Is the Rio+20 glass half-empty or half full?

It took more than a year of preparatory negotiations and somewhere between 45,000 and 50,000 people converged Rio from all corners of the global to “chew the fat” for up to 10 days (since there are always pre-meeting meetings and parallel “summits”) but what, in the end, did the 2012 United Nations Conference on Sustainable Development actually achieve?

According to Sha Zukang, a Chinese diplomat who had the unenviable job of being Secretary-General of Rio+20, a "substantive" outcome document has been adopted.

"This is an outcome of intergovernmental negotiations, in full consultations with all nine major groups, including business and industries," he said at Friday's closing press conference. “This is an outcome in which no one is happy. Our job is to make everyone equally unhappy. Equally unhappy means equally happy."

No wonder diplomacy is said to be an art! Others, however, were not inclined to be so diplomatic, with UK Deputy Prime Minister Nick Clegg calling the outcome “insipid”. He was obviously still doing his best to be polite.

After months of trying to hammer out a more ambitious document, and faced with the prospect of complete failure to agree, negotiators (by which is primarily meant bureaucrats) ended up opting for the lowest common denominator. Just hours before Rio+20 opened on Wednesday, they agreed on the wording for the final draft of the conference communiqué, dubbed The Future We Want, that appears to move global sustainability little further forward.

Out went any kinds of proposals activists contend are required to avoid an environmental meltdown. So gone, for example, was the perfectly sensible call to end subsidies for fossil fuels or any suggestion of how agreement might be reached on protecting the world's oceans outside of national jurisdictions.

Du Ying, head of the Chinese preparatory committee for the Rio+20 Earth Summit, told reporters on Friday in Rio de Janeiro that one of the successes of the summit was that it didn't backtrack on the principles of the Rio Declaration, such as the principle of "common but differentiated responsibilities". So, apparently, failing to move forward can be regarded as a success.

Instead the emphasis was put on reaffirming what had already been agreed in Rio 20 years ago and at the Johannesburg Earth Summit in 2002, with the word "reaffirm" used 59 times in the 49-page document. There was also broad agreement to hold further meetings to talk about these things. (At least the bureaucrats will be happy with that.)

According to China Daily other important gains of the outcome document include strengthening the environmental pillar with the United Nations Environment Programme, (the bureaucrats will be pleased with that too) as well as measures and goals to improve food security and protect the oceans (or not).

Having bravely agreed in advance not to do anything “substantive”, heads of state and leaders of government from more than 100 countries – plus assorted senior ministers bringing the total nations represented to 190 – arrived in Rio for three days of largely symbolic pontificating.

They also provided a substantial short term stimulus to the economy of Rio de Janeiro. In answer to a question in the European Parliament, the European Commission was forced to reveal that the cost of sending Commission President José Manuel Barroso along with an entourage of more than 60 to Rio+20 conference was about USD740,000 (around USD12,333 per head), entailing the emission of about 300 tonnes of carbon dioxide.

So, with up to 50,000 having come to Rio, the cost and environmental footprint of Rio+20 was what? I guess we'll never know, but it is just as well these Earth Summits only come around every decade.

On the flip side, however, Secretary-General Sha was right to point to the 692 voluntary agreements announced during the main and side events of Rio+20.