At last, the carbon-tax wave is lapping at Ontario's shores.

The pledge from Canada's most populous province and second-largest emitter of greenhouse gases to unveil its plan to put a price on carbon in 2015 is welcome news.

It's also high time the Ontario Liberals delivered on their long-standing promise to introduce such a measure. The province should table legislation this year.

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When Ontario's as-yet undefined proposal is enacted, Canada's four largest provinces (which are home to 30 million people) will have taken concrete action on setting a price for emissions.

The approaches vary widely, from Alberta's comparatively timid Specified Gas Emitters Regulation, to British Columbia's overarching, revenue-neutral levy on carbon-based fuels, by way of Quebec's bilateral cap-and-trade agreement with California.

Ontario Environment Minister Glen Murray says he's drafting a strategy described as comprehensive, and which he claims will be "real, efficient, effective and economically positive."

Those are laudable goals, and to achieve them Mr. Murray should borrow a page (or 10) from B.C.'s handbook. Under the policies set out in 2008 by then-premier Gordon Campbell, fuels are taxed according to the emissions they generate, with an accompanying – and offsetting – decrease in income tax.

The beauty of the system lies in its simplicity: It slashes pollution, costs virtually nothing, has no adverse economic effects and doesn't target the oil and gas industry.

Ontario might be tempted to embrace a cap-and-trade approach, which could be politically expedient (read: negotiable), but in our view that would be a missed opportunity.

The evidence is in, and the effectiveness of B.C.'s carbon regime is beyond dispute.

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Perhaps adopting a carbon tax can nudge other high-emitting provinces – hello there, Alberta and Saskatchewan – toward seizing the moment.

More immediately, it should permit a grown-up discussion during a federal election year.

Prime Minister Stephen Harper's obduracy regarding carbon taxes is well-documented. But not even the fiercest partisans can ignore good ideas forever. The momentum for more stringent carbon pricing in Canada is building.