This article is part of a package of special coverage of climate change issues by CBC News leading up to the United Nations climate change conference (COP21) being held in Paris from Nov. 30 to Dec. 11.

Prime Minister Justin Trudeau says he's not only optimistic a deal will be reached during the United Nations climate change conference in Paris, but he's comfortable parts of that deal could be legally binding.

Trudeau touched down in Paris Saturday night ahead of the two-week conference. He meets with French President François Hollande on Sunday.

Leaders and climate negotiators from almost 200 countries are meeting from Nov. 30 to Dec. 11 to try to work out the broadest and longest-lasting deal so far to slow global warming.

Justin Trudeau says around the world citizens are calling on their governments to act on climate change. 0:40

However, the prime minister says it's unlikely that obtaining carbon reduction targets will be mandatory. That's largely because it would be politically impossible for U.S. President Barack Obama to get such legislation through the Republican-dominated Congress.

The one thing we are focusing on now beyond targets, which have time and time been set and not met, is establishing a plan to actually meet those targets. - Prime Minister Justin Trudeau

Trudeau says he believes it could be legally binding for countries to disclose how they are aiming to reach targets.

"That's the balance President Hollande is looking for and certainly what we encourage," Trudeau said Saturday in Malta, where he wrapped up meetings with the heads of other Commonwealth countries.

"I have tremendous faith in Parliament and my friendly opposition leaders to ensure we are held to account for the commitments we make."

Concentrating on a plan

The premiers of Alberta, British Columbia, Ontario, Quebec and Saskatchewan will meet Trudeau in Paris this weekend. It's a chance, as Alberta Premier Rachel Notley says, to show the world they're dealing with a new Canada.

"I think it's just very, very important for people to see that they're dealing with a different thing now in Alberta, and hopefully they'll view our efforts to engage in international trade more positively as a result," she said.

Trudeau will not provide a new greenhouse emissions target in Paris. He has committed to talking to the premiers within 90 days of the climate change summit to set targets.

Environment Minister Catherine McKenna said the past target made under the Conservative government will be used as a minimum, referring to it as "a floor, not a ceiling."

The Conservatives announced in May that Canada's contribution to this year's Paris talks would be a 30 per cent cut in greenhouse gas emissions below 2005 levels by 2030.

Canadian Prime Minister Justin Trudeau speaks with the Canadian Ambassador to France Lawrence Cannon as he walks across the tarmac with his wife Sophie Gregoire-Trudeau and their children Ella-Grace Trudeau and Hadrien Trudeau as they arrive at the airport Saturday, November 28, 2015 in Orly, France. Trudeau is in Paris to attend the United Nations climate change summit. (Adrian Wyld/The Canadian Press )

Trudeau said global warming could have "a catastrophic impact," especially for Canada's Arctic.

"The one thing we are focusing on now beyond targets, which have time and time been set and not met, is establishing a plan to actually meet those targets and that's why it is so important to demonstrate the kind of ambitious

commitments that Canada is making concretely around emissions reductions," he said.

"We are focused on the plan to reduce emissions as much as we are targets."

Trudeau to meet Indian PM

Trudeau will sit down with his Indian counterpart Narendra Modi on Sunday night in Paris to make the case for a comprehensive climate change agreement.

Modi took a pass on Malta, and his country is seen as a significant impediment to a global climate change pact, given India's refusal to rein in its galloping greenhouse gas emissions.

Trudeau told reporters he remains optimistic India will come on board for the post-2020 climate pact being negotiated in Paris.

He said citizens "are going to look very negatively at countries that don't participate."

"For a concrete example of that, we need not look much further than our own story and the difficulty we had getting pipelines built because people didn't believe we were taking our environmental responsibilities seriously."