The classification of climatic zones generally relies on geographic conditions of the area. This is because the location and its environment play a major role in the determination of its climate. In lieu of this, New York City has always been classified as a humid continental climatic zone. However, climate change, human activities and excessive use of fossil fuel have led to its re-classification as humid subtropical climate zone as per National Climate Assessment of USA.
To be classified as humid subtropical climate zone, it requires for the summer temperature to average above 72 degrees Fahrenheit — which New York’s have had since 1927 — and for winter temperatures to stay above 27 degrees Fahrenheit, on average. The city has met that requirement for the last five years. And the winters are only getting warmer each year.
Impact of rising temperatures in New York
Change in Biodiversity
Change in climatic conditions lead to change in biodiversity. According to faculty at Urban Horticulture Institute at Cornell University, many varieties of southern oak are moving north with increasing temperatures for its suitability to colder climate. But native birch trees and sugar maples are starting to have trouble because of summer heat and drought. This may eventually make them less prevalent in near future.
Trees that are native to warmer climates of Southeast Asia, India and parts of the Central and South Pacific such as Crepe myrtles are taking root in New York. Until recently, crepe myrtles in New York City would grow no larger than a shrub; gardeners would cut them down to the root for winter. Now the Brooklyn Botanic Garden grows several varieties year-round, and some have grown into 20-foot trees. They can be found throughout the city and the northern suburbs.
The botanic garden also grows the endangered monkey puzzle tree, from South America, outdoors in pots, year-round, whereas it used to only survive inside the conservatory.
Prevalence of Invasive Weeds
It has been observed that the weeds that were a minor problem earlier has started taking up lot more prevalence with change in biodiversity and climate. In fact, Japanese knotweed and porcelain berry that are known to be fast-growing weeds that attack trees and bushes, and which thrive in the warmer climate have taken up the botanical gardens and Central Park in NYC, increasing the work of gardeners’ manifold.
Bugs and pests that used to die off in winter are now surviving and have the chance to multiply. For instance, the hemlock woolly adelgid is a bug that attacks hemlock trees, native to New York area for thousands of years. Hemlocks provide cool, shaded areas north of the city which is favoured by black bears and migrating birds. Once the adelgids hit these trees, they cannot survive.
Climate change has always been seen as a phenomena of the future. A phenomenon, that will affect the future population far from now. However, these observations are contradictory to the belief. It is high time for us to understand that Climate change is real and it is already here and we need to take steps to combat it now.