Two weeks before the start of a global conference on sustainable development in Rio de Janeiro, the United Nations is warning that progress has stalled on key environmental goals the world's nations have set for themselves, like tackling climate change, combating desertification and protecting biodiversity.

"The world continues to speed down an unsustainable path despite over 500 internationally agreed goals and objectives to support the sustainable management of the environment and improve human well-being," the United Nations Environmental Program (UNEP) said when it released its Global Environmental Outlook Wednesday.

The world has made progress on only four out of 90 of the most pressing environmental goals and objectives agreed upon as part of the Millennium Development Goals and other international pacts, the UNEP said.

The four areas where the UN agency found significant progress are:

• Reducing substances that deplete the ozone layer.
• Removing lead from fuel.
• Increasing access to improved water supplies.
• Boosting research on ways to reduce pollution of the marine environment.

Little to no progress was made on climate change-related goals such as limiting the increase in average global temperature to less than two degrees above pre-industrial levels or in areas such as revitalization of depleted fish stocks, protection of biodiversity and the combating of desertification.

A sea star eating into a washed-up dungeness crab killed by a recurring dead zone of oxygen-depleted water on the coast of Oregon state in 2004. Only 13 of the world's 169 coastal dead zones are recovering, a UN report found. (Jane Lubchenco/Oregon State University/Associated Press)

"The luxury of develop first, clean up later…that age, that century is gone," said Achim Steiner, UN under-secretary general and UNEP executive director.

In some areas, such as wetland and coral reef protection, nations have actually regressed, said the UNEP report, the fifth such overview in 15 years. Coral reefs are at greater risk of extinction than any other living organism and have deteriorated by 38 per cent since 1980, the report found.

Overall, the world is failing to stem the loss of biodiversity, with about 20 per cent of vertebrate species under threat and some natural habitats shrinking by more than 20 per cent since the 1980s.

"We have failed," said Elizabeth Thompson, executive co-ordinator for the upcoming Rio conference, dubbed Rio+20. "We have not properly mainstreamed the issue of sustainable development as a way of living, doing business. That is the overall reason why we have not made the kind of progress that we should have."

Some progress on protected areas

The world has made some progress in granting protected status to parks and other natural sites but still remains short of the goal set for 2020, which aims to see 17 per cent of the world's land and 10 per cent of its marine area protected. Currently, only 13 per cent of land and 1.6 per cent of marine area is protected.

Some progress has been made to slow deforestation since the 1990s, when about 16 million hectares of forest were being lost a year. Between 2000 and 2010, that had decreased to 13 million hectares a year.

Water is distributed to people in El Srief in Sudan's North Darfur region, where the nearest water point is 15 km away and women have to spend six hours a day collecting water for their families. Water scarcity and quality remain major problems in many parts of the world. (Albert Gonzalez Farran/UNAMID Handout/Reuters)

Water quality and access to clean water remain some of the most pressing issues for many nations. By 2015, more than 600 million people will lack access to safe drinking water and more than 2.5 billion will still be without sanitation.

Water and life in the world's marine environments are faring no better. The number of coastal dead zones, large oxygen-depleted areas that can no longer support life, has increased, with only 13 out of 169 worldwide on their way to recovery.

The report found that 80 per cent of marine pollution is caused by land-based activities.

Data lacking

The UN agency acknowledged that there were many gaps in its data because it relies on statistics kept by individual nations, which don't always collect the relevant information or keep it up to date.

Among its recommendations was a more reliable system of maintaining data so progress can be accurately measured and smart decisions about environmental resources can be made.

It also recommended the setting of clear long-term targets attached to individual environmental goals in order to hold nations accountable. It pointed to the success of international agreements such as the Montreal Protocol, which helped nations meet their target on the halting of ozone depletion, and the MARPOL convention, which reduced marine pollution from ships.

A traffic jam in Jakarta, where about 25 million people live. Population growth combined with increasing consumption is the biggest challenge threatening any prospect of sustainable development in parts of Asia, Africa and the Pacific. (Enny Nuraheni/Reuters)

The report also produced regional outlooks. It singled out North America and Europe for their "unsustainable levels of consumption" and highlighted that North America lags behind other parts of the world when it comes to use of renewable energy.

The greatest threats for Asia, Africa and the Pacific are rapid urbanization and population growth coupled with increasing consumption, which are putting stress on already dwindling natural resources. Latin America and the Caribbean share similar worries.

Thompson said that the Rio conference is supposed to be a "transforming moment."

The Rio conference will take place in Brazil from June 20 to June 22 and will mark the 20th anniversary of the first Earth Summit, or United Nations Conference on Environment and Development, held in Rio in 1992.

Organizers have highlighted seven priority areas to be discussed at the conference: decent jobs, energy, sustainable cities, food security and sustainable agriculture, water, oceans and disaster readiness.

With files from Connie Watson