Leaders of major developing countries called Tuesday for the world's wealthy nations to do far more to battle climate change and to tackle rising food prices before they lead to a spiral of poverty and instability.

The leaders of China, India, Mexico, Brazil and South Africa said after a one-day summit in Japan that they expect the Group of Eight top industrialized nations to take the lead in global efforts to cut back emissions of greenhouse gases and provide more aid to the developing world to help it cope with climate change.

The leaders, including Chinese President Hu Jintao and Indian Prime Minister Manmohan Singh, said it was "essential" for the developed world to spearhead the fight against climate change because they are major contributors to the problem and have the economic strength to adopt sweeping changes.

They called on the G-8 countries to reduce their greenhouse gas emissions by up to 45 percent by 2012, compared with their 1990 levels, and by up to 95 percent by 2050.

That is far more ambitious than the G-8 countries — the United States, Japan, Britain, France, Germany, Russia, Italy and Canada — have been willing to commit to.

In a statement earlier Tuesday at its own summit, the G-8 endorsed halving world emissions of greenhouse gases by 2050, but did not set a base year and stressed the need for all major countries — including China and India — to join the effort to stem the potentially dangerous rise in world temperatures.

The developing countries' leaders have resisted that approach, saying they are the most vulnerable to natural calamities posed by global warming and will have more trouble adapting their economies to the changes needed to reduce gas emissions.

"For developing countries, adaptation is of cardinal importance, particularly given their vulnerability, limited capacity and inadequate means," they said in a joint statement after the daylong summit in Sapporo, just north of where the G-8 leaders are meeting.

The two groups — along with Indonesia, South Korea and Australia — were to meet Wednesday to further discuss the issue.

The developing countries' leaders also said they intend to focus on the recent rise in food prices when they join Wednesday's summit with the G-8.

"The rise in global food prices poses a new challenge to the fight against poverty and hunger," they said. "The world produces enough food, but not enough people have access to it. We call upon the international community to devise better ways and means of producing and distributing food."

The statement urged the G-8 to increase emergency aid "at an early date."

Chinese president Hu said the causes of rising food prices are "multifaceted and complex" and said it is unfair to blame the nations with the world's largest populations for the problem.

Some countries — notably India — have imposed restrictions on food exports, exacerbating shortages in importing countries.

Hu didn't elaborate, but he noted that the food crisis is most acutely felt in the developing world.

"We five countries are all major grain producers and consumers," he said, adding that they need to increase cooperation in such practical areas as planting, disease and pest prevention and grain reserves.

The five countries represented at Tuesday's summit account for 42 percent of the world's population and 12 percent of the world's GDP.