 New York City's dense population and low automobile dependence help make New York among the most energy efficient in the United States.The city's greenhouse gas emission levels are relatively low when measured per capita, at 7.1 metric tons per person, below San Francisco, at 11.2 metric tons, and the national average, at 24.5.New Yorkers are collectively responsible for one percent of the nation's total greenhouse gas emissions, though comprise 2.7% of the nation's population.