OTTAWA -- Criticism about the government's carbon tax plan from federal and provincial Conservative leaders is, in part, a "smokescreen" for not having presented climate change plans of their own, says Environment Minister Catherine McKenna.

In an interview airing Sunday on CTV’s Question Period, McKenna defended the federal carbon pricing "backstop" and rebate plan announced on Wednesday. It will be applied in New Brunswick, Ontario, Manitoba, and Saskatchewan because the leaders in those provinces have negated to install a climate change plan that meets federal expectations for pricing pollution.

The first "Climate Action Incentive" payments -- between $128 and $305 for a single adult in 2019 -- will land in voters' bank accounts ahead of the next election.

This week, Conservative Leader Andrew Scheer called the new rebate plan an "election gimmick” and re-stated his pledge to scrap the plan if his party forms government in 2019.

Speaking to the pushback and criticism the federal Liberals are receiving from these top Conservatives, McKenna classified their opposition partly as "a smokescreen for not having a plan."

Among what the federal Conservatives have taken issue with: the Liberals’ decision to give industry more room before companies start paying by relaxing their proposed carbon tax limits on large emitters, and focusing on a carbon tax as the best way to cut emissions.

On CTV’s Question Period, Saskatchewan Premier Scott Moe said his resistance to Ottawa's plan comes in part because his province is already contributing to Canada's aims to clean up the environment -- without a price on carbon.

Moe said the provinces know best what works in their region to reduce emissions. Though, the federal government did encourage provinces to come up with plans of their own and Saskatchewan’s didn’t go far enough.

"The problem with what Conservatives are doing is that they aren't saying what their plan is, they keep on trying to find some excuse for why they think our plan isn’t right," McKenna said.

On a recent appearance on CTV’s Question Period, Scheer couldn't say definitively if his still-being-drafted environment plan will meet the United Nations targets he's previously committed to, but that it will have a "meaningful" impact on global emissions.

"The question for everyone is, 'What are you going to do?' Stop poking holes and saying things that aren't true about our plan, and show Canadians what you would do," McKenna said, noting that "for too long politicians have done nothing."

Though, when asked to confirm her plan will meet the UN Paris Agreement pledge to keep global warming below 2 degrees Celsius, McKenna couldn't say. Instead she pointed to the various environmental initiatives she’s overseeing, saying that there is more to their plan than a price on pollution.

It’s not the first time there's been doubt over whether the Liberal plan will do what’s needed to reach levels that will help stop devastating impacts of climate change. A recent United Nations Intergovernmental Panel on Climate Change report said that worldwide, countries need to make much larger cuts to emissions, something McKenna has told The Canadian Press there are no immediate plans to do.

'Atmosphere is boss': May

While the issue is already proving to be a hot button political topic, Green Party Leader Elizabeth May issued a sobering reminder to her colleagues: "The atmosphere isn't interested in negotiating with Andrew Scheer or Justin Trudeau; the atmosphere is boss."

"If we don’t reduce our emissions far more than what Catherine McKenna and Justin Trudeau are currently committed to doing, which is the old target that Harper left behind, then we do have the burden of moral responsibility of abandoning our children to an unlivable world," May said on CTV's Question Period.

She poured cold water on the idea of a carbon tax being the defining political issue leading in to the 2019 federal election, doubting that Canadians want their leaders to continue debating the issue rather than take hard steps.

"I think they'll react in horror at politicians that put short-term political advantage over an issue as existential for human survival as this one is," May said.

Watch Question Period Sunday mornings on CTV, CTV News Channel,, CTV News GO, and on CTV News’ Facebook page at 11 a.m. ET, 10 a.m. CT, 9 a.m. MT and 8 a.m. PT