The Group of Eight leaders today set a goal of cutting greenhouse gas emissions by 50 percent by 2050, but environmental groups said that may not be enough and that the plan lacks needed midterm targets.

The heads of Canada, France, Germany, Italy, Japan, Russia, the U.K., and the U.S. are in Japan this week for their annual forum.

"Confirming the results of last year's summit in Heiligendamm is hardly a remarkable outcome," said Kim Carstensen, director of the WWF Global Climate Initiative.

"So little progress after a whole year of minister meetings and negotiations is not only a wasted opportunity, it falls dangerously short of what is needed to protect people and nature from climate change."

The G8 leaders acknowledged the need for midterm goals and said they look forward continuing the discussions among the major economies and in the United Nations Framework Convention on Climate Change negotiations over the coming months.

The next U.N. Climate Change Conference will be held at the end of 2009 in Copenhagen, Denmark, where a successor to the Kyoto Protocol is expected to completed.

The WWF said global emissions need to be cut by much more than 50 percent by 2050 to avoid the worst impacts of climate change.

The conservation organization said global emissions have to peak and decline in 10 to 15 years and rich nations must reduce emissions by 25 percent to 40 percent by 2020.

Daniel Mittler, a climate policy expert at Greenpeace International, said, "The G8 have failed the world again. While the Artic is melting, the G8 are postponing action."

Mittler noted that the World Bank Climate Investment Funds that the G8 is supporting do not exclude coal.

"The G8's 2050 vision will be a nightmare, unless the world ends its fossil fuel addiction and starts an energy revolution based on renewable energies and energy efficiency – now!"

On the controversial issue of biofuels, the G8 said it will work to develop science-based benchmarks and indicators for biofuel production and use.

The leaders also said they are committed to continuing research and development of second generation biofuels made from non-food plant materials and inedible biomass.