A new partnership aims to turn Central Park into an open-air laboratory for scientists studying the impact of climate change on the city.
Over the next three to five years, Central Park Conservancy, Yale School for the Environment and the Natural Areas Conservancy will fund a project to analyze 40 years of meticulously-kept park records. This trove includes the dates of lawn-mowing, when flower buds emerged each spring, and the measurements of the soil and tree canopy.
With this wealth of data, the scientists hope to attain a more detailed understanding of how the park has changed along with the climate. These revelations could show whether seasons are arriving early or late compared to the past and exactly which plants are thriving or not. Such information can help the city build new nature-based strategies for staving off the harms of climate change.
“Park land is very, very heavily used, and it is essential urban infrastructure,” said Betsy Smith, executive director of the non-profit Central Park Conservancy. “We can see what is happening with eroded landscapes or with tree canopy that's being affected by the storms, and wildlife is affected by it.”
Central Park is one of New York City’s playgrounds. More than half of New Yorkers visit city parks on a daily or weekly basis, according to a survey conducted by the U.S. Forest Service. Central Park’s 843 acres alone carry an estimated 40 million visitors every year. But green spaces are also the frontline for the city’s climate change transition — a place where trees can shelter people from heat waves or where researchers can learn how urban landscaping can mediate rainstorm flooding.
But as much as they mitigate these effects, urban parks have also suffered the ravages, too.
Last year when tropical storm Ida hit New York City, Central Park recorded more than 7 inches of rain. Staff spent nearly 3,000 hours to repair the damage, which included removing 23 trees and clearing flooded areas at Bethesda Fountain and park roadways. Parts of the park had to be closed to the public. It was the third tropical storm last year. Nearly two-thirds of that summer was rainy, and average monthly precipitation more than doubled, according to Central Park records.
Researchers believe these climate-driven damages and expenditures might be lessened or avoided by re-envisioning and leveraging the park's already existing “green infrastructure,” vegetation and trees. Project scientists are focusing on implementing natural forms of resiliency that can be adopted by other urban parks across the country. For example, planting different types of grass or shrubs could help soil hold more water and prevent flooding. Putting in more trees could thicken the canopy overhead, which intercepts water. That, in turn, has a cooling effect. On average, temperatures in green spaces are about 2 degrees Fahrenheit cooler than surrounding built environments.
“When the storm comes, the leaves themselves just capture a lot of precipitation,” said Brendan Shane, climate director at Trust for Public Land, a nonprofit that creates and protects parks. “Often the whole first quarter inch of rain never makes it to the ground.”
Those trees can also be instrumental in helping cities fight climate change by absorbing carbon. The forested areas of the city account for 25% of the total tree canopy, but store nearly 70% of the total carbon in all the trees across all five boroughs. They store four times as much carbon as street trees.
“Essentially, natural area forests are a high-carbon canopy type in urban areas,” lead project scientist Clara Pregitzer said.
At the end of the project, Pregitzer and the rest of the team hopes they can deliver tools in the form of data-rich maps that include tree species and their level of undergrowth, a study that specifically outlines the impacts of climate change on the park and an educational toolkit of interventions piloted to reduce those harms that can be used by other metropolitan area.
“We want to ensure that the landscape of the park continues to be vibrant and to thrive over time,” said Sarah Charlop-Powers, executive director, Natural Areas Conservancy.