Harper's tone changed in December after the Liberals elected a former environment minister as leader. Harper replaced his own environment minister and promised to do more.

In the last week alone Ottawa announced more than C$2 billion (US$1.7 billion) in funding over the next 14 years for projects to make houses more energy-efficient, develop renewable energy and protect a British Columbia forest.

The Liberals complained that the initiatives were very similar to ones they themselves had proposed.

"You can't blame Canadians for greeting Prime Minister Stephen Harper's sudden conversion to environmentalism with a bit of skepticism," said the Montreal Gazette, part of a newspaper chain generally sympathetic to the Conservatives.

"The recent flurry of Conservative environment measures has the feel of electioneering," the Gazette said in an editorial.

Harper's power base is in the western province of Alberta, where emissions of greenhouse gases are set to soar as companies exploit the oil-rich tar sands. Critics say Harper would never do anything to upset Calgary, the economic capital of Alberta, where many energy companies are based.

"Public skepticism is so great that Harper could spent C$20 billion (US$17 billion) a year on the environment and it wouldn't make a difference," said one senior Liberal strategist.

"The only way he could make a breakthrough is if he did something so radical that it caused him to be burned in effigy in Calgary," the strategist told Reuters.

Harper, who says Canada cannot meet the targets for cutting emissions of greenhouse gases laid out by the Kyoto protocol on climate change, clearly did not expect the environment to start dominating domestic politics so rapidly.

The topic barely featured in the 2006 election but now dominates the headlines. Environmental groups say Harper can only show he is serious by committing to stick to Kyoto.

"You could ask when we're going to cut them some slack. Well, the reality is when we start to see meaningful change and meaningful action," said Andrew Male of Greenpeace Canada.

"For groups like ours it doesn't really matter whether he (Harper) cares or not, it's whether he does it or not."

Harper is not helped by a rather reserved personal style which makes it hard for him to appear excited about any topic.

Jeffrey Simpson, a columnist for the Globe and Mail, wrote that Harper had problems with the environment because his government's style was to roll out green programs "without a tinge of emotional commitment to what is actually being said".

Harper's team dismisses the suggestion it is playing green to win votes.

"People will just have to judge us at the time of the election: did we do enough? I don't think you can ever do enough on the environment but did we do enough to at least earn their recognition or their appeasement to give us the chance to do more?" one senior aide told Reuters.

Last year, former Conservative Prime Minister Brian Mulroney -- who when in office was instrumental in pushing through a deal with the United States to cut acid rain -- was named Canada's greenest ever leader.