Word on the street in Rio is that the United Nations Summit on Sustainable Development, a two-day meeting of hundreds of leaders from around the world, is turning out to be a major bust.

The gathering is known as Rio+20, a reference to the two decades that have passed since a 1992 environmental conference, called the Earth Summit, took place in the same Brazilian city of Rio de Janeiro. This time around, the issue at hand is a would-be-seminal document called The Future We Want, which Rio+20 delegates have drafted and are supposed to adopt.

The paper, which is about 23,000 words in length, is meant to outline a global plan for sustainable development -- that is, a way to ensure that economic growth progresses in a way that is environmentally and socially responsible.

A draft of the document was released on Tuesday. The verdict?

It's pathetic, said Jim Leape, head of the World Wide Fund for Nature, to the Guardian. Many politicians and organizational heads agreed with that assessment, deriding the draft in no uncertain terms. Unfortunately for them, it's likely to pass without many changes.

If this text proposed by Brazil is accepted, then the last year of negotiations has been a colossal waste of time, said Leape.

Brazil isn't the only party responsible. This version of The Future We Want was largely engineered by the Group of 77 -- a U.N. bloc of 77 developing nations -- as well as China.

In particular, India, China and Brazil have become the most powerful forces behind the Rio+20 proposal. All three are still classified as developing countries, even though their economies are huge and rapidly expanding. Each has achieved newly industrialized country status, putting them in the top economic tier of developing countries worldwide.

The G-77 plan has been blasted by the leaders of developed countries, and by the heads of environmental organizations around the world. It's watered down, say the critics -- unambitious, ambiguous, and barely improved from the precursor agreement that was signed two decades ago.

U.N. Secretary-General Ban Ki-moon acknowledged the complaints in a press conference on Wednesday. Some member states hoped for a bolder ambitious document, he said. I also hoped that we could have a more ambitious outcome document. But you should understand that negotiations have been very difficult and very slow because of all these conflicting interests.

Those interests center on a concept called common but differentiated responsibilities. In a nutshell, this means that those countries with lesser means -- developing countries -- should not be held to the same standards as their richer counterparts.

As the 1992 agreement explained it, The developed countries acknowledge the responsibility that they bear in the international pursuit to sustainable development in view of the pressures their societies place on the global environment and of the technologies and financial resources they command.

During meetings in the days leading up to Rio+20, developing countries led by Brazil, India and China reaffirmed this principle.

Critics, including representatives of the United States and the European Union, argue that this allows developing countries to skirt their responsibilities. Developed countries are loath to shoulder the burden of enforcing sustainability, especially since a global recession has hindered their own ability to devote resources to the cause. They contend that the rapid industrialization of countries like China, Brazil and India in recent years should mean they assume more responsibility in ensuring a sustainable future for the planet and all of its people.

But those developing countries see economic growth as a precondition to establishing sustainable practices.

The inconvenient truth is that sustainable growth in the long term often means slower growth in the short term. If China, for instance, were more focused on addressing its yawning wealth gap, its overall economic progress would get bogged down. If India were committed to improving its deplorable air quality, it would have to find a way to scale back its reliance on coal and devote resources to a costly infrastructure overhaul.

That's not to say China, India and Brazil are to blame for Rio+22's shortcomings; their heavy involvement in the drafting of the new document speaks in their favor.

Brazil hosted the event, giving it a bigger say in proceedings. President Dilma Roussef defended her position on the drafting process last week.

A pro-growth position, to preserve and maintain, is intrinsic to the design of development, particularly in the face of crisis, she said.

And while some developed nation leaders did not bother to show up -- including U.S. President Barack Obama -- Chinese Premier Wen Jibao and Indian Prime Minister Manmohan Singh both flew straight from the G20 conference in Mexico to assert their presence.

Wen has voiced his support for upholding the principle of common but differentiated responsibilities, and Singh has done the same.

We must acknowledge the continuing differences in levels of development across the world and the need for provision of financial and technological support to the developing world if we are to work together as a global community to address our most pressing environmental challenges, explained Singh before the summit.

And so the chips have fallen, and now the chips are down. This is a definite victory for G-77+China, but opponents say it's terrible news for everyone around the world who suffers unjust levels of poverty, chronic hunger, or an increasingly inhospitable environment.

Some, like summit attendee and Oxfam spokesman Stephen Hale, held out hope that the final meetings might yet yield necessary changes. But at this point, the hour is late and most see little likelihood of change.

Everybody should look in the mirror and ask what history is going to make of this. We face connected crises. Rio+20 should be a turning point, but it is a dead end, said Hale to the Guardian. This summit could be over before it's started. World leaders arriving tonight must start afresh. Almost a billion hungry people deserve better.