Twenty years ago, a burst of sunny optimism radiated from Rio de Janeiro as world leaders staged a meeting that would prove pivotal.
Amid post-Cold War euphoria and a desire to tackle the problems of the looming millennium, the UN’s 1992 Earth Summit inscribed protection of the planet on the world’s priority list.
It set down a blueprint, Agenda 21, for sustaining nature rather than destroying it, and created UN mechanisms designed to brake the oncoming juggernauts of climate change, desertification and species loss.
Leaders gather once more in Rio from June 20-22 for the 20-year follow-up to that great event.
But how very different the world is today, and how much darker the mood.
By almost every yardstick, as the UN Environment Programme reported in a landmark assessment last week, our planet is sicker than ever.
Despite the rising prosperity in China, India and other emerging giants, billions remain in the rut of poverty.
And as the world’s financial calamity nears its fourth anniversary, the ability — and will — of countries to embrace green growth is badly constrained.
‘Governments are mired in crisis and their eyes are fixed on the present, whereas Rio+20 requires them to calmly draw up a future for the planet,’ Brice Lalonde, a former French environment minister who is co-coordinator of the summit, said.
‘It’s hard to do the two things at the same time. But that, in principle, is what heads of state are there for.’
Around 115 leaders are expected for the summit, which will cap more than a week of meetings gathering as many as 50,000 activists, business executives and policymakers.
This frenzy of contacts and deal-making could well be more fruitful than the UN process itself, say some. The nation-state system remains traumatised by the failures of the 2009 climate summit in Copenhagen.