In the next few days, world leaders will be gathering in Rio de Janeiro, the Brazilian capital, to renew a decades-long commitment to global sustainability.

However, negotiators are still locked in pre-summit haggling over sticky issues before a consensus could be reached at a meeting seen by UN chief Ban Ki-moon as a "generational opportunity".

LITTLE PROGRESS

Twenty-five years ago, the Brundtland Commission of the United Nations coined the term "sustainable development" in its report, calling for a growth model that "meets the needs of the present without compromising the ability of future generations to meet their own needs." Five years later, a landmark Earth Summit in Rio de Janeiro adopted a comprehensive plan of action, known as Agenda 21, entailing global and national actions to advance sustainability.

Now, 20 years on, there has been little progress to that effect. In a 525-page report released on June 6, the UN Environment Program (UNEP) warned that the bio-ecological system of the Earth is being pushed towards or already over its "biophysical limits", and if the status quo continues, catastrophic and irreversible changes could follow.

One of the reasons behind the slow action is that the world tends to ignore the "fundamental causes" while looking for solutions that are more "on the outside edges," said Janos Pasztor, executive secretary of the UN High-level Panel on Global Sustainability (GSP), in an exclusive interview with Xinhua.

For example, the world often looks at the environmental impact of what is happening, and then comes up with adaptation measures on how to live under those environmental impacts, instead of looking at what the cause is and then try to solve it, he said.

Weak political will is another important reason, Pasztor noted. "Leaders, whether they are in government or private sector, are still looking at the short-term horizon."

"They want to be re-elected. They want to make quick money and the economy (model) allows them to make quick money and allows them to continue to rip the Earth and use the atmosphere as a free good because there is no price and no penalty."

Now, the world has a rare opportunity to revitalize the cause of global sustainability at the June 20-22 Rio conference, a follow-up to the Earth Summit after a two-decade interval. Over 100 world leaders are expected to attend the historic event, with participating delegates totaling up to 50,000.

Their mission is to renew commitments in the fields of economy, society and environment, the so-called three pillars of sustainable development, and to tackle new sticky issues -- a green economy and a mechanism to look after sustainability affairs, which are two themes at the forthcoming summit.

A successful outcome is by no means easy to achieve, as evidenced by the 6,000-page negotiating text when the talks began, and the "painfully slow" pace of negotiations as described by the UN secretary-general.

GREEN ECONOMY

First, leaders will have to agree on an inclusive green economy, the concept of which was largely initiated by developed countries, where people generally enjoy an affluent life style and worry more about environmental degradation.

But developing countries comprising the majority of UN member states are skeptical about whether a green economy would be leaning to the green side too much at the expense of poverty- reduction, a priority for them.

Some developing countries are suspicious that this is another way to restrict their sustainable development, to "commodify in the name of green economy" and "to commodify their technologies and goods to the developing world," Ban told a small group of journalists in a recent briefing.

In fact, it was under the request of developing countries that the summit's theme was officially changed to "a green economy in the context of sustainable development poverty eradication", to reflect their concerns.

The difficulty is that developing countries are burdened by the costs in their transition to a green economy, a UN expert directly involved in the negotiations told Xinhua on condition of anonymity due to the sensitivity of the issue.

They are also worried about restrictions caused by assistance conditions or green protectionism. They even harbor suspicion that green economy could become a tool employed to restrict the development of developing countries. These concerns could be lessened if the two sides agree on funding and technical assistance as well as market access to the green products from developing countries.

POST-2015 ERA

Leaders will also have to agree to define the so-called sustainable development goals (SDGs), which more and more countries believe should be a central part of the post-2015 global development framework.

The SDGs will build on the Millennium Development Goals (MDGs), a set of eight anti-poverty and social targets agreed by UN members to achieve by 2015.

The difference is that the SDGs are more wide-ranging than the MDGs as the former covers not only the targets in poor countries, but those in all countries.

Under negotiations are issues related to the SDGs, including how to create specific SDGs, what to learn from the MDG project and how to deal with the relationship between the SDGs and MDGs after 2015.

Pasztor expected no quick decision on a list of specific goals at Rio, as they require a two-track approach -- technical and analytical work to understand and define the goals and political steps to elevate them to an inter-governmental process accepted by countries.

However, Pasztor hoped for "a strong decision" on the need for the SDGs and a feasible process to go forward after Rio to actually develop them.

MECHANISMS OF SUSTAINABILITY

There are also ongoing debates over the institutional arrangements to look after sustainability affairs, the second theme of the Rio summit.

The European Union is calling for promoting the UNEP to a specialized agency like the World Health Organization (WHO), while some other countries argue that just to establish another specialized agency on top of many institutions will not be the answer.

The argument against a specialized agency is that sustainable development is not an environmental issue only, but an issue covering economic, social and environmental pillars.

One option is to strengthen the UNEP with more funding, more membership and more independence.

Another idea is to establish the Sustainable Development Council (SDC) on the basis of the current UN Commission on Sustainable Development (CSD), in a way like the elevation of the UN Human Rights Commission to the Human Rights Council directly under the jurisdiction of the General Assembly.

There are concerns, however, that a new SDC will effectively undermine the UN's Economic and Social Council (ECOSOC).

Pasztor did not expect a quick decision on the SDC, whose key functions include reviewing regularly progress on global sustainability.

"Maybe we need to learn by doing before we create a new council, " he said. "We could do that by simply using the General Assembly as a proxy and begin to try to undertake these functions."

"Then one day, maybe in a year or two, we could be ready to create the council," he added.

Analysts say that the Rio negotiations have largely reflected the divisions between the developed and developing countries, which are rooted in their different development levels as well as different understandings of sustainable development.

In general, underdeveloped countries emphasize development and poverty reduction while developed countries are concerned more about environmental impacts.

However, in the face of continuing ecological degradation and potential disastrous consequences, they share the common goal of seeking a balance among economy, society and environment for the benefit of future generations, which in fact forms the basis of a possible consensus at the Rio summit.