The study was ordered by Mayor Michael Bloomberg to assess the city’s progress in reducing its greenhouse gas emissions by 30% by 2030.
“You have to have a real baseline or we’re just talking past each other as to what works and what doesn’t work — we won’t ever know whether we really made a difference,” Bloomberg said.
The study found that the buildings, subways, buses, cars and decomposition of waste in America’s most populous city produced a net emission of 58.3 million metric tons of greenhouse gases in 2005.
The US total came to 7.26 billion metric tons for that year.
Greenhouse gases, including carbon dioxide, methane and other gases, essentially trap energy from the sun, which warms the Earth’s surface and lower atmosphere. Many scientists believe human activity that increases those gases is contributing to global warming.
The Intergovernmental Panel on Climate Change, a United Nations network of 2,000 scientists, warned last week of possible catastrophes such as floods, disease, food shortages, species extinction and human suffering throughout the world.
The city has 2.7% of the US population — 8.2 million of 300 million — and the average New York city resident contributes less than a third of the emissions generated by a typical American. This is largely due to the popularity of the city’s mass transit system, which cuts down on car emissions, officials said.
The study found that the city’s focus on environmentally friendly initiatives — including alternative fuel vehicles, energy-efficient traffic lights and green buildings — appears to have helped stabilise emissions rates in recent years.