers and the ferns planted within them, into resilient places of prosperity and enchantment.


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