NEW YORK - A global explosion of urban growth and the rise of the megacity could help resolve some of the world's deepest problems, from overpopulation to environmental devastation.

In an upbeat assessment, senior international business and political figures told a forum in New York that along with the obvious challenges, they saw huge opportunities in the rush to urbanization.

In 1800, just 3 percent of the world lived in urban areas. Today that figure has passed 50 percent and by 2050 it will likely reach 70 percent, with cities like New York, Mexico City, Moscow and Shanghai growing exponentially.

Mexican telecoms tycoon Carlos Slim, named by Forbes as the world's richest person, said that bringing people into urban areas is the only way for countries to cope with already inevitable population growth.

"If there were not big cities the service will not be affordable for the population," Slim told the panel at the annual meeting of the Clinton Global Initiative group.

Chinese Foreign Minister Yang Jiechi said his country is embracing the urban model with about 120 cities of more than a million people already on the map.

"Cities are very important for generating more GDP and to uplift the whole society," he said. "One percentage increase in urban population will mean a lot jobs, a lot of consumption and a lot of investment."

Of course, packing so many people into tight spaces brings equally big challenges.

"(It) will create a lot of problems as well, for instance: population pressure, environmental degradation and lack of social amenities," Yang said.

California's Lieutenant Governor Gavin Newsom described the "remarkable challenge to deal with ethnic, racial, religious diversity", and said what matters is "the human capital equation, not just the infrastructure".

Janette Sadik-Khan, transport commissioner for New York City, agreed, saying the Big Apple was attempting to make the city more pleasant as it prepares to accommodate an expected extra million people over the next 20 years, on top of the current 8.4 million population.

Agence France-Presse