The three-day forum of environment ministers and officials from 150 countries also adopted a "Jeju Initiative" aimed at identifying the world's best water conservation practices and endorsing them as examples for water-starved countries.
Klaus Toepfer, executive director of UNEP, called the initiative an "important paper" but conceded "we cannot simply have a smile on our face."
He said UNEP needs better funding, a complaint echoed by environmental groups in attendance. France has been pushing to make the U.N. program, which is voluntarily funded, a mandatory-funded higher-tiered U.N. agency with more authority.
Friends of the Earth, a Netherlands-based environmental group, was disappointed the summit didn't provide more time to talk about that campaign.
"It should have been combined with concrete steps forward on substantive issues," said Simone Lovera, the group's international campaign coordinator.
The U.N. Environment Program's budget last year was $48.9 million, not enough to take on such diverse matters as global warming, overfishing, deforestation and water shortages, she said.
Earlier Wednesday, delegates approved a measure to have scientific teams research links between regional conflicts and water shortages, soil degradation and pollution.
Identifying the links between environment degradation and war could serve as an early warning system, letting policy makers know that if certain environmental problems crop up, they could spur political tensions, UNEP spokesman Nick Nuttall said.
It is commonly assumed by conservationists that environmental degradation can spike tensions and possibly trigger conflict. Problems are often thought to stem from environmental refugees who flee floods, water shortages, dust storms or pollution, and venture into new areas where they are not always welcome.
But more research is needed because the links aren't well understood.
"One key question is whether a declining environment automatically triggers instability and conflict," Toepfer said in a UNEP publication released at the summit. "There are cases where conflict has not occurred despite such a decline, and others where it has. So it may be that a degraded environment is a trigger among a suite of factors."
The discussions in Jeju, a South Korean resort island, formed the basis for talks next month in New York with the U.N. Commission on Sustainable Development.
That meeting will assess progress toward the United Nation's target of halving the number of people with no access to safe drinking water or basic sanitation by 2015.
Globally, about 1.1 billion people lack access to safe drinking water, while another 2.4 billion lack access to basic sanitation, UNEP says. Nearly 5,000 children die every day from diseases caused by a lack of water, it says.
Supplying safe water is increasingly difficult because the world population is growing so fast, by about 77 million people a year, UNEP says.
By Hans Greimel