Greenpeace reiterated its call for an end to deforestation in Brazil by 2015 and globally by 2020 during its launch of an awareness-raising expedition down the Amazon River aboard the Rainbow Warrior. \"Brazil is now the sixth largest economy in the world, the largest meat exporter and second largest grain exporter. Brazil’s rise to become the world’s sixth largest economy coincided with consecutive years of decline in deforestation in the Amazon,” said Kumi Naidoo Greenpeace International Executive Director. \"Brazil must lead as an example of sustainable development without forest destruction for other forest countries like Indonesia and the Congo.” The Greenpeace voyage is timed to end in Rio around the start of the Rio+20 conference on sustainable development. The conference is expected to attract thousands of business and political leaders, as well as scientists, activists, and academics. While the annual deforestation rate in the Brazilian Amazon has fallen by nearly 80 percent since 2004, environmentalists fear the country\'s politicians may backslide on their commitment toward greener economic growth. “Brazil could be the example of an economic super power that continues to grow without recklessly destroying the forests. However, actions over the past year by President Dilma and the Brazilian congress show that we are at risk of failing to achieve this,” said Paulo Adario, Greenpeace Brazil’s Amazon Campaign Director. “It will only be with a strong legal framework that Brazil will have the necessary tools to continue to fight deforestation.” Greenpeace has therefore launched a petition calling for a \"zero deforestation\" law in Brazil. It is seeking 1.4 million signatures of Brazilian voters for the initiative. \"The proposed law is an initiative started after the blatant dismissal of widespread public opposition to the new Forest Code law by the Government in favor of vested agribusiness influence,\" said Greenpeace in a statement. \"Brazil\'s Amazon Rainforest is currently facing intense pressure from cattle ranchers, the agriculture sector, loggers and large infrastructure projects all threatening to undo legislation that has helped to protect the forests of Brazil for years.\" Brazilian lawmakers and President Dilma Rousseff are currently weighing a revision to the country\'s forest code, which governs how much forest a landowner is permitted to clear. Environmentalists fear the legislation could grant amnesty for landowners who illegally cleared millions of hectares of rainforest. Supporters of the revision say it could make the Forest Code clearer and easier to enforce while allowing Brazil to expand export-driven agriculture deeper into the Amazon. A vote on the measure is expected in coming weeks. Greenpeace is urging President Rousseff to reject the revision. Deforestation remains a critical environmental issue globally. More than half of Earth\'s terrestrial plant and animal species reside in tropical forests, while deforestation and forest degradation account for 10-15 percent of greenhouse gas emissions. Forests also provide important ecosystem services, including maintenance of rainfall and moderation of local climate, that form the basis of rural and urban economies. For example, roughly 70 percent of GDP in South America is produced within the rain shadow of the Amazon rainforest. Greenpeace is not alone in its target. WWF, one of the world\'s largest environmental groups, has a zero \"net\" deforestation target for 2020.