Brazilian President Dilma Rousseff welcomed world leaders to a rainy Rio de Janeiro on Wednesday under a cloud of criticism that a three-day summit is falling far short of its promise to establish clear goals for sustainable development.
Before the official start of the event, known as Rio+20 because of the landmark Earth Summit in the city two decades ago, Brazil convinced visiting delegations to finalize a draft declaration for their leaders. But many delegations and summit organizers - as well as outraged environmentalists and activist groups - are lambasting the document as weak.
"Let me be frank: Our efforts have not lived up to the measure of the challenge," said Ban Ki-moon, the United Nations secretary general in opening remarks. "Nature does not wait," he added later. "Nature does not negotiate with human beings."
The draft document, finalized on Tuesday, laid out aspirations, rather than mandatory goals, on issues like food security, water, and energy. It also called for countries to pursue so-called "sustainable development goals," a vague set of U.N. objectives built around the environment, economic growth, and social inclusion.
Many of those who agreed upon the draft, however, say it was stripped of vital specifics. "I was disappointed that we did not go further," said Nick Clegg, Britain's deputy prime minister, in prepared comments on Wednesday.
Expectations have long been low for the gathering, which is expected to include nearly 100 heads of state and government by the time it concludes on Friday. Many leaders at present are more focused on the global economic slowdown and the debt crisis in Europe.
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Despite the presence of the president of France and the Russian and Chinese prime ministers, several other high-profile leaders are missing, including U.S. President Barack Obama and Germany's Angela Merkel.
Compared with the original Earth Summit, which led to historic decisions on biodiversity and greenhouse gas emissions, organizers say this summit is only the beginning of a new goal-setting process for global development. The 1992 event, they point out, was the culmination of years of prior negotiations.
Rio authorities, gearing up to host the World Cup and Olympics later this decade, have been working to put a friendly face on the gathering. The city's famous Christ the Redeemer statue is illuminated green, its glow shining nightly on epic traffic jams and motorcades below.
Demonstrators, meantime, have made their displeasure known.
Outside the summit, a gargantuan series of warehouse-like conference halls in the strip mall-filled suburbs of southern Rio, environmental activists, political parties, and others marched through steady drizzle and called for bold action.
Earlier this week, bare-breasted feminists marched through the city center and Amazonian tribesmen, donning war paint and arrows, descended upon Brazil's national development bank, which is financing dams and other controversial infrastructure projects in the Amazon rainforest.
Diplomats said Brazil's push for a draft document had opposing outcomes. While it forced delegations to focus and come to an agreement, it may have prematurely shut the door on bolder action by leaders when they arrive.
That, they added, leaves little leeway for the draft to improve before a final pronouncement on Friday. "Everybody has things that they have given up in the document in one way or the other," said Todd Stern, U.S. special envoy on climate change. "This is the thread that once you start pulling on it, it unravels quickly."