New York City is marking Earth Week by promoting an ambitious project to become the world's most sustainable metropolis.  The city is taking cues from countries around the world on how to achieve an environmentally friendly future.

Though it is often called "the concrete jungle," New York City is surprisingly eco-friendly.  The city boasts a massive and efficient public transit system, and it is located downhill from fresh water reserves, meaning that it takes little energy to pump clean water into the city.

However, city planners are anticipating that New York City will grow by another one million people by the year 2030 - to more than nine million inhabitants.  To deal with the population growth, Mayor Michael Bloomberg has introduced a series of eco-friendly initiatives to improve housing, transportation, energy, and air and water quality. Some of the initiatives in the so-called PlaNYC include planting one million new trees and building newer, cleaner power plants.

City officials also want to make New York a model of green living for the rest of the world.  An ongoing exhibit at the Museum of the City of New York shows New Yorkers how the initiatives can improve their everyday lives.

Sarah Henry is the museum's Deputy Director.

"We recognize that there are models elsewhere that are also pushing the envelope that New York needs to emulate," said Sarah Henry. "We really see this as a dialogue - a dialogue of New York's leadership in some areas and New York's ability to be responsive to models that are being created elsewhere."

One such model is the city of Songdo, South Korea.  The city is an international business center being developed on more than 600 hectares of reclaimed land.  Developers say that when it's completed, 40 percent of its footprint will be green space and all construction will use the most energy-efficient designs possible.

The Museum of the City of New York exhibit is drawing the attention of more than just New Yorkers.  On Earth Day this week, Anne Clair, a tourist from Belgium, said she was glad to find that America's biggest city is doing more to promote an environmentally-friendly future.  But she said there is still room for improvement.

"I found it surprising that you don't recycle a lot here," said Anne Clair. "For instance, when you go shopping in Belgium, we have to reuse bags."

Since PlanYC was introduced two years ago, New York has planted 200,000 trees and improved energy efficiency in dozens of buildings, helping to eliminate greenhouse gasses.

Sarah Henry of the Museum of the City of New York  says the city is looking to further reduce emissions  by looking to Bogota, Colombia.  That city's rapid transit program has made traveling by bus faster and cleaner, with dedicated lanes and multiple doors on busses that to allow passengers to get on and off more quickly, increasing efficiency.

"It's all designed to really facilitate peoples use of the buses, encourage their use of the buses and then move those buses quickly through dedicated lanes, so that the bus becomes a preferable system to driving your own car," she said.

This week, elected leaders in New York took their green efforts a step further by enacting laws and initiatives aimed at reducing energy consumption by requiring owners of thousands of older buildings to upgrade numerous energy consuming systems - from heaters to light bulbs.