Group of Eight environment ministers called on Monday in a statement for rich nations to take the lead in a global effort to at least halve greenhouse gas emissions by 2050.

Ministers and senior officials from the Group of Eight wrapped up three days of talks aimed at setting the stage for their leaders' annual summit, to be held in July in the northern Japanese mountain resort of Toyako.

Last year's summit in Germany agreed to "seriously consider" reducing greenhouse gas emissions, which are blamed for warming up the planet, by at least half by 2050.

"Strong political will was expressed to go beyond this agreement and reach agreement on a shared vision of a long-term global goal at the G8 Toyako summit," said a chairperson's summary issued by host Japan.

"It was noted that in order to halve global (greenhouse gas) emissions, developed countries should take the lead in achieving a significant reduction," it said.

The Kyoto Protocol requires rich countries to slash greenhouse gas emissions by an average of five percent by the end of 2012 from 1990 levels.

The United States is the only major industrial country to reject Kyoto, with US President George W. Bush arguing that it is unfair not to include developing states.

Last year's agreement at the G8 summit in Germany was seen by many environmentalists as a step forward but was also criticised for not requiring binding cuts and being ambiguous about the base year for cuts.

The G8 is made up of Britain, Canada, France, Germany, Italy, Japan, Russia and the United States.

Japan hopes to use the G8 conference to shape a new treaty on global warming to cover the period after Kyoto's obligations expire at the end of 2012.

It has pushed for a so-called "sectoral" approach in which standards are set for each industry. The idea has met resistance from some developing nations, which see it as a bid to force them to adopt costly new technology.

In a possible sign of a softening in Japan's position, the final statement said that "sectoral approaches would be used to set national targets, not as a substitute for them."

AFP