A re-elected Liberal government would halve the corporate tax rate for companies that develop or manufacture products with zero emissions — part of the party's plan to move to net-zero emissions by 2050, Liberal Leader Justin Trudeau announced today.

Taxes for small clean technology businesses would be reduced to 4.5 per cent from the current nine per cent under the Liberal plan, while larger companies would pay 7.5 per cent in taxes instead of the current 15 per cent.

Eligible sectors could include manufacturing related to renewable energy, production of renewable fuels, zero emission vehicles and batteries for them, carbon capture and removal technology and electric vehicle charging systems.

It's part of the Liberal promise to push Canada to net-zero emissions by 2050, joining the European Union and countries making the same climate pledge at the United Nations in New York City this week.

"It's an ambitious target, but it's doable," said Trudeau at a campaign event in Burnaby, B.C., the home riding of NDP Leader Jagmeet Singh.

The Liberal Party's plan is to set legally-binding, five-year milestones to reach net-zero emissions in 30 years. The party says the net-zero plan would be based on the advice of scientists, economists and other experts, as well as consultations with Canadians. To date, there have been few details on how those targets will be met, but Trudeau said other announcements will roll out through the week.

Net-zero means some sectors could still emit carbon pollution, but those emissions would be offset by other actions such as planting trees.

The Liberal plan also promises to exceed Canada's 2030 emissions goal.

Liberal Leader Justin Trudeau says Canada reached the three-quarter mark of the 2030 emissions targets in the four years his government was in power. While answering reporters' questions in B.C. on Tuesday, Trudeau insisted that within 11 years, the country will meet and surpass the 2030 targets. 1:02

Trudeau is also announcing a Liberal government would ensure all federal buildings run on clean electricity by 2022, and that the government would strengthen green procurement policies and leverage bulk purchasing power to drive clean technology.

According to the Liberal Party, the clean tech tax measure would cost about $15 million in 2020-21 and rise to about $67 million by 2023-24. The other measures Trudeau announced would be paid for by current departmental resources, the party said.

The Liberal Party said costing details would be released over the course of the campaign. The party has not released a costing analysis carried out by the Parliamentary Budget Officer, as the Conservatives and NDP have been doing with their announcements.

Trudeau said climate change is the great global challenge of the age and tried to frame the choice Canadian voters have to make in the upcoming election as one between ambition and complacency.

"Do you want to be represented by a team that has a serious, ambitious plan that is committed to do more, or do you want a team of climate deniers with no long-term vision for Canada's environmental and economic future?" he said.

Earlier today, Ottawa Centre Liberal candidate Catherine McKenna, who has been serving as federal environment minister, said Canadians have a stark choice to make on climate policy in this election.

"Conservative politicians want to stop this progress. They want to follow (Ontario Premier) Doug Ford's example, where it's free to pollute, where we cancel programs that are helping businesses, schools, hospitals, people save money and do right by the environment," she said during a campaign event at a local Ottawa company that transitions homes and businesses to solar power.

"That is exactly what [Conservative Leader] Andrew Scheer would do, too."

'Moral responsibility' to act

Pressed by reporters on how the Liberals would achieve the ambitious targets, McKenna was light on specifics. She would not say if pursuing a net-zero target would require an increase in the carbon tax, or what penalties could be imposed for not meeting legislated emissions targets.

McKenna said the path forward would be charted by an expert panel, adding climate change represents both a moral responsibility and an economic opportunity for Canada.

Liberal candidate Catherine McKenna, who served as Justin Trudeau's environment minister, says her party would help energy workers transition to a net-zero emissions economy by the year 2050, if re-elected. 1:35

"We may not know exactly how to get there, but that's the same of all the countries that have committed to this and the businesses," she said.

"But we will figure this out, and the way we will do this is by having a serious climate plan with credible and pragmatic action, by listening to the experts and, most of all, listening to young people in the streets who are saying, 'Are you going to act for our future?'"

Millions of young people have taken to the streets in about 150 countries around the world demanding that world leaders adopt urgent measures to avert an environmental catastrophe.

The worldwide action was inspired by 16-year-old Swedish activist Greta Thunberg, who castigated national leaders at the United Nations on Monday for their failure to combat climate change.

The climate change plan would include bringing in something called a "Just Transition Act" to give workers in affected sectors access to training, support and new opportunities to adapt to the transforming economy.

In August, Green Party Leader Elizabeth May offered a similar proposal to transition oil and gas sector workers to green energy jobs.

Carbon tax battle

Key to the Liberal climate change action plan is the carbon tax, which set a minimum carbon price of $20 per tonne this year, increasing $10 a year to $50 by 2022. The federal government imposed the tax on businesses and individuals in provinces with no federally approved carbon pricing plan. In those provinces, the government is handing back carbon tax rebates to most residents. Several provinces have challenged the tax in court challenges without success.

The Conservatives are campaigning against the carbon tax, calling it a "Liberal tax grab" that hikes costs for consumers.

Conservative Leader Andrew Scheer says the Liberals policy announcements lack details and to distract from recent scandals. Scheer spoke to reporters in Thorold, Ont, Tuesday. 0:22

Conservative Leader Andrew Scheer has said his first act in government would be to scrap the tax.

Asked to respond to the Liberal announcement today, Scheer said Trudeau is a "master at improv" and accused the Liberals of making up policy on the fly without providing details on how it would work. He said that, under the Liberals, Canada would fall behind in the climate change fight because of the carbon tax that he says is driving up the cost of living for Canadians.

"We are committed to the targets that we signed on to. That is our plan and our plan gives the best chance to Canada of succeeding," he said during a campaign stop in Thorold, Ont.

The NDP has said it would keep carbon pricing in place, double funding for disaster mitigation caused by climate change and create 300,000 new green jobs in infrastructure, transit, housing and renewable energy as part of its environmental plan.

The Liberals are promising to push Canada to net-zero emissions by 2050. NDP Leader Jagmeet Singh is critical of the new plan saying, "no one believes that Mr.Trudeau is actually going to follow through on those commitments." Singh spoke to reporters in Winnipeg Tuesday. 0:40

NDP Leader Jagmeet Singh accused Trudeau of offering "nice words" and "pretty promises" that are not backed up by action.

"No one believes that Mr. Trudeau is going to actually follow through on those commitments," he said during a campaign stop in Winnipeg. "We believe that we have to take action and now we are committed to moving away from fossil fuels. We know the future for our country and for the world is a future where we are not burning carbon for fuel."