This article by David Akin originally appeared in the National Post. 

OTTAWA — Federal finance department officials have calculated how much more Canadian households could pay each year as a result of a pending federal carbon tax but neither the department nor Finance Minister Bill Morneau will share those details.

Morneau is being challenged in Parliament by Conservative MP Pierre Poilievre to publish that information while Saskatchewan Premier Brad Wall, who, like Poilievre, is an opponent of a federal carbon tax, has been challenging Prime Minister Justin Trudeau to do the same.

Both men say they believe the Trudeau government should provide Canadians with information about the financial consequences to individual households of the pending carbon tax.

For his part, Poilievre, who served as a minister in Stephen Harper’s notoriously disclosure-averse cabinet, has been using federal access to information laws as well as his prerogative as a member of Parliament to compel the government to disclose the cost of carbon taxes to Canadian households.

In the House of Commons Monday, Poilievre pressed Morneau to table that information.

“The measure of a society is how it treats its most vulnerable. That is why I asked how it is this carbon tax will impact on the poorest Canadians,” Poilievre said during question period. “At first, the government said, ‘No such data exists’. Then it said, ‘It exists; we just don’t want to tell you what it is.’ That is the current position of the government, that it wants to keep secret from Canadians, the most vulnerable Canadians, those with the least, the impact of this heavy new carbon tax on heat, hydro, gas and electricity.”

Trudeau has told provinces that they must, by 2018, put a price on carbon at a level high enough that they can help Canada achieve its international commitments to reduce greenhouse gas emissions. But he has also said on numerous occasions that he expects provinces to use whatever revenue they generate by pricing carbon to be turned back to the citizens of that province to help offset any increase in the prices of goods or services.

One of the documents Poilievre received under federal access-to-information laws is an internal finance department memo written on Oct. 20, 2015, in which the department tries to figure out the financial impact of a federal carbon tax on different kinds of voters.

The memo, titled “Impact of a carbon price on households’ consumption costs across the income distribution” was written by Jean-François Perreault. Perreault was then an assistant deputy minister at Finance Canada. He left the finance department in the spring of 2016 to join Scotiabank as its chief economist.

Much of Perreault’s memo, a copy of which was provided to the National Post by Poilievre’s office, has been heavily redacted by government censors.

But Perreault is crystal clear on this point: Pricing carbon, be it through a carbon tax or a cap-and-trade system, will hit consumers in the pocketbook.

“These higher costs (which) would then cascade through the economy in the form of higher prices, thus leading all firms and consumers to pay more for good and services with higher carbon content.”

In the memo, Perreault prepared a table that laid out several different carbon pricing scenarios and, for each scenario, assessed how it would affect the value of all Canadian economic activity; how much revenue would be produced for governments; and how many fewer megatonnes of greenhouse gas emissions would be genereated in each scenario. All the numbers, though, in that table were blacked out.

Poilievre tried to get the same information through a parliamentary procedure known as an Order Paper Question but the government’s reply was full of what his office described as “talking points” and did not provide the financial information he was seeking.

Wall, the Saskatchewan premier, said in December that Trudeau’s carbon tax could cost the average Canadian family as much as $1,250 a year in higher prices for everything from groceries to gasoline.

He, too, has asked the federal government to release its calculations and estimates of the costs of a federal carbon tax.