UN talks on sustainable development are encountering disputes, delays and diplomatic wrangling, days before world leaders arrive to sign a new agreement.
Talks in Rio de Janeiro are aimed at putting the world economy on a more sustainable path, helping people out of poverty while protecting nature, the BBC reports.
Yet developing countries have walked out over money, and environmental campaigners say there is little hope of momentous changes being agreed here.
"That's not even a question anymore," said Lasse Gustavsson, executive director of conservation with WWF International.
"It's clear we will get something, but it's equally clear we will not get what the planet needs," he told the BBC.
Preparatory talks broke down on Thursday as the G77/China bloc of 131 developing countries walked out of a number of sessions.
Dispute over cash aid
They decline to talk about issues such as the green economy - which some see as likely to put a brake on development - unless western nations are clear about the amount of financial aid they were prepared to pledge.
The draft agreement negotiators are working on contains paragraphs that would commit the developed world to providing either $US30 billion a year or $US100 billion a year - but western governments are not prepared to agree to either figure.
Discussion groups reconvened on Friday morning; and Nikhil Seth, head of the Rio+20 secretariat, told reporters there was a "sense of cautious optimism and constructive engagement".
But he said only 28% of the negotiating text had been agreed - an increase of 8% in two days.
Responsibility for the talks passed to the Brazilian government on Friday evening.
Luiz Alberto Figueiredo, director of environment in Brazil's foreign ministry, said the pace would pick up in order to finish the talks by Tuesday, when heads of government arrive.
"Only essential issues will be discussed so we can reach a text as soon as possible," he said. "Now it's the final hour."
More than 26,000 delegates have now been registered for the summit, including politicians, government negotiators, journalists and business leaders.
NGO groups dominate
But the biggest contingent comes from groups campaigning either for poverty alleviation or environmental protection; and they appear uniformly frustrated by how much time is being taken up on detailed haggling rather than on agreeing a visionary outcome.
"It is developing countries and the world's poorest people who have the most to lose from a weak outcome at Rio+20," said Stephen Hale of Oxfam.
"We urgently need Brazil to step forward and persuade other countries to make commitments that match the urgency of the challenge."
WWF suggested that European heads of government, who are in the main staying away, should re-assess their priorities.
The UK's David Cameron and Germany's Angela Merkel are among those who are scheduled to attend the G20 meeting in Mexico on Monday and Tuesday before flying back to handle any fallout from Sunday's general election in Greece, rather than making the comparatively short hop to Rio.
"We have most of the heads of government, even heads of state, coming in from emerging economies - their GDP is about 30% of the world total, Greece's is about 0.37%," said Mr Gustavsson.
"We may look back on this as a historic moment when Europe handed over the sustainable development baton to the emerging economies."