World's environment ministers said a transition to a low-carbon "green economy" is crucial for sustainable development, saying that the next meeting in Brazil offers a key opportunity for acceleration.

The ministers who are meeting in Nairobi said potential challenges, including new kinds of trade barriers, need to be managed.

But a green economy offers a way of realizing sustainable development in the 21st century by "building economies, enhancing social equity and human well-being, while reducing environmental risks and ecological scarcities."

"The efforts to strengthen international environment governance should be about more than rationalization of fragmentation and seeking efficiencies. Instead it should be about re-envisioning and even dreaming about what it required institutionally for environment and sustainability, and putting this in place," said the summary, whose chair was Rosa Aguilar Rivero, minister for environment, rural and marine affairs of Spain and newly elected president of United Nations Environment Programme (UNEP)'s Governing Council.

The ministers called on UNEP to support countries keen to operationalize such a transition and to play a key and "active" role in putting the challenges, opportunities and strategies towards a green economy firmly on the agenda for the landmark meeting.

The UN Conference on Sustainable Development 2012, or Rio+20, also needs to address how the world can better manage and govern the environment including by evolving and strengthening the institutions responsible.

The ministers responsible for the environment, who have been meeting this week at UNEP headquarters, expressed concern that the overall efforts of UN and nations in respect to the "environmental pillar" of sustainable development remained weak, underfunded and fractured.

In their summary of discussions, released Friday at the close, many delegates said countries needed to move beyond pinpointing shortcomings and to focus on a real reform agenda in the run up to Rio+20.

The summary will form a key input of ministers responsible for the environment into the year long preparations for the Rio+20 conference, which is scheduled for early June 2012.

"The world is again on the road to Rio, nearly 20 years after the Earth Summit that has defined humanity's response to sustainable development over the intervening years," Achim Steiner, UN under-secretary-general and UNEP executive director, said.

"In Nairobi this week, the world's ministers responsible for the environment have underlined their leadership and their determination to make Rio+20 a success by articulating a forward- looking agenda - one that reflects the realities of a new century and the urgency of bringing together the three pillars of sustainable development: economic, social and environmental," he said.

Close to 100 ministers and over 130 countries attended this week's UNEP Governing Council/Global Ministerial Environment Forum alongside members of civil society, the private sector and scientific bodies.

The two themes - the Green Economy and International Environment Governance (IEG) - reflect the two major themes of the Rio+20 conference which are the green economy in the context of sustainable development and poverty eradication and the institutional framework for sustainable development.

In support of these discussions, UNEP presented a pivotal new report on how a transition to a green economy might be achieved by countries.

The report suggests that with the right public policies, an investment of 2 percent of global GDP into 10 key sectors can grow the global economy over the coming 40 years, boost employment overall and keep humanity's footprint within ecological boundaries.

The report which was presented late Thursday underlined that a green economy transition is as relevant to developing countries as it is to developed countries and that the precise complexion of such a transition needs to reflect the individual circumstances of nations.

Among the final decisions made Friday, governments also requested UNEP in partnership with other UN agencies, to develop a 10-year framework of programmes aimed at boosting sustainable consumption and production across societies.

The initiative, which also reflects the ideas and aims of the green economy, will be further key input towards the success of Rio+20.

"This week ministers also engaged on the complex issues of IEG - how do we strengthen the maze of institutional and financial arrangements relating to the environment, globally and nationally in order to effect real, tangible and transformational change that decouples growth from degradation?" Steiner said.

"As a result of this Governing Council, the direction for that reform has been given a greater focus, new momentum and taken on a greater sense of urgency which will inform the discussion, debate and finally the outcome of Rio+20 next year," added Steiner. Concluding the meeting and considering her new role as president of UNEP's Governing Council, Rivero said UNEP has been strengthened thanks to the fruitful debate on the two main themes addressed at the ministerial consultations. "I intend to foster the active and effective participation of all relevant stakeholders and particularly civil society, NGO's, Trade Unions and Women during my tenure," Rivero said.

The Governing Council also adopted some 17 key decisions across UNEP's Programme of Work. These included assessments of short- lived climate forcers such as black carbon, methane, fluorinated gases and tropospheric or "low-level" ozone. The ministers said while emissions of carbon dioxide remain the central and over-arching challenge, science is indicating that these other so-called non-CO2 pollutants are currently contributing significantly to climate change.

"Fast action to phase them down could not only assist in reducing temperature rises over the next half century and reduce melting in the Arctic, but could provide multiple, green economy benefits across areas such as agriculture and air quality improvements," they said.

During the meeting, governments requested UN agencies to convene the first plenary of the Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services (IPBES).

Another decision agreed late Thursday also supports improved cooperation between developing countries on biodiversity as part of a new more than 10-year initiative.

Governments requested UNEP to organize a major international meeting on how to accelerate cuts in pollution and wastes to seas and oceans under its Global Programme of Action for the Protection of the Marine Environment from Land-based Activities. They also requested that UNEP works more closely with bodies such as the International Maritime Organization in order to catalyze action to reduce marine pollution from shipping.

Governments also requested UNEP to work with the UN's Office for the Coordination of Humanitarian Affairs in order to prepare a report on how the UN as a whole can better respond to environmental emergencies from droughts and floods to chemical and other spills.