Environmental problems result, it is said, from the rich dumping on the poor and the present dumping on the future.

That is one way to illustrate the issues to be addressed at the United Nations sustainable development summit in Rio de Janeiro this month.

It is something of a caricature. But it reminds us that sustainability requires not just a technical fix but also a political commitment to fight poverty and a moral recognition of the interests of future generations.

The global community has grappled with these issues for 40 years since the first United Nations conference on the “human environment” held in 1972 in Stockholm, that opened on June 5.

Now World Environment Day, this day recalls the launch of the “global green flag” on its long march to Rio in 1992, Johannesburg in 2002, and now “Rio+20”.

Much has been achieved along the way – through regulation, economic incentives and education – to encourage and entrench cleaner production technologies and more intelligent modes of consumption.

With growing prosperity and widening awareness, the common sense of saving energy and other resources has made great strides in many societies, as has the demand for efficient infrastructure and public services.

The road from Stockholm has not been easy, however. While the “green flag” flies high in political rhetoric, it is often marginalised in decision-making. Economic defensiveness and “short-termism” pose formidable obstacles to mainstreaming sustainability.

When the electoral chips are down, the political knee-jerk reaction is to focus on core economic issues: jobs, access to basic needs.

Long-term vision drifts off to the periphery when the rallying call is “It’s the economy, stupid!”

These tensions between present and future, between rhetoric and reality are nowhere more evident than in the intergovernmental negotiations on limiting human-induced climate change to a manageable level – the headline issue since the last Rio summit.

The adverse consequences of dumping greenhouse gases in the atmosphere are beyond the time frame of most political calculations.

The approaching catastrophe is surreptitious, not a big bang but a stealthy creep. And even that is blurred by a counter-campaign of pseudoscientific scepticism.

Moreover, the dynamics of negotiations on contributions towards a common good do not give rise to exchanges of tangible quid-pro-quos, such as those that can drive convergence on disarmament or trade.

Effective and lasting agreement on safeguarding the earth’s climate system must be founded on shared intangibles: ethics, equity, responsibility and political will. Rio is a rendezvous for leaders of governments along the road from Stockholm.

What signs of hope can they offer from this staging point?

First, that governments are focused on promoting the real economy that responds broadly to people’s diverse needs, rather than on protecting abstract markets.

Second, that governments are integrating sustainability in their economic strategies and decisions.

It would be positively symbolic if heads of government decided to be accompanied to Rio by their ministers for economy and finance, not just their environment ministers.

Third, that governments recognise not only the upfront costs of investments in a cleaner economy but also the collateral benefits – for example, the benefits that cleaner fuels bring to air quality and, thus, to respiratory health.

Fourth, that governments understand the need to probide frameworks and incentives for profitable investment in sustainability.

In a market economy, a vision of profits to be gained from innovation for the long-term must be one of the main drivers towards sustainability.

Examples of responsible initiative by smart business exist and should be highlighted.

Corporations can often take a longer view than governments – but governments must point the way.

Finally, that governments are committed to fight poverty at home and abroad.

When the environment was put on the global agenda at Stockholm, only one foreign leader participated: the Prime Minister of India, Indira Gandhi.

She proclaimed then that poverty is the worst form of pollution. That profound sound-bite still echoes.

It should be played back in Rio at the opening of “Stockholm+40”.

The author set up and headed the secretariat supporting the United Nations Framework Convention on Climate Change from 1991 to 2002 and, until last year, served as Malta’s Ambassador on Climate Change.