The Earth Summit is mercifully over, leaving us all to wonder: What the hell happened last week? Did the end result justify the 3,600 tons of CO2 generated by the U.N. delegation alone? And has anyone seen my pants?

Rio+20 was like Carnival without the party — unless you consider 50,000 people cramming into conference centers, soccer stadiums, and makeshift meeting halls, all struggling to access the internet and navigate between venues as much as three hours apart by bus a good time.

The official summit and negotiations were, as we predicted, a bomb. The final “outcome document” [PDF], signed by world leaders last Friday, brings empty political speak to new heights. The 49-page tome amounts to a long list of “acknowledgements,” “affirmations,” and “underscorings” of statements and agreements already put in writing years or decades ago.

In a nutshell, the leaders of the world said, “We recognize that we are in deep doo-doo, and we need to do something about it.” What that “something” is remains unclear.

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Even where clear solutions exist, they were laughably noncommittal. Consider this paragraph, about ending fossil fuel subsidies:

Countries reaffirm the commitments they have made to phase out harmful and inefficient fossil fuel subsidies that encourage wasteful consumption and undermine sustainable development. We invite others to consider rationalizing inefficient fossil fuel subsidies by removing market distortions, including restructuring taxation and phasing out harmful subsidies, where they exist, to reflect their environmental impacts, with such policies taking fully into account the specific needs and conditions of developing countries, with the aim of minimizing the possible adverse impacts on their development and in a manner that protects the poor and the affected communities.

That’s right. We “invite” you to “consider rationalizing” those subsidies — but only if you really want to. That’s leadership!

Granted, fossil fuel subsidies are a tricky issue, and they were not a big priority for this summit. But check out this gem, from the paragraph hailing the launch of U.N. Secretary General Ban Ki-moon’s ambitious Sustainable Energy for All initiative, aimed at bringing solar and other renewable energy sources to the world’s poor:

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We are all determined to act to make sustainable energy for all a reality, and through this, help eradicate poverty and lead to sustainable development and global prosperity. We recognize that countries’ activities in broader energy-related issues are of great importance and are prioritized according to their specific challenges, capacities and circumstances, including energy mix.

Again, we are totally committed to making this happen, except when we’re not. Now can we all go home?

The summit has been panned as “perhaps the greatest failure of collective leadership since the first world war,” “a staggering failure of responsibility,” and other less family-friendly things. Leaders in the developed world failed to deliver a requested $30 billion to help developing countries make the transition to a green economy. A proposal to protect the “high seas” — those areas outside the boundaries of national waters — dried up and blew away. And throughout the text, language was watered down to appease world leaders who, almost without exception, plead poverty.

The bright spots from the official talks, if you can call them that, include:

  • Hey poor people, here’s a turbine or two: Despite the flaccid endorsement in the outcome document, the Sustainable Energy for All initiative won wide backing from individual nations, banks, and private investors, who pledged over $80 billion to make it a reality.
  • Oceans, you’re all right: While the high seas rescue plan failed, there was wide agreement on the need to do more to protect oceans and fisheries. Again, world leaders were long on talk and short on action, but this seems like one area where the international community is poised to actually make real progress in coming years.
  • Go for the goals: The gathered nations also pledged to develop a set of “sustainable development goals” by 2013 that will replace the Millennium Development Goals, a set of priorities that have been adopted by all of the U.N.’s member countries. It’s a baby step at best (unable to agree on specific goals, the Rio delegates created a “high level political forum” that will spend the next year and a half developing some recommendations), but it is a sign, at least, that sustainability will become a central tenet to international development policy.

Is that meager progress worth 3,600 tons of CO2? You decide. But the U.N. wasn’t the only outfit throwing a party in Rio last week. There were dozens of sideshows, subconferences, media events, and award ceremonies around the city, and these were the sources of the most notable progress. A few examples:

  • Banking on transit: In what was arguably the biggest announcement of the week, international development banks promised to spend $175 billion to promote transit, bike lanes, and other sustainable transportation in the world’s largest cities.
  • Fishy business: While the U.N. could only commit to toothless pledges of future action, Australia, the Maldives, and Mexico actually drew some lines in the sand, unveiling substantial new ocean and fisheries protections.

The Natural Resources Defense Council (NRDC) has created a website called Cloud of Commitments to promote — and track — the multitude of pledges made at the summit. But the real question is how the NRDC, or anyone else, will make those in the cloud live up to their promises. At minimum, they’re gonna need a lot of interns.

But beyond all the wrangling, speechifying and promise-making, Rio offered a clear look at the human spectacle, and the challenges that lie ahead as we hurtle toward 9 billion people on this planet.

Rio is a metropolis of more than 12 million souls. Its traffic is epic, its air thick with diesel exhaust and cigarette smoke, and its turquoise water so polluted that it is unsafe to swim in much of the year. The chasm between rich and poor yawns wide, though they live side by side, with slums spreading up steep hillsides above posh, beachside neighborhoods, and catadores wheeling carts of scavenged recyclables through the streets alongside shiny luxury cars.

One evening, as the early winter darkness fell over the city, I walked through the seaside park that was home to the People’s Summit. Two young boys splashed in the surf as scissor-tailed seabirds glided silently overhead. Out in the water, lights twinkled on a massive oil platform as container ships moved in and out of port, delivering goods from the far corners of the ever-shrinking globe. On the city skyline, a sign lit up in neon green: Hotel Novo Mundo.

Welcome to the new world, my friends. We’ve got a lot of work to do.