Just 32 days before Canada's federal election, passions ran high at the Globe and Mail debate as Thomas Mulcair ripped into Stephen Harper for his aggressive promotion of pipeline-building deals and tearing up the Kyoto protocol in 2011.

“Shamefully, Stephen Harper made Canada the only country in the world to withdraw from the Kyoto protocol," said the NDP leader, who said that Canada had to honour its international obligations. "When I talk about avoiding leaving a massive debt on the backs of future generations, this is exactly what we’re talking about.”

Both Mulcair and Liberal leader Justin Trudeau criticized the prime minister for weakening environmental regulations at at time of increasing pressure to create policies to mitigate climate change.

Liberals supporting provinces on climate policy

While Mulcair advocated a national plan for slashing emissions and investing in both green energy and infrastructure including public transit, Trudeau preferred to focus on supporting the provinces, who are already forging ahead with carbon taxing, cap and trade, and renewable energy growth.

Statistics seem to back him up: in 2014 alone, Canada's provincial governments invested $10.9 billion in renewable energy development, creating nearly 27,000 jobs, and adding 3.63 gigawatts in clean power output.

The Liberal leader felt that such a decentralized approach would be more effective than Mulcair’s top-down plan for slashing greenhouse gas emissions, but later promised $20 billion in green infrastructure from a new Grit government.

“For 10 years under Mr. Harper, with no leadership on the environment, provinces have moved forward and 86 per cent of our economy – our four biggest provinces – have actually committed to putting a price on carbon and they’ve done it in different ways which makes Mr. Mulcair’s approach so unrealistic,” said Trudeau.

Harper, for his part, said that emissions reduction was best handled through a regulatory regime “sector to sector,” to learn the costs and effects of new laws before implementing them.

“Carbon taxes are about raising revenue for the government,” said Harper.

Harper said that his government was the first in history to both cut emissions and grow Canada’s economy, adding that the energy sector was a key economic driver that needed a government on its side as world oil prices collapse.

“We want to see the sector grow and develop,” said Harper.

Harper's policies detrimental to energy industry?

Mulcair shot back, lambasting Harper’s energy policy as the main reason why companies have been unable to to build “one kilometre of pipeline to tidewater." He argued that Harper's gutting of environmental laws have left Canada without any credible environmental assessment process, making it impossible for the public to back approved projects.

“He thought he was helping the energy companies by destroying that legislation — he’s actually made their lives tougher,” said Mulcair.

Tempers flared soon after, when Harper blasted his NDP rival for being “the only leader in Canadian history” to go to America and argue “against Canadian jobs and against Canadian development projects,” referring to the controversial Keystone XL proposal, which would carry Alberta's bitumen to refineries in the mid-west.

Mulcair came back swinging, saying that Keystone XL would end up exporting 40,000 jobs to the United States, and that he wanted to create those 40,000 jobs in Canada.

“Mr. Harper talks a good game on international trade deals. He’s done everything in his power to stop the authorities that exist under the North American Free Trade Agreement from even measuring the pollution going into the environment in Canada," said Mulcair. "That’s his track record. We’ll enforce overarching sustainable development legislation, we’ll apply it fairly and equally to everyone, and Canadians will know that we’re going to stop leaving this massive ecological debt on the backs of future generations."

Both Trudeau and Mulcair, in between bouts of sparring with each other, accused Harper of treating the environment and economy as separate and opposed to each other, when really they went hand-in-hand.

“Mr. Harper continues to pretend that there is a choice between environment and economy. He chooses to say that you cannot build a strong economy if you’re protecting the environment — and that has been his failure,” said Trudeau. “He hasn’t gotten pipelines built. He has made the oil sands an international pariah.”

While both Trudeau and Mulcair handily denounced Harper's environmental record, neither leader committed to a concrete emissions reduction target just two months before COP 21.

Green Party leader Elizabeth May, who tweeted rebuttals during the debate due to her exclusion from the Globe event, argued that none of the candidates on stage talked about the urgency of climate change. She said in a video message:

"This debate touched on climate, but never talked about the urgency. Well, it is urgent. The deadline for the new treaty is December, and we have to be ready... we have to reduce greenhouse gases dramatically by investing in our municipalities, by reducing waste, improving energy productivity and jumping on board the clean energy revolution."

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