CANCUN - UN Secretary-General Ban Ki-Moon, trying to revive long-stalled climate talks, told world environment ministers yesterday he was "deeply concerned" that many years of negotiation had proven largely fruitless.

"The pace of human-induced climate change is accelerating. We need results now, results that curb global greenhouse emissions," Ban declared at the opening of high-level talks at the annual UN climate conference.

In the two-week session's final days, environment ministers would seek agreement on knotty side-issues in coping with global warming.

"Nature will not wait while we negotiate," he said. "Science warns that the window of opportunity to prevent uncontrolled climate change will soon close."

UN environment chief Achim Steiner said voluntary pledges would, at best, offer the world limited protection against serious damage from shifts in climate.

Despite evidence of growing impacts, and scientists' warnings that temperatures will rise sharply in this century, nations have made little progress over the past decade toward a new global pact on emissions cuts to replace the 1997 Kyoto Protocol.

Instead, environment ministers will focus on secondary tools for confronting global warming, laying the groundwork, for example, for a "green fund" of US$100 billion a year by 2020.

Financed by richer nations, the fund would support poorer nations in converting to cleaner energy sources and in adapting to a shifting climate that may damage people's health, agriculture and economies in general.

Negotiators hope to agree on a mechanism giving poorer countries easier access to green technology.

Many negotiators want the voluntary targets proposed in last December's Copenhagen accord "anchored" more formally in a final Cancun document - which will be subject to back-room haggling in the coming days.

- AP