UN Secretary-General Ban Ki-moon called on Thursday for swifter work on a new climate treaty to fend off what he said could be economic disaster with a surge in sea levels of up to 2 metres (6.5 ft) by 2100.

"We will pay a high price if we do not act," he told a 155-nation climate conference in Geneva of negotiations on a new United Nations deal to combat global warming that is due to be agreed in December in Copenhagen.

"Climate change could spell widespread economic disaster," Ban said, adding the solution was greener growth.

"By the end of this century, sea levels may rise between half a metre and two metres," he said. That would threaten small island states, river deltas and cities such as Tokyo, New Orleans or Shanghai, he said.

His sea level projection is above the range of 18 to 59 cms (7-24 inches) given in 2007 by the UN's own panel of experts.

Their estimates did not include the possibility of an accelerated melt of vast ice in Antarctica or Greenland.

He said greenhouse gas emissions were still rising fast despite promises to rein in growth. "Our foot is stuck on the accelerator and we are heading towards an abyss," he said.

"We cannot afford limited progress. We need rapid progress," in the climate negotiations, he said.

He said he had seen the impacts of change on a trip this week to see thinning Arctic sea ice off Norway.

Ban said he hoped a summit of world leaders he will host in New York on September 22 would give a new push towards Copenhagen.

"Political support for climate action is growing. But still not fast enough," he told an audience including about 20 leaders, mostly of developing nations such as Tanzania, Bangladesh and Mozambique, and ministers from up to 80 nations.

Leaders of developing nations urged more aid and green technologies. Ethiopia's President Girma Woldegiorgise said African nations were suffering from climate change even though they had done almost nothing to cause the problem, blamed mainly on greenhouse gas emissions from burning fossil fuels.

In the Copenhagen talks, developing nations want industrialised nations to promise deeper cuts in greenhouse gas emissions for 2020 and come up with more aid. But rich nations want clearer promises from the poor that they will also act.

The Geneva August 31-September 4 conference, gathering about 1,500 delegates, formally approved a goal of a new system to improve monitoring and information of the climate to help everyone from farmers to energy investors.

Delegates said a "Global Framework for Climate Services" would help the world adapt to changes such as more floods, wildfires, droughts, rising seas or more disease.

Under the plan, the UN's World Meteorological Organization would set up a task force of advisers who would then have a year to report with proposals about how it would work in sectors such as health, energy and agriculture.

Farmers, for instance, want to know how a projected thaw of Himalayan glaciers will disrupt water flows in rivers in India or China. Investors in wind farms can benefit from information on future wind patterns, rather than historical data.

Among examples, experts say better forecasting of rains in Botswana, for instance, is allowing doctors to deploy anti-mosquito nets to head off outbreaks of malaria before the insects appear.

The Geneva talks are the third world climate conference. Meetings in 1979 and 1990 helped lay the foundations for more scientific observations and a UN 1992 Climate Convention. - Reuters