EDMONTON -- Andrew Weaver isn't what you'd call an oilsands apologist.
Weaver, who holds the Canada Research Chair in Climate Modelling and Analysis at the University of Victoria, was a lead author with the UN Intergovernmental Panel on Climate Change. He is one of the world's leading authorities on global warming, and one of the fiercest critics of the Harper government's carbon emissions policy -- or lack thereof.
That's what makes Weaver's latest research publication such startling news. On the weekend, Weaver and his doctoral student, Neil Swart, published an analysis in the scientific journal Nature Climate Change, an offshoot of Nature, the world's most prestigious science journal.
In their paper, Swart and Weaver conclude the impact of burning all the economically viable proven reserve of Alberta's oilsands -- all 170 billion barrels -- would be negligible. Burning all the proven reserve between 2012 and 2062, they say, would raise global temperatures by just 0.02 C to 0.05 C.
Burning up all the oil in the areas currently being mined would have even less impact.
"If only the reserve currently under active development were combusted," they write, "the warming would be almost undetectable at our significance level."
Even using up every last estimated drop of estimated oil-in-place, including bitumen that's currently inaccessible or unproven -- even if such a thing were possible -- would raise global temperatures by roughly 0.35 C.
That's a stark contrast to the claims of those such as NASA climate scientist James Hansen, a leading opponent of the Keystone XL pipeline, who described Alberta's oilsands as "the biggest carbon bomb on the planet."
"There's a lot of really strong emotional rhetoric on both sides of the oilsands and climate change debate," says Swart, the paper's lead author. "We're hearing from a lot of people that if the oilsands are used, there will be a climate apocalypse. But part of the picture is that, in and of themselves, the oilsands will not cause climate calamity."
That finding might come as a surprise to some, as it did to Swart himself. He set out to crunch the numbers because he couldn't find any elsewhere.
"I just wanted to know how much warming would there actually be if the oilsands were utilized? Certainly what I can say is that it wasn't what I expected relative to what I had heard previously."
Swart and Weaver say the biggest potential contributors to global warming are non-conventional gas and coal.
The two scientists certainly don't give the oilsands a free pass. They note that their paper doesn't weigh the other environmental consequences of oilsands development, such as their impact on water quality or wildlife habitat.
(They also don't include the so-called well-to-wheel life-cycle carbon emissions of mining, upgrading and refining raw bitumen, in part because those numbers are so difficult to objectively prove. They estimate, though, that including those numbers might raise the total carbon impact 17 per cent.)
Nor do they argue in favour of building pipelines, including Keystone or Gateway.
Indeed, the paper concludes by advising North American policy-makers to avoid "commitments to new infrastructure supporting dependence on fossil fuels."
The real danger of Alberta's oilsands, as Swart sees it, isn't the warming caused by burning our bitumen. It is, more subtly, that the oilsands make it all too easy for North Americans to remain reliant to fossil fuel. With so much oil accessible, so close to home, it's harder to convince people and policy-makers to wean themselves off fossil fuel, period, be it oil, gas or coal.
"It is absolutely essential that we make a rapid transition to renewable energy," Swart says. "If we continue to commit to this fossil-fuel pathway, then the amount of global warming is going to be significant."
Since the provocative paper was published on Sunday, the phones at the University of Victoria have been ringing off the hook with calls from journalists around the world. In the blogosphere, Swart and Weaver's paper has been embraced by some oilsands advocates as validation and endorsement of oilsands production and pooh-poohed by others as old news.
Meanwhile, some climate-change activists have condemned the findings, with some even suggesting that Weaver has been bought off by "Big Oil." Not everyone has bothered to read the paper, which takes the more nuanced view that while the oilsands add little to the world's carbon footprint, they are a significant enabler of fossil-fuel addiction.
Andrew Leach is a professor of energy and environmental economics at the University of Alberta's School of Business. He says the real value of Weaver and Swart's study is that it makes it possible to debate the environmental costs and economic benefits of oilsands development with real data.
"This is what I've been saying for a while," Leach says. "Let's at least have a sane discussion with the right numbers in front of us."
Leach is quite right. Swart and Weaver's findings certainly shouldn't give Albertans a feeling of smug licence to keep developing oilsands or building pipelines pell-mell. But this objective data from two respected climate-change scientists provides vital context to putting the oilsands' total impact on world climate change in perspective.
For his part, Swart says no matter how others might misinterpret or torque the conclusion in the paper, he and Weaver have a duty as scientists to report the truth, regardless of politics.
"Our responsibility as scientists is to report the facts, so that society and decision-makers can make informed decisions based on factual data and not emotional rhetoric," Swart says. "If it is the case that some of this information is misused, that's unfortunate, but we can't help that. Good facts have been missing from this debate in the past. It's our job to provide them."
Paula Simons is a columnist
for the Edmonton Journal.