Brad Wall is lashing out at Ontario and Quebec for putting climate-change conditions on the Energy East oil pipeline, escalating an interprovincial battle over the controversial $12-billion project.

The Saskatchewan Premier argues the pipeline, which would ship 1.1 million barrels every day, would not significantly increase greenhouse gas emissions and accelerate global warming.

"Ontario and Quebec have announced a joint position that at best moves the goal posts for approval and at worst lays out new barriers," Mr. Wall wrote in an op-ed circulated to various newspapers Tuesday.

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"We first need to ensure that proposals to move oil across the country … are not subject to politically motivated unwarranted barriers."

Last week, Premiers Kathleen Wynne and Philippe Couillard laid out seven principles they say Energy East, which would be built by TransCanada Corporation, must satisfy in order to win their support. One condition is that its contribution to climate change be measured.

The two premiers want either proof that Energy East will not increase net greenhouse gas emissions, or a national strategy to cut emissions to compensate for the effect of increased oil-sands production.

Mr. Wall contends in his letter that any added emissions from Energy East, which would move oil from Alberta and Saskatchewan to refineries in Quebec and New Brunswick, would be offset by the refineries no longer having to import foreign crude.

Ontario Energy Minister Bob Chiarelli countered that, if Mr. Wall is correct – that Energy East would not increase greenhouse gas emissions – then he should have nothing to fear from the provinces assessing its effect on global warming.

"What is Brad Wall afraid of? We're saying [climate change] should be taken into account," Mr. Chiarelli said Tuesday.

"Taking it into account means: 'Let's find out whether there is, or there isn't [higher emissions.] And Brad Wall doesn't even want us to go that far," he said.

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So far, pipeline proponents have been collegial about the demands from Ms. Wynne and Mr. Couillard.

New Brunswick Premier Brian Gallant called them "fair and achievable," earlier this week; Alberta's Jim Prentice said he was prepared to see how they might be fulfilled. TransCanada has said it is still studying the requests and will work with Ontario and Quebec.

On Tuesday, one industry executive said the principles appeared to be reasonable standards the pipeline companies must meet to win government support in those provinces.

"That is not a roadblock; it's an invitation," Brenda Kenny, chief executive of the Canadian Energy Pipeline Association told The Globe and Mail's editorial board.

Mr. Wall, by contrast, is taking a harder line.

And environmentalists said Tuesday the premise of his argument is wrong: even if Canada stopped importing foreign oil, that oil would still be pulled out of the ground and used elsewhere.

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"It will just be burned somewhere else. There is still increasing oil demand on the planet," said Tim Gray, executive director of Toronto-based Environmental Defence.

"The idea that somehow the tar sands can increase their output and it will still be a wash on a global scale just doesn't make any sense."

With a report from Shawn McCarthycCarthy