It should have been September 11th. The Earth Summit was brought forward so its final day today would not be clouded by painful memories - yet the shadow of the Twin Towers hung over Johannesburg nonetheless.
Fear that the world's poor and angry billions can no longer be kept at arm's length lent whatever sense of urgency could be discerned among rich nations' leaders as they signed up to a wordy but toothless UN action plan to end what South Africa's president called the "global apartheid" poisoning the planet.
For evidence that two worlds are now one, the head of the World Bank James Wolfensohn said, "we need only think of the image of the twin towers of the World Trade Center". There was an urgent need for the rich to end poverty and defuse the anger spilling over the crumbling frontiers of their global village.
Though Western governments play down any links between Third World poverty in general and the attacks on the United States, officials in Johannesburg acknowledged that a sense of the danger of ignoring the anger was driving policy as never before.
"A year after September 11, the key issue is do we create a fairer world order, or do we fall into a complete lack of order," said Germany's Development Minister Heidemarie Wieczorek-Zeul.
A "precautionary peace treaty" for the 21st century, was how the head of the UN Environment Programme, Klaus Toepfer, described the summit's goals. Self-interest in securing peace at home is a stronger force for change than feeble altruism.
The symbolism of South Africa was ubiquitous, eight years after the white minority agreed to share its power rather than live under the threat of bloody revolution. "Global apartheid" was just as unsustainable in a shrinking world, delegates said.
The 10-day World Summit on Sustainable Development in the plush Sandton Convention Centre ended with pages of fine words, setting goals for "halving poverty" and cleaning up the environment, healing the sick and saving rare species.
But the broken promises of the Rio Earth Summit 10 years ago remain more real to those just outside, living in the squalid, AIDS-infected slums of one of Africa's most crime-ridden cities.
US Secretary of State Colin Powell, standing in for the conspicuously absent President George W Bush, had a taste of that frustration when activists heckled him during a speech about Washington's commitment to the poor and the planet.
Comparing the World Trade Center to the Biblical symbol of mankind's self-destructive arrogance, Uganda's President Yoweri Museveni, a darling of international financial institutions, said Africans were sick of Western hypocrisy and ready to fight.
"The Western countries are engaged in building the Tower of Babel and that tower will collapse and affect all of us," he said. "We fought colonialism. We can fight this double talk."
He demanded fair access to Western markets and an end to destructive consumerist damage being inflicted on the planet - key pledges renewed at the summit, but in the vaguest of terms.
If unlike Rio de Janeiro this summit is followed by results, it will have to do with real, self-interest concerns in the West and have little to do with the texts signed, most of which had been agreed in other UN forums before, although some said it would influence the agenda of truly powerful global bodies, like the World Bank and International Trade Organisation. Calling such UN declarations "vague and woolly" as a result of compromises between strongly opposed interests, international law professor Robert Hudec of Tufts University said they had little value as law and relied on political will.
Citing a renewed pledge to halve the numbers living on less than a dollar a day by 2015 - a goal hailed by some as firmer than most because of the deadline - he said: "Here you can never have a legal commitment because everybody is responsible. So nobody is responsible. There's no court you can go to."
The same could be said for the other much trumpeted targets - to restore fish stocks, save species, clean up trade in toxic chemicals or provide sanitation - let alone pledges to "aim to reduce" unfair trade barriers, "improve efforts" to promote green fuels or "make every effort" to halt global warming.
"In 10 years you'll have a slightly angrier group of people who'll press some sort of claim," Hudec said, adding this "soft law" could be hardened up over decades of being reaffirmed.
"But it's a political process."
If Western politicians have long failed to keep promises - like a 30-year-old target for aid that was repeated again on Wednesday or Rio pledges to slow global warming - it is because their voters have shown little interest in paying for them.
There may just be signs of change in that political climate after September 11th and growing awareness of changes in the climate, for example with last month's floods in Europe.
Though no fan of what she sees as the Bush administration's promotion of oil interests, veteran American environmentalist Hunter Lovins said she saw signs that some US policymakers were taking seriously security risks posed by environmental damage. She numbers the Pentagon among her consultancy clients.
"[Many] people in the military ... realise that unless the US gets serious about creating real security around the world they are going to have to fight increasingly unpleasant wars in unpleasant places over various resource issues," she said.
At Rio, Western capitalism was basking in its Cold War victory. In Johannesburg, industrialists were out in force to convince cynics that "partnership" projects for the environment and the poor reflected a genuine concern that a divided world burning up its resources was bad for business in the long run.
"This is not about compassion," said Carly Fiorina, chief executive of US computer giant Hewlett-Packard.
"This is about enlightened self-interest."