Yet more failure to make much progress on climate change in Durban means that developing countries must exert stronger political pressure.
For three years in a row, there has been a disappointing end to international meetings that should have agreed on the steps needed to prevent the human and ecological disasters likely to result from a failure to limit man-made climate change.
The stage was set in Copenhagen two years ago, when the 15th Conference of the Parties to the UN Framework Convention on Climate Change (COP 15) — widely but perhaps misleadingly billed by environmentalist groups as "the last chance to save the planet" — ended in disarray.
Following an equally disappointing meeting in Cancun, Mexico (COP 16), last year, expectations were low for the outcome of this year's meeting, which took place in Durban, South Africa (COP 17), earlier this month. The financial crisis that has hit industrialised countries over the past two years further lowered expectations, pushing climate change far down their political agendas.
There was, therefore, little surprise that the Durban meeting failed to make much headway, beyond agreement to start negotiations on a new agreement for 2015, to come into effect in 2020.
But the message of Durban was clear for climate change and other sustainability targets. A global transition to a green economy is unlikely to take place through voluntary agreement. It will require strong political leadership, and this must now come from developing countries — emerging economies in particular — which have much to gain from achieving sustainable growth.
The technical aspects of this transition are relatively easy to define (and technologies such as bamboo charcoal were on display in Durban). The way forward is through development and deployment of clean energy systems.
Solar energy is the obvious contender here. And the developing world, where most countries enjoy significantly more sunshine than those in temperate regions, are best placed to benefit from these technologies, provided that innovation and mass production brings down the costs of equipment such as photovoltaic panels. In the case of large-scale projects, such as Desertec, countries may even profit financially by exporting solar energy.
Other technologies also need to be introduced. In agricultural production, for example, carbon emissions could be reduced by techniques such as low-tillage cultivation, and for house building there are many opportunities to cut the energy used in constructing and maintaining homes.
And creating a green economy does not depend only on meeting the technical challenges of mitigating climate change. Equally important is the need to introduce food production techniques (such as biological pest control) that can boost agricultural output while ensuring there is sustainable and equitable use of natural resources and ecosystems.
Political and economic obstacles
So the technical advances needed to build a green economy — as well as the scientific research required to bring new technologies to fruition — are relatively easy to identify and develop. Indeed significant progress has been achieved since the Earth Summit in Rio de Janeiro almost 20 years ago, as is likely to become clear at next year's Rio+20 summit, to be held in the same city.
The stumbling block, as the Durban meeting illustrated dramatically, lies in the political and economic interests that stand in the way. Those who represent these interests appear to argue that 'business as usual' — taking signals from the market alone — will be sufficient to lead the world on a path towards long-term sustainability from enlightened self-interest. But the spectacular failure of this strategy in the case of the global financial industry carries a sobering message.
Take, for example, the question of intellectual property rights. Many of the new energy technologies have been produced in the laboratories of the developed world, which inevitably seek to exploit them for financial advantage. But the need for them remains greatest in the poorest parts of the world, which are often unable to pay high licensing fees.
Attempts to lower these fees have, so far, had only minimal success, and no progress on this front was achieved in Durban.
Case for social equity
All this suggests that stronger political action from the developing world (with backing from sympathetic countries in the developed world) will be needed to create the conditions that allow a green economy to flourish.
A strong case can be made on the grounds of social equity. As Sunita Narain, director of the Centre for Science and Environment in New Delhi, India, has persuasively argued, equity suggests that those countries largely responsible for creating the climate change problem should take the biggest share of responsibility for finding a solution (and providing the resources for doing so). 
Enlightened self-interest will be needed, too. Countries such as Brazil and India are already experiencing the social and environmental fallout of unfettered economic growth. The more severe the consequences, the more they will realise that their future wellbeing depends on pursuing a different growth paradigm to that in the developed world.
The political will — and capability — to translate sustainability goals into effective actions must be the priority for all countries. For emerging economies, in particular, which are becoming increasingly powerful actors on the global stage, it needs to stay not only near the top of their political agendas as they prepare for next June's meeting in Rio, but also for many years to come.