Calgary Mayor Naheed Nenshi continued his pipeline diplomacy Thursday, bringing his message of Canada-wide cooperation to an eastern audience that has been skeptical about the Energy East proposal.

"Rather than an inflammatory conversation pitting energy advocates against environmental advocates, we need to work together, as a community, as a nation, to get this right," Nenshi told a gathering of big-city mayors in the nation's capital.

"We have to get Canadian energy to tidewater. We have to do it. There is no choice for the prosperity of this nation but to make that happen."

Notably absent from the gathering was Montreal Mayor Denis Coderre, who has been the most outspoken of municipal leaders to oppose the Energy East project, which would see an existing natural gas pipeline converted and extended to carry oil from Alberta to port in New Brunswick.

Nenshi made the case to the eastern-dominated crowd that it's in everyone's best interest to see Alberta's largely land-locked resources find a way to sea for export to international markets.

It was sterner in tone but similar to the message the Calgary mayor tried to deliver to a national audience through humour with a recent appearance on This Hour Has 22 Minutes, where he "demonstrated" to host Mark Critch via a prop "pipeline" that when you put Alberta bitumen in one end, you get money out the other.

The Calgary mayor said the recent rhetoric from some of his municipal counterparts has turned into a "sideshow" that ultimately isn't all that relevant, since it's not up to municipalities to approve or reject such projects or impose conditions on them.

He also tried to walk the line between environmentalism and energy-industry boosterism, saying reasonable people can disagree on some issues while still finding common ground on others.

"To have a thoughtful conversation – a thoughtful conversation – on the importance of our energy industry is not to be a cheerleader for climate change," Nenshi said.

"Developing our resources in a responsible and sustainable manner is not an attack on the energy industry," he added. "It's about government and industry working together to respond to opportunity and to respond to changing expectations from people around the world as it relates to the environment."

'Abide by the science'

Overall, Nenshi said the federal government's newly revamped pipeline review process should be completed before rushing to final judgments on Energy East or other projects.

"Let's use a rigorous, science-based process. Let's strip emotion out of it and determine whether these things are in the best interest of the nation," Nenshi said. "I happen to believe they are. But let's let the National Energy Board do its work and let's pledge to abide by the science here."

Ottawa Mayor Jim Watson echoed that.

"It's important for us to allow the process that we've all agreed to, to follow through," he told reporters

"Before anyone jumps to conclusions and jumps on one bandwagon or the other, let the National Energy Board do its work."

Others, like Quebec City Mayor Régis Labeaume, were less enthusiastic.

Quebec City Mayor Régis Labeaume

Quebec City Mayor Régis Labeaume says TransCanada has been "arrogant" in its dealings with communities like his. (CBC)

While Labeaume said he believes pipelines are a safer alternative to transporting oil by rail, he reiterated his earlier criticism of TransCanada, the company behind Energy East, over the way it has interacted with communities in Eastern Canada.

"I don't know if they're arrogant or incompetent but they don't know how to work," Labeaume told reporters.

"It's kind of stupid. I think they've got to change their way to work. They have to, because if they don't change their way to work, they're in deep trouble with us and with everybody."

Louis Bergeron, vice-president for TransCanada Corp.'s Energy East project in Quebec and New Brunswick, acknowledged his company has not been doing a good job of selling the project to communities in Quebec.

"There were disconnects and I think that's one of the problems that we had," he said.

"We weren't nimble enough, we weren't capable of reaching the communities and coming up with some concrete solutions that people are expecting to get from us."