Leaders of rich and developing nations failed to overcome differences on tackling climate change but agreed on the need for major emissions cuts, as the G8 summit concluded in Japan on Wednesday.

The talks between the Group of Eight leading industrialized nations and eight major developing economies on the northern Japanese island of Hokkaido came a day after the G8 adopted a statement calling for a 50% cut in greenhouse gas emissions by 2050.

Tuesday''s statement from the leaders of Britain, Canada, France, Germany, Italy, Japan, Russia and the United States met with harsh criticism from environmentalists for its ambiguous wording and lack of specific mid-term targets.

The meeting between the 16 leaders, including Chinese President Hu Jintao, Indian Prime Minister Manmohan Singh, and Brazilian President Luiz Inacio Lula da Silva, also addressed rising fuel and food prices, and their impact on the world economy.

Major differences remained on climate change, with China and India refusing to sign up to the G8''s emissions goal. The Chinese leader told the meeting that rich nations must take the initiative in curbing emissions, and support developing economies'' efforts by providing clean technology and funding.

However, the leaders agreed in their statement that "climate change is one of the great global challenges of our time," and that "Our nations will continue to work constructively together to promote the success of the Copenhagen climate change conference."

The statement called for medium-term emissions cuts, but omitted any mention of numerical targets.

The leaders declared their support for United Nations negotiations on agreeing a new international deal to replace the Kyoto Protocol, set to expire in 2012.