So what does this mean for Canada? It is first and foremost the definitive nail in the coffin for Stephen Harper’s disastrously antagonistic legacy of advocacy for pipeline projects.

Environmentalists should consider a fruit basket, or perhaps an electric car for the former prime minister to use on his ride off into the sunset. A PM better able to pay lip service to the concerns of climate scientists, while nevertheless pushing for tar sands development, would likely already have a pipeline or two built.

With friends like Stephen Harper, Big Oil may now be asking, who needs enemies?

The pipeline conundrum

Oil companies operating in the Canadian tar sands have pushed relentlessly for the expansion of the Mordor-like area of Alberta, with plans to double output to over 4 million barrels per day by 2024. Following a 48 per cent drop in crude prices last year, and fierce resistance to pipelines, many of those projects are now being shelved and reevaluated.

So why are pipelines so important?

One of the arguments we often hear is that if we don’t build pipelines the oil will just be transported anyway by rail, with all the attendant safety risks. In reality, this is a convenient fiction propagated by the oil industry to blunt the arguments of those opposed to pipelines.

It’s true that the traffic of oil by rail increased in Canada by 28,000 per cent in the four years between 2009 and 2013, but even that is a drop in the bucket.

Despite this astronomical increase in the volume of crude shipped by rail, through the first three quarters of 2014 oil-by-rail accounted for just a little over 150,000 barrels per day.

That sounds like a lot, and it is, but it pales in comparison to the capacity of any of the major proposed pipelines. Keystone XL? 830,000 barrels per day. Kinder Morgan? 890,000 barrels per day. Northern Gateway? 525,000 barrels per day. And the largest of them all, Energy East, will ship 1.1 million barrels per day if constructed.

For the tar sands to expand as planned, and increase output to over 4 million barrels per day, oil companies need infrastructure to get that oil to market. Trains currently carry 150,000 barrels per day, and the capacity of that infrastructure has been stretched to the breaking point. If only Kinder Morgan and Energy East were to be built, they would carry almost 2 million barrels per day. Clearly, the one cannot replace the other.

Simply put, if trains are the plan for transport, then the tar sands cannot expand on the scale envisioned.

Why not expand the tar sands?

The scientific consensus is clear: if we want to hold global warming to 2 degrees, which scientists agree is essential to avoid catastrophic changes to our climate, then we need to leave the majority of the world’s known fossil fuel reserves in the ground.

But here’s the problem: doing that means writing off around $20 trillion worth of assets, currently held by oil companies and countries. Those assets are counted like gold in a bank vault when it comes to the stock price of oil companies or the credit rating of a country. Wiping them off the books would damage the economy, but failing to do so will damage the planet, and could even render parts of it uninhabitable.

It’s not hard to understand why companies facing the prospect of billions in stranded assets would do anything to fight effective action on climate. That’s what New York’s attorney general thinks Exxon Mobil did, and they’ve launched an investigation into the oil company for lying about climate.

The New York Times reports that the investigation will focus on the allegation that “Exxon Mobil funded outside groups that sought to undermine climate science, even as its in-house scientists were outlining the potential consequences — and uncertainties — to company executives.”

Easy as it is to understand why Exxon would prioritize its profits over the future of the human race, it’s somewhat harder to understand why governments have eagerly gone along for the ride.

But the stakes are even higher in Canada. The oil extracted from the tar sands is heavy, hence the tar part, and as such it produces more greenhouse gas emissions than other oil reserves. So while everyone recognizes that we’ll need to keep using oil as we transition onto 100 per cent renewable energy sources by 2050, all oil is not created equal.

A study published in the prestigious scientific journal Nature found that over 85 per cent of the tar sands will need to remain buried if we are to avoid the type of rapid warming that could cook our planet.

The tar sands is not only one of the largest fossil fuel reserves left on earth, it is also one of the dirtiest when it comes to carbon emissions. The struggle to halt climate change is a global one, but if the tar sands continue to expand that fight will be over before it begins.

An audacious plan

Coming out of the disastrous Copenhagen climate conference in 2009, activists in North America realized that governments simply lacked the political will to act. The tar sands represented one of a few key battlegrounds that would decide, in very real terms, the future of the planet, but the Canadian government was openly contemptuous of the science showing that rapid expansion could not proceed.

Recognizing this expansion would require increased transportation capacity, activists zeroed in on pipelines. There are only three directions a pipeline can go from Alberta: south, through the U.S., west, through British Columbia, or east through Quebec and the Maritimes.

So they came up with a plan, a plan so implausible it is to laugh. Or it might have been, before it started to work.

Block pipelines in all three directions and you landlock the tar sands, killing expansion plans and forcing oil companies and governments to leave much of the oil in situ. Call it climate regulation by grassroots action.

Two down, two to go

So where do the activists who set out to blockade the tar sands stand after six years? Keystone XL is dead, and if a Democrat wins the White House again in 2016 it and other projects like it will stay dead.

Canada’s new Liberal government made a campaign promise to impose a moratorium on tanker traffic on B.C.’s northwest coast, and while they may renege in the future, that means projects like Northern Gateway are unlikely to proceed any time soon.

That leaves two pipelines still standing in this epic battle between grassroots activists determined to landlock the tar sands, and the oil companies and governments determined to get their oil to market. Kinder Morgan to the west, and Energy East.

Energy East

Canadians have been enjoying a honeymoon period of sorts with new leader Justin Trudeau, and in many ways that goodwill is warranted. He’s already restored the long-form census, unmuzzled government scientists and appointed not one but two ministers of science to his cabinet. A cabinet which is composed of as many women as men, a welcome development in a country where scarcely 26 per cent of elected MPs are women.

In many ways the exuberant relief which has followed the October 19 election is more about the prime minister we no longer have, rather than the man who now occupies the office. A friend described it as the immense sense of relief one would experience if you had been hit over the head with a hammer every day for ten years, and one day that dunning abruptly stopped.

But whatever he may be on other files, Justin Trudeau is no saviour on climate.

Throughout the campaign he made the counter-factual argument that you can take meaningful action to address climate change while also expanding the tar sands exponentially.

In 2014 Trudeau said that “opposition to the Keystone XL pipeline in the United States and elsewhere is not scientific,” and in a short statement responding to today’s White House announcement he explained that his government was “disappointed by the decision.”

In the election’s final days a scandal erupted when it was revealed that Dan Gagnier, a senior advisor to Trudeau and co-chair of the Liberal campaign, was simultaneously on the payroll of TransCanada, the company behind the Energy East pipeline, and prepared a memo for senior executives there on how to lobby a new Canadian government to approve the project.

Gagnier resigned, but the scandal raises serious questions about how Trudeau will deal with the largest pipeline ever proposed in North America.

With westbound pipelines on the back-burner due to ferocious opposition from Indigenous communities and grassroots campaigns, all eyes will shift to Energy East. It’s a pipeline Trudeau supported during the campaign, and new Foreign Affairs Minister Stephane Dion reiterated that support today, stating that the Liberal government supports Energy East, but wants to increase confidence in the environmental assessment process. But if Trudeau wants to see it built he’ll have to go through Quebec, where over two-thirds oppose the project.

That opposition will only increase as the public learns more about the science on climate, and the urgency of halting tar sands expansion.

Beyond Paris

Trudeau will arrive in Paris for next month’s COP21 climate conference with a large retinue of provincial premiers and opposition leaders, but no plan to reduce carbon emissions.

The truth is that there’s only one plan that makes sense, according to the scientific evidence: keeping 85% of the tar sands in the soil. That cannot happen if Energy East is approved. Ditto for Kinder Morgan.

The good news is that where Stephen Harper relied on a political base that didn’t give a fig newton about climate change, the same cannot be said for Trudeau. Many of the voters who gave Trudeau their trust in the last election fall in the 50 per cent of Canadians who oppose Energy East.

If nothing else, Canada now has a prime minister who is susceptible to public pressure. It’s time to turn that pressure up. Otherwise the short term economic interests of oil companies are likely to trump the long-term interests of the human race.