Leaders of the Group of Eight industrialized nations agreed on the first day of their summit to seek an 80 percent cut in their greenhouse gas emissions by 2050 compared with 1990 or more recent years.

The climate accord reached Wednesday in L'Aquila, Italy, also calls for a commitment by the developing world, saying that emerging economies need to undertake quantifiable actions to reach a global reduction of 50 percent in the same time frame.

But the Major Economies Forum on Energy and Climate, or MEF, a multinational framework that groups major polluters, including China and India, has already failed to lay the groundwork for a breakthrough at the working level before its leaders' meeting Thursday, casting doubt on the effectiveness of the G8 accord.