Canadian rules limiting industrial greenhouse gas emissions won't even be developed until next year and will not take legal effect for up to six years, to match a proposed U.S. timetable, Environment Minister Jim Prentice said Thursday.

It's a far cry from the Conservative government's former "Made in Canada" climate change plan that was supposed to come into force just over six months from now.

It further calls into question Prime Minister Stephen Harper's stated target for reducing Canada's greenhouse gas emissions by 20 per cent from 2006 levels by 2020.

Prentice, speaking to reporters by conference call from London, said emissions cuts for what he termed the "pure industrial sector" — the largest emitting sector representing about 30 per cent of total Canadian emissions — will likely have to be harmonized with U.S. rules in order to protect Canadian jobs and investments.

He noted the current American timetable won't see anything taking effect until between 2012 and 2016.

"In the case of any regulations we bring into law in Canada, we will ensure that careful attention is paid to what our major trading partner is doing, what their regulations are and when their regulations come into law," Prentice said, speaking after a week of meetings that took him to Denmark, France, Norway and Britain.

"And at this point what's under discussion in the United States starts in 2012."

Detailed regulations were supposed to be published last year and come into force on Jan. 1, 2010.

The plan by former environment minister John Baird superceded an earlier Conservative policy, announced in 2006 by yet another Tory environment minister, that was also supposed to start reducing emissions by 2010.

"A government that is willing to wait six or more years after taking office before regulating emissions clearly doesn't understand the threat or the urgency of global warming," Matthew Bramley, climate change director at the Pembina Institute, said Thursday by email.

Prentice said that before the next round of international climate change talks in Copenhagen this December, the government will make public "a full suite of policies that relate to all sources of greenhouse gas emissions."

But the "very complex" regulations required to enact the policies will require another year to develop, he said.

New auto emission standards are slated to come into force Jan. 1, 2011.

Bramley noted this will be the fourth Canadian climate change plan in the last decade, including the Liberal plan that was scrapped by the Tories when they came to office in January 2006.

"If all we have to take to the Copenhagen negotiations this December is yet another plan — but without the actual regulations to implement it — Canada's credibility is going to remain stuck at rock bottom," he said.

Bramley noted that most experts who've examined the Conservatives' 20 per cent by 2020 reduction target found little evidence it was achievable by the means proposed, premised on reductions starting in 2010.

"So with a further delay of two years or more in regulations taking effect, it's even less likely that Canada would meet the target the government has committed to," said the climate change campaigner.

Prentice, in a followup interview with The Canadian Press, said it's "a fair question" how a delayed enforcement timetable will impact the 2020 target, but the goal remains unchanged. "That continues to be our objective."