France and Brazil joined forces on Saturday to press the United States and China to make significant concessions at next month's climate change summit in Copenhagen.
In a joint document, French president Nicolas Sarkozy and president Luiz Inacio Lula da Silva of Brazil urged rich industrialised countries to cut emissions of greenhouse gases by at least 80% from their 1990 levels by 2050.
They called on emerging countries to seek low carbon growth and to take steps to slow the rate at which their greenhouse gas emissions rise by 2050, with "substantial" financial help from richer countries.
"We will not accept a situation where we agree these measures and other countries say: 'We'll see tomorrow'," Sarkozy told a joint news conference.
"This is a collective responsibility."
Just before the meeting in Paris, Brazil pledged to cut its greenhouse gas emissions by between 36.1% and 38.9%, largely by controlling deforestation in the Amazon region, a decision praised by Sarkozy.
Lula told reporters the document signed with Sarkozy was "more than a declaration of intent, it is a climate bible" and the two leaders said the United States and China had to show more boldness in accepting commitments at Copenhagen.
US president Barack Obama and Chinese leader Hu Jintao, whose two countries are the world's biggest emitters of greenhouse gases, are due to meet next week to seek common ground on climate change.
But as the deadline for the December 7-18 climate change meeting in Copenhagen approaches, Sarkozy and Lula, who will both be at Copenhagen, said they could not be allowed to settle matters between themselves.
"We cannot allow president Obama and president Hu Jintao to celebrate an accord which only takes the economic realities of their two countries into account," Lula said.
He said he would telephone Obama to discuss the joint Franco-Brazilian initiative as part of a diplomatic offensive in which he and Sarkozy will try to drum up support before the Copenhagen summit.
Sarkozy said he would not accept a "minimal" accord at Copenhagen and would insist on firm commitments from the world's biggest carbon emitters.
"You know the friendship that France has for the United States of America and the confidence I have in president Obama, but the world's biggest economy has to face up to its responsibilities," he said.
Some 190 nations will meet in Copenhagen, but talks so far have been clouded by disputes between rich and developing nations and hopes have faded for a legally binding framework to stave off dangerous levels of global warming that scientists say could bring rising seas, more droughts, heatwaves and floods.
Sarkozy, who will discuss the initiative with German chancellor Angela Merkel on Thursday, said he hoped to travel to Brazil and Africa and would attend the Commonwealth summit in Trinidad and Tobago at the end of the month to press his case.
