The World Summit for Sustainable Development (WSSD), to be held in Johannesburg from August 26 to September 4, is billed as the largest U.N. meeting in history with more than 100 world leaders and 60,000 delegates.

Annan said world leaders could produce ambitious but achievable action plans to improve the lives of human beings while protecting the planet.

"These are five areas in which progress would offer all human beings a chance of achieving prosperity that will not only last their own lifetime, but can be enjoyed by their children and grandchildren too," Annan said in a statement.

The Johannesburg summit is meant to build on the Rio de Janeiro Earth Summit in 1992, the first environmental summit after the Cold War. Rio's agreements included pledges to fight global warming in a deal since undermined by a U.S. pullout.

Johannesburg faces criticisms that it is trying to solve too many of the planet's problems in one go - an almost inevitable recipe for failure.

But Annan said the environment too often takes a back seat to other concerns such conflicts, globalisation and terrorism.

"At discussions on global finance and the economy, the environment is still treated as an unwelcome guest," he said.

Agreement is yet to be reached on the agenda for the Johannesburg summit after the collapse of preparatory talks in Bali, Indonesia, in June.

Annan said global leaders should discuss provision of water access to a billion people who lack clean drinking water. He also wanted to see fruitful discussions on provision of energy to two billion people who lack modern energy services through promoting renewable energy and reducing over-consumption.

He urged them to address the effects of toxic and hazardous materials, reduction of air pollution which he said killed three million people every year, and lower the incidence of malaria.

"In Johannesburg, we have to catch up. Together, we will need to find our way towards a greater sense of mutual responsibility," Annan said.