Where Canada stands on this major rift remains a mystery leading up to the G8 meetings in Heiligendamm, Germany, beginning June 6.

The three days of meetings are widely regarded as a bellwether for the success of the United-Nations-led efforts to start a second phase of the Kyoto Protocol on climate change. Talks on that second phase, which would include countries such as India and China, begin December in Bali.

International news agencies reported Friday that the United States was balking at the text of a final statement from the meeting of the group of eight leading industrial countries that was being drafted by representatives from the various countries including Canada.

The United States is opposed to any commitment that mentions targets or a date for reducing global greenhouse-gas emissions.

Washington also wants removed a statement of support for carbon trading markets, and will not support a line that reaffirms the negotiating mandate of the Bali talks for an international agreement with a deadline of 2009.

Environment Minister John Baird was asked about the controversy yesterday, but did not specifically comment on the U.S. position. He said he saw Canada acting as a "bridge" between the divergent opinions.

"We need a genuine effort to get the United States, China, India to join with Canada and other European countries on worldwide efforts to reduce greenhouse-gas emissions," Mr. Baird said in Toronto.

The minister also said Canada supports the European-backed idea of a 50-per-cent reduction in greenhouse-gas emissions by 2050, although he uses a much different base year for the reduction: 2006 instead of 1990.

He has said in the past that Canada supports the Kyoto process and the role in it of the United Nations.

A spokesman for Foreign Affairs Minister Peter MacKay, whose department is working on the drafting of the G8 declaration, would not comment.

Louise Comeau of the Vancouver-based Sage Centre's climate project interpreted Mr. Baird's remarks about Canada acting as a bridge as meaning the Conservative government will inevitably help water down G8 declaration by insisting Washington's views be included.

She said the biggest threat posed by the United States is to the role of the United Nations as the main forum for striking an international agreement. She wants Canada to come out forcefully in defence of the UN process.

"There's nothing unreasonable in the German proposals and Canada should be supporting them," she said.

Liberal Leader Stéphane Dion sent an open letter to Prime Minister Stephen Harper on the weekend, urging him to take a hard stand against Washington's position.

"I am deeply troubled by Canada's silence in the face of recent reports that U.S. President George Bush is seeking to weaken the proposed G8 Declaration on Climate Change and Energy Efficiency," he wrote.

"I am writing to urge you to recognize the moral imperative of urgent action, to seize the mantle of international leadership, and to speak out forcefully against the United States' efforts to dilute the global action plan. We must be ambitious, because failure is not an option."

German Chancellor Angela Merkel, host of the G8 Summit, has already dampened expectations of consensus. "As the G8 we must come to a common understanding on how we can fight climate change. But as I stand here today, I am not sure that we will manage this in Heiligendamm," she said in the German parliament last week.