OTTAWA -- The federal government will bring in additional measures later this fall to lower Canadian carbon emissions, Environment Minister Catherine McKenna says.

Last week, Prime Minister Justin Trudeau announced he would impose a $10 per tonne carbon tax on provinces and territories that don't put in place their own carbon price – a tax or a cap and trade plan - by 2018. The cost will ramp up by $10 per year until it hits $50 per tonne in 2022.

Trudeau’s announcement, made while McKenna was meeting with her provincial and territorial counterparts in Montreal, led three environment ministers to walk out.

The environment ministers had been in talks for months over how to implement a national carbon price, but some said the announcement's timing was a blow. McKenna says they're still in talks over what else will come later this fall.

"In Montreal this past week, everyone agreed we need to take other measures. Everyone knows what they are," she said in an interview with Evan Solomon, host of CTV's Question Period.

The new measures will include making buildings and houses more energy efficient, McKenna said, pointing to new builds as well as the need to retrofit existing buildings. McKenna also said there need to be measures for vehicles, and that Canada needs to look at adaptation measures.

"There's going to be a range of measures and we're going to be doing it with the provinces and territories. The plan is going to be announced in the fall," she said.

'What is the point?'

Pricing carbon is necessary to send a market signal, McKenna said, but a carbon price alone isn't enough to meet Canada's emission reduction targets.

"If you were to do that, the price would be so high, it wouldn't make any sense," she said.

"We're going to be thoughtful, we're going to be practical."

McKenna says the tax will be revenue-neutral for the federal government because it will provide the money to the provinces to use as they please, whether through tax cuts or additional funding for other programs. Critics argue that isn't revenue neutral, since the provinces could decide to use the money for programs rather than returning it to Canadians through tax cuts.

British Columbia and Alberta already have a carbon tax, while Quebec and Ontario have introduced cap and trade systems. That means more than 80 per cent of Canadians already live with some kind of carbon price. B.C. returns the $30 per tonne carbon tax to people through a tax cut.

Saskatchewan Premier Brad Wall, who opposes the mandatory carbon tax, said if the message is that he can return the money to the sectors most affected by it, then it isn't achieving anything.

"If she's saying that, fine, but then what is the point of this tax?" Wall said in an interview on CTV's Question Period.

Wall says he fears the impact on his province's economy when companies are deciding whether to invest there or in North Dakota, just across the U.S. border.

"If they've got a $50 carbon tax in our province thanks to the Trudeau government, and they don't have one in North Dakota, and they will not, what does that do to North American competitiveness?" Wall said.

McKenna says it would be helpful for each province and territory to work with the federal government to design a system that makes sense for them.

"There's a lot of politics in politics but I'm here to do a job," she said.