Mulcair will make the announcement at a town hall meeting in Toronto.
The NDP has already promised, during campaigning for the Oct. 19 federal election, that it will establish a national cap and trade system to make big polluters reduce their greenhouse gas emissions.
But the detailed plan will show that an NDP government won't impose that national plan on provinces like Alberta, B.C., Ontario and Quebec that have developed their own systems to control emissions.
Instead, it will allow the provinces and territories to opt out as long as their carbon pricing plans are equal to or better than the federal objectives.
The NDP has faced a lot of questions about how it would impose a national cap and trade system on provinces that have already spent money and time developing their own plans in the last 10 years.
Quebec has an operating cap and trade system. Ontario is in the process of developing a similar one. B.C. has a carbon tax, and Alberta has just introduced a new rules to double its levy on carbon and make the oilsands industry cut the emissions intensity of each barrel of oil.
The Conservatives have taken a sector by sector approach, but have faced criticism for their lack of national regulations to control the country's largest source of emissions — the oil and gas industry.
Revenues to be put back into provinces
The NDP plan would be developed in collaboration with the provinces, territories, cities and indigenous governments.
Revenue raised by putting a price on carbon will be plowed back into the provinces to help them cut greenhouse gases.
Sources say the environment announcement is big part of the "global leadership" focus of Mulcair's election campaign this week.
He will take part in the "Munk Debate on Canada's Foreign Policy" in Toronto on Monday.
Mulcair will then head north to Iqaluit to talk about his party's environment platform later this week — an area of the country that is already feeling the effects of a changing climate.
It's also the riding of Conservative incumbent Leona Aglukkaq, the federal environment minister.
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