Leaders of the eight industrialized nations reiterated their willingness to share with all countries the goal of achieving at least a 50 percent reduction of global emissions by 2050.

They made the remarks in a declaration, Recovery and New Beginnings, issued on Saturday when the two-day G8 summit concluded at Muskoka, Ontario, Canada.

Canadian Prime Minister Stephen Harper speaks at his closing news conference at the G8 Summit at the Deerhurst Resort in Huntsville, Ontario, Canada, June 26, 2010. (Xinhua/Host Photo/Francis Vachon)

But the declaration was criticized by some environment conservation organizations.

The G8 leaders said that as agreed in L'Aquila, Italy in 2009, they recognized the scientific view that the increase in global temperature should not exceed 2 Celsius degrees compared to pre- industrial levels.

"Achieving this goal requires deep cuts in global missions," they said."This global challenge can only be met by a global response, weill cooperate to that end."

The leaders also supported a goal of developed countries reducing emissions of greenhouse gases in aggregate by 80 percent or more by 2050, compared to 1990 or more recent years.

"Consistent with this ambitious long-term objective, we will undertake robust aggregate and individual mid-term reductions, taking into account that baselines may vary and that efforts need to be comparable,"they said.

The G8 leaders also urged the major emerging economies to undertake quantifiable actions to reduce emissions significantly below business-as-usual by a specified year.