Environment of New York City
The environment of New York City consists of many interwoven ecosystems as part of the New York–New Jersey Harbor Estuary. The climate of New York City shapes the environment with its cool, wet winters and hot, humid summers with plentiful rainfall all year round. As of 2020, New York City held 44,509 acres of urban tree canopy with 24% of its land covered in trees. As of 2020, the population of New York City numbered 8.8 million human beings. Climate. The climate of New York City features a humid subtropical variety, with parts of  the city transitioning into a humid continental climate, giving the city cool, wet winters and hot, humid summers with plentiful rainfall all year round. Ecosystems. As New York City grew into a city, the surrounding environment was altered by the growing demands of the human population. The ecosystem of New York City is consistently maintained to support a growing population in the city. In the last 400 years since the original ecological systems as researched by the Mannahatta Project, the growth and development of the New York City water supply system, the New York City waste management system, Transportation in  New York City, and Food and water in New York City has greatly altered the environment of New York City. In 2017, CCNY entomologist and Professor of Biology David Lohman discovered a new species of fly living in Central Park. The fly, "Themira lohmanus", has evolved to only breed on duck dung. Pollution. New York's population density has environmental pros and cons. It facilitates the highest mass transit use in the United States, but also concentrates pollution. Gasoline consumption in the city is at the rate the national average was in the 1920s, and greenhouse gas emissions are a  fraction of the national average, at 7.1 metric tons per person per year, below San Francisco, at 11.2 metric tons, and the national average, at 24.5 metric tons. New York City accounts for only 1% of United States greenhouse gas emissions while housing 2.7% of its population. In September 2012, New York was named the #1 "America's Dirtiest City," by a "Travel+Leisure" readership survey that rated the environmental quality of 35 prominent cities in the United States. Waste management. New York City's waste management system is a refuse removal system primarily run by the New York City Department  of Sanitation (DSNY). The department maintains the waste collection infrastructure and hires public and private contractors who remove the city's waste. This waste, created by New York City's population of more than eight million, can amount to more than ten thousand tons a day. Waste management has been an issue for New York City since its New Amsterdam days. As a 1657 New Amsterdam ordinance states, “It has been found, that within this City of Amsterdam in New Netherland many burghers and inhabitants throw their rubbish, filth, ashes, dead animals and suchlike things into the public streets to  the great inconvenience of the community". Horticulture. The Lenape peoples who inhabited the greater NYC area directly prior to European colonization cultivated the environment and land they lived on in New York City, historians believe they planted sunflowers at the edges of the maize fields alongside their villages. In addition, they relied on the many trees growing on what is now New York City for food, shelter, tool materials, fuel, and medicine. The typical Lenape house, called a longhouse, relied on the bending of the trunks taken from small trees to create a series of arches to serve as the  frame. The Lenape used the Zanthoxylum tree as medicine for toothaches because chewing on the leaves or bark creates a tingling, or numbing effect in the mouth.