Over the past year or so, opposition to new tar-sands projects has been steadily growing.
The Line 9 hearing comes as two other potential routes for tar-sands oil face problems.
As the plane gained altitude, I could see the vast black pits of the tar-sands mines that surround Fort McMurray.
While there are legitimate environmental worries, replacing gas exports with tar-sands oil is vital for economic growth, argues Matthew Akman, an analyst at Scotiabank.
It is estimated that by 2012 tar-sands operations will consume two billion cubic feet of natural gas a day, or enough to heat all the homes in Canada.
Even more surprising was the decision in February of the federal and Alberta governments to charge Syncrude, a large tar-sands processor, with offences under environmental and bird-protection laws for the deaths of 500 ducks in one of the company's tailing ponds last April.
All the applications opposed by Fort McMurray officials were ultimately approved, and just a few months ago an American company, Hyperion Resources, announced plans to build the first new oil refinery in this country in thirty years, to handle increasing volumes of tar-sands crude.
Crude oil, or its substitutes, will be produced for decades, but at an increasingly expensive tariff, both in terms of cost and energy, as it is sourced in the form of a heavy, sour (high-sulphur) material, or in synthetic form from tar-sands, shale and coal.
For their calculations, the two assumed that where there was a gap between demand and conventional supply it would be filled with synthetic fuels, first with tar-sands oil and later with oil from coal and shale. (According to high-end estimates, coal and oil shale could together yield some ten trillion barrels of unconventional crude.) They then calculated what the impact would be on global carbon-dioxide levels.
Also looming is a decision whether to grant a permit to the Keystone XL oil pipeline, which would transport carbon-laden tar sands oil from Canada to Texas.
For every barrel of synthetic crude that Suncor eventually produces, forty-five hundred pounds of tar sands have to be dug up and separated.
Unconventional sources of oil and gas that are set for further exploitation include Canada's tar sands, shale and coal-bed methane deposits around the world.
Writers Lisa Song, Elizabeth McGowan and David Hasemyer were recognized for a project that began with an investigation into a million-gallon spill of Canadian tar sands oil into the Kalamazoo River in Michigan in 2010.
Suncor expects to continue to pull tar sands out of it for the next twenty-five years.
Earlier this month, the Alberta government brought out a 20-year plan for the greening of the tar sands, which, while light on details, showed more than the usual resolve.
In the Canadian press briefing I went to Mr Kent twice described the tar sands industry as "responsible and sustainable" - a phrase that garnered a fair amount of comment when I tweeted it.
And Canada is still fighting for an exemption from a rule inserted into the 2007 Energy Independence and Security Act that bars the American government from buying fuels whose production causes more greenhouse-gas emissions than conventional petroleum sources, as producing oil from tar sands does.
They will soon bioengineer bacteria to melt oil out of tar sands, turn grass into diesel fuel and scavenge natural resources of every kind out of low-grade, thinly dispersed deposits.
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