A comment by a prominent Toronto NDP candidate Friday on how Canada's emissions targets might affect Alberta's oilsands touched off a political storm on the weekend, with the other parties and one provincial politician chiming in.

Linda McQuaig, a well-known author and journalist and the NDP candidate for the riding of Toronto Centre, told a panel discussion on CBC News Network's Power & Politics that for Canada to meet its climate change targets, "a lot of the oilsands oil may have to stay in the ground."

The remark is in line with views expressed by scientists in recent years. A 2009 paper in the journal Nature by researchers from Oxford University and elsewhere calculated that more than half the planet's proven oil, gas and coal reserves would have to be left in the ground for the world to keep global warming to below two degrees Celsius — considered a critical threshold to avoid massive climate disasters.

"Not even the oil companies think they are going to get every last barrel out of the tar sands," Greenpeace climate campaigner Keith Stewart said Sunday.  

But that didn't stop McQuaig's comments from triggering a fierce backlash from Conservatives and Liberals.

A Calgary Conservative incumbent on the program with McQuaig accused the NDP of proposing a moratorium on the oilsands. Michelle Rempel also said it would kill jobs at a time of instability in the oil sector.

Candidates debate the debate11:48

Conservative Leader Stephen Harper volunteered his reaction in Ottawa on Sunday as he proposed new restrictions on travel to areas of "terrorist activity" should he be re-elected.

"That is the NDP's not-so-hidden agenda on development," Harper said of McQuaig's comments, without any prompting by reporters covering the event.

"The NDP is consistently against the development of our resources and our economy. That's why they have been a disaster wherever they've been in government and why they would wreck this economy if they ever got in, and why they must never get into power in this country."

Alberta Opposition Leader Brian Jean, whose Fort McMurray riding is in the heart of the oilsands, said Saturday that McQuaig's comments were "deeply concerning" and he called on the province's New Democratic premier, Rachel Notley, to stand up to the federal NDP.

NDP Leader Tom Mulcair has in the past enthusiastically called a west-to-east oil pipeline for pumping Alberta's oilsands crude to tidewater a "win-win" which will mean better prices for the producers, and therefore more royalties for the producing provinces.

He said it must include a rigorous, transparent environmental review process and legislation to force oil companies to pay for the pollution they create, including any increase in greenhouse gas emissions.

McQuaig later posted on Twitter that the NDP position is that sustainable development means stronger environmental reviews, which she says the government of Stephen Harper has undermined.

"NDP policy is sustainable development, overseen by strong enviro review process which Harper has destroyed," McQuaig tweeted on Friday afternoon.

'It shouldn't be treated as heresy to ask what is a reasonable limit within the carbon budget that Stephen Harper promised the world we'd live within.' -  Keith Stewart, Greenpeace campaigner

The federal NDP campaign office later released a statement from the party's natural resources critic, who said McQuaig's comments weren't about the party's position on the oilsands, but rather the possible constraints the industry would face under emissions-reduction targets.

"Ms. McQuaig was not referring to NDP policy, rather she was referring to what one particular international report has said that might be necessary under Stephen Harper," said Malcolm Allen in the emailed statement.

Greenpeace's Stewart said that, in any case, it's not unreasonable to wonder what will happen to the oilsands, given that even the Conservatives have promised to wean Canada off of all fossil fuels by the year 2100.

"It shouldn't be treated as heresy to ask what is a reasonable limit within the carbon budget that Stephen Harper promised the world we'd live within," he said.

Alberta politicians weigh in

Cheryl Oates, a spokeswoman for Notley, said the provincial NDP's position on the oilsands remains the same.

"We've always been committed to the sustainability of the energy industry, which provides good, mortgage-paying jobs, and nothing has changed," Oates said.

Other politicians chimed in too.

Liberal Leader Justin Trudeau said McQuaig's remarks, and Harper's reaction, show that both the NDP and the Conservatives hold "extreme positions" on the economy and the environment.

Rempel, meanwhile, claimed Mulcair is planning to shut down Alberta and Canada's resource sector and said the comments couldn't be merely put off as a candidate addressing a hypothetical scenario.

"This isn't just some candidate," Rempel said of McQuaig. "This is a candidate that Mulcair is out on the record calling brilliant and articulate and saying that she'd be on the front bench with him."

With files from CBC News