TORONTO -- Ontario's Liberal government has done virtually nothing to address climate change beyond boasting about its move to stop burning coal to generate electricity, the province's environmental watchdog said Wednesday.

"For the very last time I hope to say that of course the coal plants was a good thing and caused the greatest single reduction in greenhouse gas emissions in North America," said Environment Commissioner Gord Miller.

"After that, there's very little that we've achieved, and in fact we've gone backwards in areas like transportation. We really have achieved nothing beyond the coal closures."

Minutes before Miller released his report, Premier Kathleen Wynne announced she would re-introduce legislation to outlaw the burning of coal to generate electricity, but some industries will be allowed to keep doing just that.

"We've kicked the coal habit, and now we have to ensure we never have a relapse," Wynne told reporters.

"Climate change is one of the most urgent environmental challenges of our time. Our past achievements alone are not sufficient, and we know that."

Environment and Climate Change Minister Glen Murray, who joined Wynne at her event on the roof of the Toronto YMCA, admitted the Liberals made a lot of announcements about shutting the coal plants.

"The coal plants closure is, I think, a much touted accomplishment because it was the equivalent of taking the seven million cars that run on our roads everyday off the roads," he said. "But it's time to turn the page and move on."

In his annual report, called Looking for Leadership, the Costs of Climate Inaction, Miller said Ontario will meet its 2014 targets for greenhouse gas emissions but won't be able to do the same in 2020 because it has done so little to address the issue.

"The biggest section is the transportation emissions, and that is a section where we've achieved only minuscule changes, and of course the growth in transportation means that our emissions are increasing," he said.

"Emissions will rise again, giving no hope of achieving the further decline necessary to meet the 2020 target."

Miller complained he couldn't find out why the government cut its original target to reduce greenhouse gas emissions from cars and trucks by almost 80 per cent, something Murray also had trouble explaining.

"You'd have to talk to the transportation ministry in more detail about those decisions," said Murray, whose last cabinet job was transportation minister.

Ontario appears to have lost the ambition it once had to address climate change, said Miller as he called on the province to move faster to reduce greenhouse gases in the transportation sector by switching from diesel to electric GO trains.

"We have a huge opportunity because we can electrify aspects of the transportation system," he said.

"There's a number of choices available, but we haven't made any moves."

However, Murray said the government's plan to invest $29 billion in public transit and infrastructure projects, and to electrify GO trains and expand the service, will get more people out of cars, bringing down emissions that contribute to climate change.

"Part of the focus has been to get to regional express rail, to get the electrification of the system," he said.

"We're moving on massive electrification of public transit and I think that's pretty big."

The environment commissioner also said we can expect more extreme weather events more frequently, and warned they will strain the capacity of the insurance industry.

Scientists now use the word mitigation in a different way when it comes to the impact of climate change on our lives, added Miller.

"The implied promise was that if we could mitigate, then things would be OK, the worst could be avoided," he said.

"That is not an option anymore. We are already locked in to bad changes in our climate systems with severe consequences."

Miller was encouraged that Wynne broadened Murray's mandate to add "Climate Change" to his title, which he said implies a significant change in policy.

"If you change the title, in my experience, you are sending out a message that that ministry is going to be restructured and refocused around not just the environment but climate change," he said.