TORONTO — Facing a growing carbon-tax revolt from the provinces, federal Environment Minister Catherine McKenna lashed out at her Ontario counterpart over the weekend.

In a series of tweets at provincial minister Rod Phillips, McKenna appeared incredulous at his approach to climate change.

[READ MORE: NDP urges Liberals to meet new UN emissions targets]

In response to Premier Doug Ford’s anti-carbon-tax rally in Alberta, Phillips tweeted that he is “proud of the leaders from across the country, who are uniting against regressive taxes.”

She had a sarcastic tweet in response.

“Unbelievable. While scientists from around the world call for urgent climate action, the Ontario Minister of the Environment is *proud* to be fighting climate action,” she said. “By killing their climate plan, Ontario is increasing pollution equal to over 30 new coal-fired plants. Proud.”

Last week, Manitoba joined a growing list of provinces bailing on Ottawa’s climate-change strategy and daring the federal government to impose a federal carbon tax without buy-in from provincial governments.

Then on Thursday and Friday, Ford took a swing through the Prairies to rally opposition to a carbon tax. In Alberta, Ford joined United Conservative Party Leader Jason Kenney at a “scrap the carbon tax” rally. Kenney is hoping to unseat NDP Premier Rachel Notley, who has already pulled Alberta out of Ottawa’s carbon-pricing plans.

In Saskatchewan, Ford met with Premier Scott Moe. Both leaders are in the middle of legal challenges to Ottawa’s plan to impose a carbon tax.

[READ MORE: Raucous crowd hears Ford, Kenney rail against carbon tax]

In another tweet, McKenna mocked the rookie Ontario government’s court case and its $30-million price tag, and questioned Phillips’ priorities.

Reminder that $30 million of your Ontario taxpayer money will be spent to fight climate action and make pollution free. Meanwhile money to support climate action by Ontario cities, schools, hospitals, biz, families that would save money & do right by the planet was cut. Proud? https://t.co/Nr4VvXsSME — Catherine McKenna 🇨🇦 (@cathmckenna) October 8, 2018

Phillips replied to McKenna with his own jabs at what he has called her government’s “dogmatic” approach to fighting climate change. “What’s *unbelievable* is that 6 provinces (and counting) have rejected your ineffective carbon tax plan. Yet, you are still unwilling to work collaboratively on solutions to reduce GHGs that don’t tax the people,” he wrote.

The ministers — both of whom write their own tweets — have had a frosty relationship since the start. Their first meeting at Queen’s Park ended with competing media availabilities in different parts of the city.

On Twitter, at least one economist came to McKenna’s defence, accusing Phillips of “making stuff up” when he called the carbon tax a “regressive” tax.

“The Alberta carbon levy and rebate combined is strongly progressive. The B.C. carbon tax and associated tax reductions and rebates is strongly progressive. The removal of these programs would be regressive,” wrote Andrew Leach, an associate professor at the Alberta School of Business.

Phillips also maintained that “Ontario is on track to meet Paris 2020” targets, but the province’s environment commissioner says the opposite is true.

Commissioner Dianne Saxe tabled her report on greenhouse-gas emissions in Ontario last month. In it, she said the new government’s decision to leave the cap-and-trade market with Quebec and California and scrap the climate-change plan will take Ontario further away from its emissions targets.

“I think our emissions are going to go up. I think we’re going to be getting further and further from where we need to be, just as climate change begins to really punish the people of Ontario,” Saxe said in September.

In Toronto on Tuesday, the deputy leader of the federal Conservative party said the partisan jabs exchanged between the two ministers won’t take away from them working on overlapping files.

“It is the responsibility of the ministers to continually have a good working relationship with their counterparts. Both those ministers have that onus on them,” Lisa Raitt said.

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