Construction on the Manitoba segment of the biggest project in Enbridge's history is slated to begin in a couple of months, but you've likely never heard of it.

Line 3, as it is known, is a new crude-oil pipeline — with a predicted price tag of $8.2 billion — set to be built along the route of a smaller, existing pipeline operated by the Calgary-based oil and gas giant.

Construction has already begun west of Manitoba on the line, which will cut a path through the Prairies, from the Alberta oilsands en route to the shores of Lake Superior in northwestern Wisconsin.

The new pipeline has been billed as a replacement for the existing, aging infrastructure, but in reality is a massive expansion that will nearly double the capacity from what Enbridge says is a low of 390,000 barrels of crude oil per day to 760,000 barrels a day.

A map showing the route of the Line 3 pipeline replacement from Hardisty, Alta., to Superior, Wis. The expansion will nearly double the amount of oil shipped daily via the line. (The Canadian Press)

There has never been a more important time to think critically about the kinds of energy infrastructure we invest in. So why hasn't there been more discussion about one of the largest oil infrastructure investments in North American history?

For starters, Enbridge promotes Line 3 as a routine replacement operation. This narrative overlooks the fact that the old pipe will be decommissioned, but not removed — and the new pipe is a significant expansion that deviates from the original route in the U.S.

The Trudeau government has also played a role in downplaying Line 3 by bundling its authorization with the much higher-profile approval of the Kinder Morgan Trans Mountain pipeline, and the rejection of Enbridge's Northern Gateway line.

Unlike the Kinder Morgan line, which has been met with significant resistance in its urban terminus of Burnaby, B.C., Line 3 does not pass through any large Canadian cities where a base of opposition might have taken shape.

Those who want to see Line 3 built have been successful in keeping it out of the public eye. So why should we be talking about it?

Line 3 is a long-term commitment to a reliance on fossil fuels that comes with many risks and few rewards. Not only will we be paying for the environmental damages that this crude oil will invariably cause through spills and contributions to climate change, but we are literally paying for it now with our tax dollars.

With $3.6 billion in governmental subsidies sunk into the oil and gas industry in the 2013-14 fiscal year alone, for example, Line 3 is our investment as Canadian taxpayers.

It is our responsibility as citizens to take a closer look at this investment and consider what this project means for us.

A good investment?

We are living in a world that is moving away from fossil fuels, though this is not always apparent in our everyday lives. The Canadian National Energy Board predicts that Canadian fossil fuel use will reach a peak in 2019, before declining rapidly over the coming decades.

And this is a global trend. A recent report by Policy Horizons Canada cautions against new investments in oil infrastructure like Line 3. The logic is simple: oilsands oil is some of the most expensive to produce and will be the first to get priced out of the market as global competition increases.

Not only is Line 3 a short-sighted investment when we look at the shift in global energy economies, it also does little to contribute to local economies in the long term.

Beyond temporary construction jobs (construction on the line is expected to be done by July of 2019), Enbridge does not cite any permanent jobs for Line 3 in our province.

If economic stimulus is the goal of energy development, we are much better off looking to alternative energy sources where the job creation rate outpaces that of the oilsands.

Enbridge's Line 5 pipeline is seen in this June 2017 file photo near St. Ignace, Mich. As demand for renewable energy grows, Canadians should be thinking seriously about moving beyond oil, say Nick Smith and Laura Cameron. (Dale G Young/The Detroit News via AP)

We are already seeing the demand for renewable energies grow as costs of production and storage fall. At some point we'll have to think seriously as a society about moving beyond oil, and in this respect, Line 3 represents a critical juncture.

With the recent cancellation of other pipeline projects like Enbridge's Northern Gateway and TransCanada's Energy East, and the fate of Kinder Morgan's Trans Mountain line up in the air, we have an opportunity to break with the trajectory of business as usual and opt for more sustainable development.

It isn't a question of pipelines versus trains, but a choice between a short-sighted investment in a dated energy source and a commitment to more viable alternatives for the future. As the world shifts to new energy sources like wind and solar, will we choose to follow suit, or remain tied to a dying energy source for decades to come?

Risk of spills

While the economic rewards of Line 3 for everyday Canadians are meagre, the environmental risks are great.

As with all crude oil pipelines, there is always a risk of a spill. Just three months ago, almost 800,000 litres of oil spilled from the Keystone pipeline in South Dakota, a pipeline less than a decade old.

It has since been revealed that the pipeline spills significantly more oil and more often than predicted in risk assessments.

The pipeline has not received construction permits in Manitoba … and now is the moment to express our concerns about the project to our local and provincial governments. - Laura Cameron and Nick Smith

​Enbridge's spill record is far from the clean slate the company tries to pass off in its promotional videos.

The company's own data details over 800 spills between 1999 and 2010, releasing 25.5 million litres of crude oil into the ground.

One of these spills was among the largest inland oil spills in U.S. history. In 2010, 4.5 million litres of oil spilled into the Kalamazoo River in Michigan. Enbridge ignored the alarms for more than 17 hours before reporting the rupture.

Closer to home, Enbridge was responsible for a leak which spewed 1,500 litres of crude oil into a creek near Virden, Man., in 2010. The rupture wasn't discovered until local residents came upon the spill by discovering oil on top of Boghill Creek, which feeds into the Assiniboine River.

Enbridge's spill and response record make it clear that they're more than happy to forgo environmental stewardship and community accountability in order to make money for their shareholders.

Pipeline to the sky

Not only does new pipeline development pose local risks to our lands and waters through potential spills, it also threatens the integrity of our communities and ecosystems locally and others around the world through climate change.

The crude oil that would be transported in Line 3 is some of the most energy-intensive oil to produce in the North America. In fact, there is 2.2 times more carbon pollution emitted per barrel in the extraction and processing of oilsands crude oil than the average North American crude, according to the Pembina Institute.

The Line 3 expansion has not received construction permits in Manitoba or regulatory permits in Minnesota, which leaves a narrow window to express opposition to the Enbridge project, Cameron and Smith say. (Mark Blinch/Reuters)

To commit to extraction and export of 760,000 barrels of oil — enough to fill 47 Olympic swimming pools! — per day for the next five decades does not align with the actions we know we must take now in order to mitigate the impacts of climate change.

Nor does it align with what world governments have committed to do to curb greenhouse gas emissions and transition to a more sustainable energy economy.

Narrow window for opposition

Line 3 will be in the public eye soon enough. With construction slated to start in Manitoba when the ground thaws this spring, it will be increasingly difficult for us to keep our heads turned.

The risks that Line 3 brings — economic, social and environmental — far outweigh any potential rewards. Those on the front lines of oil and gas development shoulder its heaviest burdens, but we all have a stake in the future of our energy sources and ecosystems.

We have a critical, narrow window of opportunity to raise our voices in opposition to this project.

The pipeline has not received construction permits in Manitoba or regulatory permits in Minnesota, and now is the moment to express our concerns about the project to our local and provincial governments, whose responsibility it is to protect our interests.

Canada is at a significant junction in history, faced with the challenges and opportunities of a shifting energy landscape. We must take part in reshaping our energy systems for decades and generations to come.

This column is part of CBC's Opinion section. For more information about this section, please read this editor's blog and our FAQ.