With less than a week to go for the Rio+20 summit on sustainable development, it looks like only some of the G8 heads of State will turn up for this 20th anniversary of the Earth Summit of 1992. The presidents of France and Russia have announced their intentions to come, but the US president, German chancellor and the British prime minister have said they won't be attending. This is despite the fact that all the G20 leaders will be attending a summit in Mexico, just a short flight away, the day before the Rio summit begins.
Does it mean that the old rich countries are turning their backs on sustainable development? Is it because G8 nations are among the greenest and fairest, so they've got little to learn? Sadly, this is not the case. Both Barack Obama and David Cameron face hostile domestic politics that paint United Nations summits as a waste of time. Neither is willing to speak clearly and with vision about why sustainability has to be at the heart of any plans for growth. Angela Merkel has better green credentials, but is distracted by the biggest political crisis since the European project was launched.
Some sceptics argue that greening the economy is something you can afford only when it's booming, and that we need to hold off imposing environmental burdens on a private sector struggling in a double dip recession. But others insist that we will get no long-term growth and prosperity unless we rebuild our economies along much more sustainable lines. There will be winners and losers in this transformation of the economic system. And we have paid little attention to the politics of transition towards sustainability.
Governments that take this agenda seriously can help their businesses prepare for the world of the 21st century in which resource scarcity bites and a low-carbon economy is the only possible path. Governments that always put sustainability off for another day do their businesses no favours. Instead, governments need to be shaping the ideas, approaches and tools that will push domestic and global activity along greener lines.
In contrast to Rio92, the Rio 2012 agenda is no longer a G8 project. Instead, its outcomes will be shaped by low- and middle-income countries. There is much merit in this. With fewer vested interests and less-embedded infrastructure than in G8 nations, there should be greater room for innovation and getting investment into low-carbon transport, energy and housing.
But the Rio+20 agenda also needs to respond to the interests and priorities of low-income countries, which need investment in the infrastructure, institutions and incentives to allow them to grow incomes and prosperity along low-carbon paths.
If low- and middle-income countries are ready to talk about the challenge posed by living on a small, shared planet, rich nations must also do their part - by consuming less, with fewer environmental impacts, and cutting waste. Problems don't go away by ignoring them. A managed transition to a green economy over the next decade is better than the shocks that will result from inaction. G8 nations have a duty to engage - or risk a backseat in the sustainability race.
Camilla Toulmin is director, International Institute for Environment and Development. The views expressed by the author are personal.