BUENOS AIRES, Argentina - As the world scrambles to save dwindling resources and halt global warming, a long-scorned population is becoming the latest hope in the environmental battle.

The unsung heroes are the impoverished trash pickers who fill the streets of countless cities around the developing world, searching garbage for cardboard, plastic bags and other treasure that can be sold and recycled.

Every day, they rescue hundreds of thousands of tons of material from streets and trash dumps that get reprocessed into all kinds of products. That not only cuts back on the resources used by industries but also lightens the load on dumps that are quickly reaching capacity.

Despite their contributions, trash pickers have long suffered harassment from local governments and derision from neighbors, who often consider them vagrants or even criminals. Such attitudes, however, are changing, trash pickers said, and they're increasingly being seen as foot soldiers in the global warming battle.

"We're the only ones doing this work," said Cristian Robles, a trash picker who scours the Argentine capital of Buenos Aires for recyclables. "If we didn't do it, nobody else would."

As in Buenos Aires, government-run recycling programs are rare in most of the developing world, meaning valuable materials that could be reused end up rotting at local dumps if trash pickers don't get to them.

At an estimated 15 million people worldwide, trash pickers make up about 1 percent of the global urban population, and their impact is enormous, said Martin Medina, a U.S.-based waste management expert who wrote "The World's Scavengers," a book about the population.

Brazil, for example, claims the world's highest aluminum recycling rate, at nearly 90 percent - not because of official initiatives, but thanks to the country's estimated 500,000 trash pickers, Medina said. By comparison, only about half of the aluminum used in the United States is recycled, despite the proliferation of city-run recycling programs. In total, Brazilian trash pickers salvage about 33,000 tons of recyclables a day.

In Indonesia, the world's fourth most populous country, trash pickers recycle a third of all garbage, Medina said.

Trash pickers also reduce emissions of methane produced by rotting garbage in open-air dumps. That's no small contribution, considering methane wreaks more than 20 times the global-warming damage than carbon dioxide does.

"Environmentally, they're having a big effect," Medina said. "But they're not getting the support of governments. The entire system is based around economics, and people only turn to this when they have no other choice. Unemployment and layoffs are what's pushing many people into doing it."

That's the reality in a trash-strewn neighborhood of General San Martin, Argentina, a suburb of Buenos Aires, where almost all of the neighborhood's 60,000 residents earn their living through trash picking and recycling. Several said they started after Argentina's economy collapsed about seven years ago, pitching more than half of the country's population into poverty.

Argentina's economy has since bounced back, but poverty still plagues more than 20 percent of Argentines. As a result, many in the neighborhood still survive by recycling trash, which earns them about $220 a month. Medina estimates the activity generates about $170 million a year in Buenos Aires alone.

"It's always better to find other work, but there are no jobs, and we have to do what we know how to do," said 23-year-old Roberto Daniel Quiroz, who's been a trash picker since age 17.

Many of the recyclers in General San Martin suffer ailments related to the unsanitary work, such as infected cuts, gastrointestinal bacteria and conjunctivitis. They're also regularly harassed by police and city officials in Buenos Aires, where many trash pickers go to find the most valuable recyclables.

Adding to their woes, a local transport company recently stopped running a train that had hauled trash pickers and their finds between Buenos Aires and its poorest suburbs, where most of the pickers live. They were left stranded in the city, with some camping out in Buenos Aires' nicest neighborhoods in protest.

That sparked outrage from neighbors such as shop owner Osvaldo Carro, who's helped lead a campaign to block the construction of a recycling center in his middle-class part of town.

He said trash pickers often tear open garbage bags on the street, take what they want and leave detritus strewn across the sidewalk. One picker even threatened him with a broken bottle after he complained, he said.

"They bring with them all their pack of problems," Carro said. "If you give them a hectare of land to work, they wouldn't do it."

To Juan Pablo Piccardo, the city's environment and public spaces minister, the trash pickers are performing a public service even if they upset some residents. He said the city would like to "reintegrate" them into society by teaching them other skills, such as cooking or construction.

"The society has a debt to these people," Piccardo said. "We know a lot of neighbors are disturbed, but these people are working."

To trash-picker advocates such as Jorge Pinheiro of Rio de Janeiro, Brazil, such conflicts could be avoided if governments stopped harassing trash pickers and instead helped them professionalize their operations.

That's already happened in some countries, such as Brazil, where the federal government officially recognized trash picking as a legal profession five years ago and provided some labor protections. Most other countries, however, still prohibit the activity.

Earlier this month, hundreds of trash pickers from 40 countries met in Bogota, Colombia, for the field's first ever worldwide convention. At the top of the agenda was how to win jobs in professional, city-run recycling programs that are beginning to appear around the world.

"This question is changing with more awareness of global warming, which has made more people value the work," Pinheiro said. "We've been seeing more governments working with them rather than fighting them."

That's happened in Duque de Caxias, Brazil, a poor suburb of Rio de Janeiro, where a 100 person-strong recyclers cooperative salvages about 165 tons of material every month from a nearby landfill.

Up until a year ago, the cooperative had separated the garbage at the landfill itself, often under the blazing sun and in dangerous conditions, while surrounded by 3,000 other scavengers also searching for recyclables.

That changed when the city government and state-run energy company Petrobras pitched in to build the cooperative a modern facility near the landfill where its members could work under an awning, with bathrooms and a kitchen on hand. The cooperative's two trucks haul in tons of garbage from the landfill every day for members to sort through.

Each worker earns on average more than $700 a month, which is three times Brazil's minimum wage and about the country's median income. The cooperative keeps close track of how much it's recycling and posts monthly reports on an office bulletin board.

Lately, its biggest moneymakers are white computer paper, PET plastic bottles and cardboard. It sells the material either to intermediaries or directly to factories eager to use the much cheaper recycled product.

"We're not ashamed to say what we do," said Sebastiao Carlos dos Santos, 29, who started trash picking at age 14. "We're not collectors of trash. We're collectors of recyclable materials, and we're saving the environment."

© McClatchy Newspapers 2008