MAKING CITIES WORK

GUARDIAN, UK Jaime Lerner rarely leaves home without his little black book. In between meetings with Russian senators, European diplomats, Korean politicians or Brazilian governors, the 70-year-old architect and urban planner opens the notebook and scribbles down his latest ideas.

Inside, there are sketches of the "portable street", a plan to transform deserted, rundown city centers into bustling communities. There are blueprints for the Dock-Dock, a tiny, futuristic automobile intended to cut congestion and pollution levels. And there are rap lyrics.

"It's possible, it's possible! You can do it! You can do it," reads the most recent, entitled The Sustainable Song. "Make the transition. Cut carbon emissions!"

Leaf through the notebook and it is easy to get a sense of the audacious and often eccentric thinking that has made him a hero in his native Brazil and a reference point for architects and city planners the world over. He is celebrated as the mayor who oversaw the once-unthinkable transformation of his hometown, Curitiba, turning a grimy, congested state capital into an economically viable example of green living and social responsibility. . .

By the mid-1960s, the population of Curitiba had burgeoned to nearly 500,000 and the problems that all large cities face were starting to appear. Frustrated by the responses of the authorities, Lerner and a group of young, idealistic architects and engineers began to set out their own designs for the city's future. . .

In contrast, Lerner's master plan for the city involved a mix of affordable, integrated transport as well as social and environmental program that would help break down social divisions and bring new life to the capital of Paraná state. In 1971, aged just 33, Lerner was "appointed" mayor by the military regime that ruled Brazil between 1964 and 1985. The Lerner revolution, which would later be replicated in cities from Colombia and Cuba to Russia, began.

"The city of Curitiba became a reference for doing exactly the opposite of what other cities were doing," he says. "Other cities were building big bridges and freeways, and we were making pedestrian streets. Many cities were building metro systems, and we started our own transport system.". . .

In 1988 came Lerner's masterpiece , the Rede Integrada de Transporte, or integrated transport system. The network - later reproduced in Bogotá, Los Angeles and Panama City - involved the construction of futuristic-style "tubos", tube-like streetside bus shelters from which people could travel anywhere in the city for a flat fare. The RIT was, in effect, a low-budget overland subway.

Then there were the recycling projects. Under Lerner, Curitiba began a pioneering project, exchanging food for separated rubbish with the poor in the favelas (shanty towns) that surrounded the city. "Today, Curitiba has the highest level of rubbish separation in the world," Lerner points out with pride. . .

The signs of Lerner's urban revolution are everywhere: in the once-abandoned quarries and landfill sites that have become parks and recreation areas; in the Lighthouses of Knowledge, educational centers where the city's youth can study and socialize free of charge; in the cultural centers and theatres; and even in the signs hanging from car garages, proudly proclaiming how many tires they have recycled since the year began.

Curitiba is not perfect, as the wooden shanties near the airport and the rising murder rate indicate, but it is a radically different city from most others in the continent. The city's GDP is the fourth highest among Brazil's cities, behind only Sao Paulo, Rio de Janeiro and the capital, Brasília. Curitiba also boasts some of the countries lowest illiteracy and unemployment rates. . .

Lerner speaks of his hopes for the world's cities with an evangelical passion. All cities are capable of solving problems, he believes, be they the slums of Rio de Janeiro or Caracas or the congestion of London and Paris. . .

Lerner also believes that urban planning can be a key weapon against global warming and climate change. "As I'm a descendent of Jews, I have some commandments that we need to follow," he says. "First commandment: use your car less. Second commandment: separate your rubbish. Third: live near to your work, or work near your home. It needs to be about life, work and movement being all together."

The rest, he says, is a question of simplicity. "One of the things I have learned is that we have to be committed to simplicity. There is no need to be scared of simplicity. And we can't want to have all the answers in the world. . .