A group of economists has come out against the $14-billion gas pipeline project slated for the Saguenay region, saying claims the liquefied natural gas would be among the greenest in the world are insufficient to justify the project.

A total of 40 economists signed an open letter, published in La Presse Tuesday, to state their opposition to the Énergie Saguenay pipeline project .

"Since Canada is having trouble reducing its greenhouse gas emissions, it should stop facilitating projects that will grow emissions," the letter states.

The project would involve the construction of a pipeline across a 782-kilometre stretch of the province — from northern Ontario to Saguenay — and the building of a liquid natural gas (LNG) plant, as well as a marine terminal to ship the liquid natural gas (LNG) to overseas markets.

GNL Québec is the company promoting the project, and Gazoduc inc. is the company developing the new infrastructure. They maintain that transforming the gas to liquid with hydroelectricity would make the project clean — but the economists say this is difficult to back up.

"They would have to provide some certainty as to how the natural gas is going to be used," said Eric Miller, an economist with York University, who is one of the signatories of the letter in La Presse.

"So in the absence of any assurance, then it turns into a bit more of a rhetorical claim about what the possibilities are."

The letter states that although the companies behind the project claim the gas will replace more polluting energy sources like coal, there is no guarantee that it would not replace conventional gas or even renewable electricity.

Claims the project will create 6,000 jobs during construction and 1,100 thereafter also need to be put into perspective, the economists argue.

Jobs promised in the region will be filled almost exclusively by workers from outside the region, or by workers leaving their current job to work on the gas complex, the letter says.

Miller says it's important for economists to weigh in on environmental issues. In June, more than 150 scientists voiced their concerns about the project in their own open letter in Le Devoir and the National Observer.

"It's actually making use of their research and adding our additional economic dimension where we raise a number of questions that we have that have yet to be answered," he said.

Quebec Environment Minister Benoît Charette said Tuesday the project is still subject to two consultations before the province's environmental review board, known as the BAPE, and that the project is not guaranteed to go ahead.

He said GNL Québec and Gazoduc inc. will also have to show the project is economically viable.

In a statement, GNL Québec said it has consulted the population and Indigenous communities, and is working with scientific experts to address environmental concerns.

Project emerges as election issue

Federal party leaders were pressed for their own position on the proposal on the campaign trail Tuesday.

NDP Leader Jagmeet Singh told reporters in Toronto he doesn't support the Énergie Saguenay project because it fails to meet three criteria: it must satisfy environmental assessments and be in line with emission reduction plans, have the support of local and Indigenous communities and create jobs.

"If those criteria aren't satisfied, we should not go ahead," said Singh. "In this case I've said it does not satisfy these criteria, and that's why I don't support the project."

Conservative Leader Andrew Scheer said it's "self-evident" that it's better for the environment to have Canada export its own natural gas to other countries.

He said Canada extracts its natural resources "at the highest environmental standards" and the world should have more access to Canadian energy to avoid using "dirtier coal" and "buying oil and gas from regimes with terrible human rights records."

"I believe projects that can attain those very high standards should be allowed to proceed," he said.

Bloc Québécois Leader Yves-François Blanchet said again Tuesday he would await the BAPE report before supporting or denouncing the project.

Liberal Party Leader Justin Trudeau, for his part, also said he trusts provincial environmental assessment procedures, and he would wait for the results of the environmental assessment.