When Canada's premiers gather in New Brunswick for their annual summer meetings this week, the main event undoubtedly will be the debut of Ontario Premier Doug Ford.

Officials from multiple provinces expect the country's newest provincial leader to dominate the two days of meetings in scenic St. Andrews. "There's no doubt people are waiting to see how Ford will act," one official said. Another bluntly added: "I'm betting it's going to be Fordapalooza."

Ford already showed himself to be a disruptive force in federal-provincial relations by scrapping Ontario's participation in a cap-and-trade market and slamming Ottawa for its handling of asylum seekers, many of whom have made their way to Ontario after crossing the Canada-U.S. border.

The testy relationship between Ontario and the federal government was on full display at a federal-provincial immigration ministers meeting in Winnipeg on Friday, when Ontario's Lisa MacLeod refused to join her counterparts at the podium for a closing news conference.

Federal Immigration Minister Ahmed Hussen noted MacLeod's absence from the podium and then called Ontario's comments on asylum seekers "irresponsible," saying "it's divisive, it's fear mongering and it's not Canadian."

"The track record of collaboration between Canada and Ontario is being challenged by the new (Ontario) government," Hussen said.

MacLeod later suggested Hussen should "sit down, have a nice cup of tea, calm down a little bit and maybe phone me and apologize for calling me un-Canadian."

New Conservatives change the mix

Canada may want to put the kettle on. Ford is just the latest — and most significant — change to a roster of premiers that creates new challenges for Prime Minister Justin Trudeau's national agenda, most notably on climate change.

When Trudeau and the premiers met in Vancouver in March 2016 to start discussions on a national climate change plan, there were seven Liberal premiers and two New Democrats. The conservative outlier was Saskatchewan Premier Brad Wall.

But now there is a bloc of conservative governments in the middle of the country. Ontario and Saskatchewan are trying to scuttle the carbon tax entirely. Manitoba is balking at fully implementing it.

Officials in other provinces are eager to see if an alliance forms between Ford, Manitoba's Brian Pallister and Saskatchewan's Scott Moe at the premiers' table.

A federal source who spoke to CBC News last week said that shifting federal-provincial landscape is partly behind Trudeau's decision to unveil changes to his cabinet this Wednesday.

Atlantic concerns

There are even signs of stress in the Atlantic provinces Trudeau's Liberals virtually swept in 2015. Prince Edward Island said last week that if Trudeau wants to impose a carbon tax on Islanders he will have to do it himself, as P.E.I. argues it can reduce emissions without it.

"We're fighting for Islanders here. We're saying if the federal government's plan is to reduce carbon, we have a plan to reduce carbon," P.E.I.'s Environment Minister Richard Brown said. "They can impose their tax."

A senior politician in Newfoundland and Labrador grumbled privately that it will fall to the province to sell the Trudeau carbon tax in an oil-reliant economy already crippled by record deficits, a high cost of living and an unemployment rate hurtling toward 20 per cent.

The federal government's climate change plan is facing more and more opposition from provinces. So, who's in? Who's out? <a href="https://twitter.com/VassyKapelos?ref_src=twsrc%5Etfw">@VassyKapelos</a> has the details <a href="https://t.co/CRRaP6LBhu">pic.twitter.com/CRRaP6LBhu</a> —@PnPCBC

New Brunswick Premier Brian Gallant hopes to use this week's meetings to establish a united front on trade. Given the swelling trade war with the United States, Gallant argues the country can't appear to have internal divisions.

On that front, it shouldn't be hard to get a common statement rebuking U.S. President Donald Trump for building tariff walls along the most profitable border in world history.

"I think it's going to be very important, as premiers, to be as united as possible," he told CBC Radio's The House.

"There's a lot more that binds us together than divides us."

But the premiers are still struggling to find common ground on reducing interprovincial trade barriers. Gallant said he hopes the new friction in north-south trade can help accelerate the removal of east-west barriers that still exist more than a year after the Canada Free Trade Agreement was announced.

More new faces to come

Ford, Moe, B.C.'s John Horgan and Nunavut's Joe Savikataaq will all attend their first Council of the Federation meeting this week. There are signs of more changes on the horizon.

Ford defeated and replaced Kathleen Wynne — Trudeau's staunchest provincial ally — with his resounding electoral win in June. Quebec Premier Philippe Couillard faces a tough election on Oct 1 that could lead to the toppling of yet another Liberal premier.

Alberta Premier Rachel Notley is still a staunch Trudeau ally — especially now that the prime minister has forked over billions to ensure she gets her pipeline. But Notley faces a United Conservative Party under former Harper cabinet minister Jason Kenney and has a date with Alberta voters in 2019. Kenney would be unlikely to bring a bouquet of wild roses to a first ministers meeting with Trudeau.

As each new face arrives at the premiers' table, the climate consensus forged in Trudeau's first year in office erodes. It seems almost certain that Trudeau will have to impose his carbon tax on a growing number of provinces covering a significant portion of the national economy — and then perhaps rebate the revenue directly to Canadians instead of transferring it to the provinces.

As one senior federal official suggested to CBC News, that may end up being more politically popular in the long run.

But it all shows the challenge of trying to negotiate an ambitious, long-term national plan — especially when election cycles don't synch up and allies come and go.