TOYAKO, Hokkaido — Five of the top developing nations on Tuesday denounced the Group of Eight's qualified proposal to halve global greenhouse gas emissions by 2050, saying the industrialized powers should slash their own emissions by up to 95 percent below 1990 levels.

The five nations — Brazil, China, India, Mexico and South Africa — issued a statement titled the G-5 Political Declaration ahead of a meeting scheduled Wednesday between the G8 leaders and the heads of the "outreach" nations on climate change.

"It is essential that developed countries take the lead in achieving ambitious and absolute greenhouse gas emissions reductions in accordance with their quantified emissions targets under the Kyoto Protocol after 2012, in the range of at least 25 percent to 40 percent for emissions reductions below 1990 levels by 2020, and, by 2050, between 80 percent and 95 percent below those levels, with comparability of efforts among them," the statement read.

The G-5 also warned the G8 that any pact on the part of the developing countries toward long-term targets for reducing greenhouse gas emissions will first require many guarantees from the industrialized nations.

"Negotiations for a shared vision on long-term cooperative action, including a long-term goal for greenhouse gases emissions reductions, must be based on an equitable burden sharing paradigm that ensures equal sustainable development potential for all citizens of the world, and takes into account historical responsibility and respective capabilities as a fair and just approach," the statement added.