Conservative Leader Andrew Scheer held a town hall-style event in Toronto on Saturday where he was challenged by supporters to offer a “positive message” on the environment.

If elected this fall, Scheer has vowed to stop Prime Minister Justin Trudeau’s carbon tax, arguing that it will make life harder for families without significantly reducing emissions. The Liberals argue that the carbon tax is a necessary measure to protect the environment, and that the cost will be offset by tax credits.

Mark Walsh from Willowdale told Scheer that he “fully agrees” with him that carbon taxes are “just posturing,” but he wanted to know, “What, if anything, would you as a government do?”

“We need a positive message out there,” Walsh said.

Scheer said the environment is “an important issue,” adding, “when we talk about making life better for the next generation of Canadians, the environment is perhaps the key part of that.”

But, Scheer said, “the carbon tax is not an environmental plan.”

“When Conservatives, when we unveil our plan, I can tell you it will be based on a few key principles,” Scheer said. “One is to reward reductions, not punish commuters. It will be based on incentivizing large emitters to reduce their emissions and rewarding individual choices for Canadians … Things like making it easier to invest in making your homes more efficient.”

Scheer also said it’s important for Canada to also take credit for “what we do well here.”

“We don’t do the world any favours if we bring in a tax that chases away investments and jobs and factories shut down in Canada only to pop up in other countries without environmental standards, without access to clean technology, without access to clean energy,” he said.

He offered the example of aluminum manufacturing, saying the world is worse off if Canadian aluminum plants that use renewable hydroelectric energy close down and are replaced by Chinese factories using coal-fired electricity.

Another audience member also challenged Scheer to elaborate on his environmental plan. Scheer did not offer specifics but said there will be announcements in “the very, very near future.”

“The Liberals are very good at symbolism,” Scheer added. “They’re very good at talking the talk, of using the buzzwords, getting their picture taken and government by Instagram. But it’s Conservative governments that have actually delivered real change and real investments in the environment.”

Prime Minister Justin Trudeau was also challenged on the environment at a town hall Friday in Saint-Hyacinthe, Que.

One man asked Trudeau how he could claim to support the environment after his government purchased the Trans Mountain pipeline in B.C.

Trudeau suggested Canadians will be dependent on fossil fuels for the foreseeable future, and Canada needs to get its oil to market.

In December, Minister of Environment and Climate Change Catherine McKenna accused the Conservatives of wanting to “backtrack on climate action.”

She also pointed out that the Canada-U.S. Air Quality Agreement signed between former Prime Minister Brian Mulroney and U.S. President George H.W. Bush to stop acid rain involved a tax on pollution