For the first time this year, more people will live in cities than anywhere else on the planet. Speaking to a gathering of urban planners at the World Bank in Washington, New York City mayor Michael Bloomberg urged policy makers and the public to confront the challenges of urban life with a new vision.

More than eight million people live in New York City. America's largest metropolis will add another million residents by 2025. Mayor Michael Bloomberg told the World Bank audience that such explosive urban growth in New York and elsewhere around the globe creates enormous social, economic and political pressures. "And as citizens of the world, our duties are great, but so are the opportunities I think for building a more secure and prosperous world for everyone: where ending illiteracy or hunger, or stopping AIDS, or cleaning the air, or deterring corruption are things that really are within our control."

Bloomberg took office shortly after the terrorist attack on New York City on September 11th 2001. It was predicted then that people and businesses would flee New York and that the city's economy would collapse.

That didn't happen. Bloomberg says in the last six years, New York has lowered its crime rate, reduced poverty, improved schools, banned smoking in public places and taken steps to address global climate change. "If you want to know the biggest difference between New York and the cities that never recovered from job losses of the 1970s in America, I have one word for you: immigrants."

Today 37 percent of New Yorkers - more than three million people - are foreign-born, and more than 70 percent of them have come to New York since 1980. "Their ambition, hard work and entrepreneurial drive continues to bring dynamic new life to our economy and a fresh new spirit to our city."

Bloomberg says global capital is also helping boost the city's economy. "We finance development around the world, and you see today other countries are doing the same thing in New York."

Bloomberg says the city has moved to find innovative ideas beyond its borders. He says to address local poverty issues the city has looked for solutions in the third world. "New York has recently become the first U.S. city to adopt - on a trial basis - the kind of 'conditional cash transfers' that have been successful in Mexico, Turkey, Brazil and other developing nations."

The idea is to pay students to stay in school, to stay in their jobs and to help them break the cycle of poverty. Bloomberg expects the investment to pay off. "Nearly 5,000 families are already enrolled in what we call 'Opportunity NYC.' This program is currently privately funded. And, if it becomes the success we hope it will, then we will invest public dollars in it."

Bloomberg says it is not just money that helps a city prosper in these challenging times, but learning how to do more with less. He says managers need solid research and rigorous analysis to help them decide how to allocate scarce resources. He says that means governing by "what is right in terms of the science of running that agency. And that is true whether it is a social service agency, whether it is helping the arts or whether it is reducing crime."

Political independence and a willingness to fight vested interests have paid off for New York, Bloomberg said. He noted how New York's anti-smoking campaign - fought vigorously by many of the city's bar and restaurant owners - has helped reduce adult smoking by 20 percent and teen smoking by 52 percent. "And, that translates into a quarter-million fewer smokers, untold millions, short and long term in saved dollars in health care costs and even more importantly, saved lives."

Bloomberg urged the World Bank experts to follow New York's lead in addressing the urban challenges of the 21st century: "Enlarging the realm of human happiness and opening up new vistas of human possibility. When we talk about building better cities in our world, that's truly what's at stake."

Bloomberg said he expects New York to continue to build on its success, success, he told the World Bank audience, that is within the reach of cities around the world.