As cities around the world experience the effects of urbanization and increased density, how and where we provide green space to urban dwellers becomes more important. Proximity to green spaces such as parks and biking trails helps to promote physical and mental health, and should be shared equally amongst urban communities. However, like many public goods, new green space can create higher demand for housing in areas nearby, driving up living costs and displacing low-income groups that have been there for decades.

This phenomenon is known as eco-gentrification, and it leads to a situation where only the relatively wealthy benefit from the designation of new urban green spaces. To explore this phenomenon further, I and professor Katie Black of Kenyon College looked into New York’s High Line as a case study. The park was created on an abandoned rail line in the Chelsea neighborhood on the West Side of Manhattan. Known originally as the West Side Elevated Line, the railway opened in 1933 and was used primarily by the National Biscuit Company—better known as Nabisco—whose warehouse is now the home of the popular Chelsea Market, at the tracks’ southern end.

The railway was operational until the early 1980s, when the rise of trucking depressed rail use, and the line ultimately fell to disrepair. In 1999, two Chelsea residents formed the Friends of the High Line, a nonprofit group aiming to conserve the structure and repurpose it as a neighborhood amenity, culminating in a proposal to convert the existing structure into an elevated green space. The High Line opened in three sections between 2009 and 2014, and now spans nearly a mile and a half from Gansevoort to 34th Street.

The High Line, pre-development. Credit: Getty Images

Our paper set out to empirically gauge the impact of the High Line’s introduction on residential property values, in the context to the overarching social issue of eco-gentrification. We used a regression analysis in order to understand the varying premiums associated with the introduction of green space on home prices by delineating three “buffer zones” to measure the increase on property value by distance. Through our regression analysis, we found that homes within 0.1 miles of the High Line rose in value 35.3 percent more than homes in the range of 0.1–0.4 miles away. In other words, the home price premium associated with green space proximity decreases as distance from the High Line increases.

Allocating green space without displacing the long-term, low-income residents of an area is an important consideration for policy makers as they seek to balance the positive effects of green space allocation and the negative affects of eco-gentrification. In their book Just Green Enough: Urban Development and Environmental Gentrification, researchers Winifred Curran and Trina Hamilton pose their “just green enough” theory, examining how an area can become “too green” and thereby exacerbate the gentrification process. Just green enough theory focuses on social justice and allowing communities to design their own environmental initiatives, with keeping the local population intact as an explicit goal.

It aims to uncouple urban greening projects from the telltale markers of gentrification like opulent waterfronts and luxury real estate development. Quality-of-life improvements generated as a result of urban greening initiatives should be enjoyed by the existing residents of a neighborhood rather than pandering to the entry of wealthier, often whiter, households. As our paper shows, neglecting to make this goal an explicit outcome can lead to excessive gentrification as an unintended consequence.

The stark increase in property values resulting from the High Line confirms the inequitable impact of the walkway’s introduction. This reinforces eco-gentrification models in which green space access is only affordable to the wealthy, leaving poor communities bearing the weight of environmental disamenities. Furthermore, lack of green space reinforces the urban heat island effect, causing low income areas to experience disproportionately higher temperatures and worse air quality than their wealthier counterparts.

For these reasons, cities must take a more critical and community-centered approach to greening initiatives. Too often, as was the case with the High Line, private funding and planning lends itself to private interests that do not focus on the public which the good is intended to serve. The High Line is a mark of success for real estate developers and New York’s tourism industry, but it has also contributed to rising inequity among New York’s residents. The affordability of accessible green space should be a primary issue in the future for urban planners, and the retention of an area’s existing residents must be an explicit goal of greening projects in order to avoid the pitfalls of eco-gentrification.