"We'll demonstrate that we are serious about climate change," Trudeau said following a four-hour working dinner with provincial and territorial leaders.
First minister's meeting is not expected to produce any new national target for reducing emissions - but will set a fresh tone for Canada one week before Paris.
Curbs on oil sands emissions and an end to coal power by 2030 are the key planks of a new, greener, Alberta in a groundbreaking announcement by Notley's government just days before Paris talks.
Does Trudeau need to atone for all Stephen Harper's 'climate fossil' awards? Or merely craft a coherent policy that will put Canada - and the world - on track towards a low-carbon future?