Studying climate change in Central Park

To a New Yorker, trying to explain the value of Central Park is a bit like trying to explain the value of the air we breathe, but a Columbia report makes a more practical list of the park's many benefits.

Scroll this
The park awaits the future we choose. (Photo: City Atlas)
The park awaits the future we choose. (Photo: City Atlas)

Cen­tral Park has pro­vided a serene escape from the busy streets of New York City since it opened in 1857. Now it is the sub­ject of a report from Colum­bia Uni­ver­sity, titled “Cli­mate Change Resilience Plan­ning,” and writ­ten for the Cen­tral Park Con­ser­vancy Insti­tute (the edu­ca­tional arm of the Cen­tral Park Con­ser­vancy).

The Columbia report dis­cusses the need to plan for cli­mate change in Cen­tral Park’s future, but begins by recognizing the ways in which the park provides irreplaceable benefits to the city and its peo­ple. To a New Yorker, trying to explain the value of Central Park is a bit like trying to explain the value of the air we breathe, but the report provides a practical list: Cen­tral Park encour­ages phys­i­cal activ­ity, serves as a des­ti­na­tion for edu­ca­tional school trips, and has been a very valu­able site for film, tele­vi­sion, and pho­tog­ra­phy. As the Smithsonian magazine reported in January, living near a park is known to provide profound, positive effects on physical and mental health. (Additional research about the psychological and civic value of parks has been covered in Atlantic Cities and the BBC, including the observation that moving near a park may make you more pervasively happy than winning the lottery.)

Efforts we make now to limit emissions to slow climate change, and to promote urban resilience with thoughtful park management, will have long rewards, as a healthy park clearly makes for a healthier city.

The park has a high degree of bio­di­ver­sity and according to the report, “Biodiversity plays an important role in climate change resilience. The more diverse an ecosystem is, the more likely it is to thrive, recover from disturbances and adapt to changes in a shorter time frame.” Continuing to enhance Central Park’s biodiversity will increase its resilience to climate change, and make it a suitable habitat for more plants and animals. For example, the park currently serves as a popular rest­ing place for many of the bird species that migrate along the East Coast.

The park's trees absorb CO2, buffer heavy rain, and remove pollutants. (Ph: Caroline Kim)
The park’s trees absorb CO2, buffer heavy rain, and remove pollutants. (Photo: Caroline Kim)

The three main ecosys­tems in the park are the urban for­est, the urban aquatic system (such as lakes), and the urban lawns, and the report details how climate change may affect each.

The park’s urban for­est ecosystem includes all the trees, many of which are in forested areas such as the Ram­ble and the North Woods. Older trees and seedlings will be put at the most risk by cli­mate change, while healthy young trees will have more abil­ity to adapt. A grad­ual increase in tem­per­a­ture might cause an increase in tree growth at first by speed­ing up pho­to­syn­the­sis. How­ever, cli­mate change will make heat waves more fre­quent and intense, and this will harm tree growth and decrease the avail­abil­ity of the water that trees need to live.

Cli­mate change will also cause an increase in pre­cip­i­ta­tion – in the win­ter, this will likely mean more ice or snow gath­er­ing on tree branches, which could cause branches to break off. The more fre­quent extreme weather events (as men­tioned ear­lier) could cause flood­ing, which can uproot trees.[pullquote align=”right”]Efforts we make now to limit CO2 emissions will have long rewards, as a healthy park makes for a healthier city. [/pullquote]

Trees also pre­vent soil ero­sion. As climate change brings increases in precipitation and extreme weather events, the presence of trees and other vegetation can reduce damage to the park and the city. Management of trees in the park is also important to promote climate resilience. Hur­ri­cane Sandy destroyed over one thou­sand trees in the park in 2012, and Sandy was one exam­ple of the kind of weather event that will likely become more com­mon as heat energy rises in our climate system.

The park’s urban aquatic ecosys­tem includes bod­ies of water, such as the Pond, the Lake, Tur­tle Pond, the Reser­voir, the Pool, and the Harlem Meer. Most of the aquatic species in these places are gen­er­ally suited to cer­tain tem­per­a­ture con­di­tions. Any species that won’t eas­ily adapt eas­ily to tem­per­a­ture changes, such as those that repro­duce less often, will be harmed.

Warmer tem­per­a­tures encour­age the unde­sired growth of algae. These tem­per­a­tures also make oxy­gen less dis­solv­able in the water, cre­at­ing “dead zones,” areas that can’t sup­port life due to low oxy­gen. A rise in pre­cip­i­ta­tion will increase the amount of runoff that ends up in lakes, and as runoff com­monly con­tains toxic sub­stances, this will reduce aquatic organ­ism pop­u­la­tions. More fre­quent heat waves will reduce pop­u­la­tions of zoo­plank­ton, which are an impor­tant part of aquatic food chains. Heat waves will espe­cially affect shal­low lakes and are likely to harm the fish and other ver­te­brate species in them.

The Sheep Meadow, the Great Lawn, and the North Meadow are all part of the park’s urban lawns ecosys­tem. Warmer tem­per­a­tures will boost the growth of lawns at first, as in the for­est ecosys­tem. How­ever, this higher growth rate together with the increased rain­fall will make the soil more acidic, so keep­ing the soil at a usable pH will become dif­fi­cult. Changes in the win­ter cli­mate may make the soil less able to store inor­ganic nitro­gen (com­pounds of nitro­gen that are not nat­u­rally found in organ­isms). This may allow the nitro­gen to pol­lute nearby water, mak­ing the water unsafe for pond life.

Fre­quent heat waves may cause peri­ods with little rain­fall in the sum­mer, dur­ing which the soil may become drier and harder and the grass will die back. Such droughts could also harm the microbes and fungi – these are impor­tant to the soil because they act as decom­posers, break­ing down organic mat­ter into usable nutrients.

Central Park can test one's wits with outdoor chess. (City Atlas)
Central Park provides space for many kinds of public interaction. (City Atlas)

The fact that Cen­tral Park, such a famous and well-loved part of the city, will be impacted by the growing effects of cli­mate change may moti­vate New York­ers to respond to a global challenge and work toward real solu­tions. In addi­tion, data about Cen­tral Park in a high-CO2 atmosphere hints at how so many dif­fer­ent ani­mals, forests, lakes, rivers, fields, and cities elsewhere in the world will be equally dis­rupted by our new conditions.

While cli­mate change is an immense global prob­lem, its effects will com­monly be felt at the small­est level, within parks, fam­i­lies, and our city. But with Central Park as our guide, New York City and its residents may lead towards designing a livable and healthy future for everyone.