Brazil's success in slowing rain forest destruction has resulted in enormous reductions in carbon emissions and shows that it's possible to zealously promote sustainability while still growing the economy, suggests a new study out Thursday.

A second study out this week also underscores Brazil's success and shows that deforestation has also slowed in several other tropical countries.

Since 2004, farmers and ranchers in Brazil have saved over 33,000 square miles (86,000 square kilometers) of rain forest from clear-cutting, the rough equivalent of 14.3 million soccer fields, a team of scientists and economists from the U.S. and South America report in Science. At the same time, production of beef and soy from Brazil's Amazon region rose.

The country has reduced deforestation by 70 percent and kept 3.2 billion tons of carbon dioxide out of the atmosphere, because forests use carbon as they grow and release it when they are removed, often through burning. That makes Brazil's the biggest reduction in greenhouse gas emissions of any country in the world; the cut is more than three times bigger than the effect of taking all the cars in the U.S. off the road for a year.

"Brazil is known as a leading favorite to win the World Cup, but they also lead the world in mitigating climate change," the Science study's lead author, Daniel Nepstad of the Earth Innovation Institute in San Francisco, said in a statement.

Brazil's success in saving about 80 percent of the original Amazon serves as a model for other countries around the world and represents a "completely different trajectory for forest areas over the last few centuries," says Toby McGrath, a senior scientist at the institute and another of the study's co-authors. (See "Photos: The Last of the Amazon.")

"For the first time in history, we are stopping the process of forest loss on a frontier before it gets seriously depleted, while continuing to develop economies that still have substantial forest cover," says McGrath.

Globally, deforestation is responsible for about 10 percent of all climate emissions, says a study released Wednesday by the Union of Concerned Scientists. That's down from 17 percent of emissions in the 1990s, thanks to falling rates of deforestation.

"Brazil is most notably lauded for their deforestation reductions, but the report found numerous example of successfully saving forests in unexpected locations," study author Doug Boucher, director of the Union of Concerned Scientists' Tropical Forest and Climate Initiative, said in a statement. Mexico, El Salvador, and six countries in Central Africa, in particular, have shown decreased rates of deforestation.

Measure of Success

For the Science study, scientists and economists analyzed how Brazil was able to reverse decades of high rates of deforestation in the Amazon, starting in 2005, when then-president Luiz Inácio Lula da Silva announced the ambitious goal of slashing the rate by 80 percent over the previous year. After that, things turned around due to a number of factors coming together, says McGrath.

One important element was the advancement of remote sensing technology. Although Brazil first passed a forest code requiring landowners in the Amazon to protect at least 50 percent of native forest in 1965, enforcement was spotty. "Officials didn't have good information on where deforestation was occurring and who was on the ground," says McGrath.

Over the past few years, satellites have given officials a more precise picture of the forest, often in real time.

Another boost to deforestation efforts: The forest code was updated in 2012 and now requires landowners to preserve 80 percent of the Amazon's virgin forest, as well as protect watersheds. Those that have violated the rules have increasingly received fines and even jail time in extreme cases.

Nonprofit groups, meanwhile, have helped publicize data on rule breakers and have built support for enforcing the law. Campaigns by Greenpeace, Conservation International, and others put pressure on companies that buy products from the Amazon, especially beef and soy, shaming those that have been found to contribute to deforestation. Market agreements signed by companies took that a step further, prohibiting practices that lead to deforestation.

"In Brazil, there was rising awareness of the value of nature and how essential it is to our society," says Fabio Rubio Scarano, the vice president of Conservation International's Americas Division, who is based in Rio de Janeiro.

In a tough regulatory approach called "critical counties," the Brazilian government also prohibits government loans to all agricultural producers in a county if there's a lot of deforestation going on there. There has been rising opposition to this program, but it has been effective, says McGrath. "It increases internal pressure to make everybody fall in line."

The Brazilian government has also created new protected reserves of forest in the Amazon, especially along frontier areas where deforestation had started. Managing these new areas has effectively stopped its tree loss, says McGrath.

View Images Cattle are big business in the Amazon, though landowners are required by law to preserve 80 percent of the forest. PHOTOGRAPH BY ALEX WEBB, NATIONAL GEOGRAPHIC CREATIVE

Keeping Production Up

Although landowners in the Amazon face restrictions on how much land they can clear, overall production of beef and soy has risen over the past decade, the scientists and economists note.

McGrath says producers have been focused on increasing their efficiency and productivity, in part because they often don't have the option of clearing more land. As a result, many have successfully adopted better management practices.

That process can go further, says Scarano. If land that is currently not very productive could be managed better, then Brazil "could double food production without cutting a single tree," he says.

But farmers could use more support from the government, with a policy that encourages efficiency, he says.

Emerging Threats and Next Steps

Scarano and McGrath both note that 2013 saw a slight uptick in the rate of deforestation in Brazil's section of the Amazon, although the rate remains much lower than it was decades ago.

The cause of the recent changes is unclear, but it could be related to weather patterns, which can encourage more land clearing, as well as rising global demand for food. It also highlights the need for further improvements, both men agree.

A new government program that requires landowners to register their usage plans should help, says Scarano.

McGrath adds that another step should be to strengthen the system for incentives for landowners who follow good management practices. They could receive payments from emerging carbon markets for the amount of greenhouse gases they prevent, or for other "ecosystem services" like protecting water quality.

A few pilot projects have been under way, some funded by a one-billion-dollar grant from Norway and others, tying in to California's growing carbon market.

In a suggestion that some environmentalists might find counterintuitive, McGrath also says international food companies that are committed to preventing deforestation should consider working in additional areas in the Amazon.

"If they don't move into those areas because they are afraid of getting accused of deforestation, then other groups that don't care will move in and will exploit the resources," says McGrath. "Because it is going to get developed somehow."

Brazil’s agricultural lobby had battled with environmentalists over the most recent updates to the Forest Code. But now that the law is in place, the next step has been trying to figure out implementation, says Gustavo Diniz Junqueira, the president of the influential Brazilian Rural Society, which represents agricultural producers in the country.

Junqueira says large producers in the Amazon have effectively ceased deforestation, although some smaller producers are still removing trees. To help reduce that, small-scale producers need more access to technology. They also need insurance coverage, he says.

The Brazilian agribusiness industry is trying to shake its reputation as being “an enemy of the environment,” says Junqueira. “Instead of expansion in new areas, we are looking at how to produce more in the same areas,” he notes. In that way, over the past few years, soy production has been rising six percent a year.

Scarano adds that despite Brazil's success on deforestation, many other environmental problems remain. The country faces big challenges in "reconciling nature conservation with the needs of human well-being," he says.

Planned development of large-scale hydroelectric plants in the Amazon and elsewhere in the country could erase some of the gains that have been made in protecting forests, he warns. The country also hopes to build additional infrastructure as the economy grows.

Some environmentalists, such as celebrity Bianca Jagger, have criticized Brazil for not doing enough to protect indigenous rights and for poor living conditions in vast urban favelas, including water quality issues. As the world looks to Brazil for the World Cup and Olympics, those issues may come into sharper focus.

"Planning must take into account many factors, including nature," says Scarano. And when it comes to stopping deforestation, "there's no one right way," said Boucher of the Union of Concerned Scientists. "But rather a smorgasbord of options."