Premiers from two of the country's largest provinces say the federal government should reconsider its promise to enact more ambitious greenhouse gas emission targets.

The Harper government set a target of a 30 per cent reduction in greenhouse gases from 2005 levels by 2030. The Trudeau government has said its reduction targets will go much further, something Environment Minister Catherine McKenna reaffirmed in an interview with CBC's Chris Hall.

"At this point we have to be realistic and we have to recognize that we're not on track to meet the targets that are in place. We better figure that out and then we can talk about how we can do more, even more than that," Ontario Premier Kathleen Wynne told CBC Radio's The House after a first ministers' meeting that focused on efforts to tackle climate change.

Wynne's concerns were echoed by B.C. Premier Christy Clark, who says her province is already struggling to meet its ambitious targets despite having dramatically curtailed fossil fuel consumption.

"We've learned here in British Columbia, with the highest and broadest and most transparent — and only revenue-neutral — carbon tax in North America ,we're still not meeting our targets today," Clark said in a separate interview with The House.

"I don't want to disappoint Canadians. I just recognize from British Columbia's perspective — where we have dropped fossil fuel use while the rest of the country has grown — we still are having a real struggle trying to meeting the targets."

New targets coming, Liberals say

Federal, provincial and territorial officials will work over the next six months to draft a national climate plan that the leaders hope to endorse at another summit in October. McKenna said there will be new targets to announce at that time.

"We know there are a lot of emissions coming from transportation — how do we reduce emissions there? Buildings, how do we make those more energy efficient? So, we're going to go through that exercise and then we will know where we can be with our target, which I've said is a floor … not a ceiling," McKenna said.

B.C.'s premier expressed some reservations about boosting targets in the face of slow progress.

"I think we should try and contain our enthusiasm for reaching ever further before we even know how we're going to get to what we've already said," Clark said.

Ontario's cap-and-trade plan

Ontario is banking on a cap-and-trade plan outlined in the province's most recent budget to help it reach its 2020 target of getting greenhouse gas emissions to 15 per cent below 1990 levels.

The province plans to reinvest the cap-and-trade related revenues on initiatives to cut greenhouse gases, including investments in public transit, clean technology and making homes and businesses more energy efficient.

"The reason we went with cap-and-trade is because the cap portion of the cap-and-trade mechanism is what drives the change," Wynne said.

"That cap goes down every year and so there's pressure on all of us to change behaviours, to use different technology so that we eliminate those megatonnes of carbon."

The leaders are expected to reconvene in the months ahead to discuss a national climate plan. (Jonathan Hayward/Canadian Press)

Both the Ontario PC and NDP have criticized the province's plan.

"Life is getting harder for folks," Ontario NDP leader Andrea Horwath said, accusing the government of forgetting about people who will be stung by the new costs, particularly those paying high heating costs in Northern Ontario.

PC Leader Patrick Brown called the cap-and-trade plan a "cash grab" and said he fears the Liberals are taking advantage of people's desires to stop climate change to raise money for pet projects.