Justin Trudeau and Joe Biden will unveil more aggressive targets for cutting greenhouse gas emissions within the next two months as they forge a North American alliance to battle climate change.

And Mr. Biden is vowing to fight for the release of two Canadians imprisoned in China, warning Beijing that “human beings are not bartering chips.”

The environment and the threat of an increasingly aggressive China were the dominant topics at the first bilateral meeting between the Prime Minister and the U.S. President, held Tuesday afternoon via video link because of the COVID-19 pandemic.

The 90-minute sit-down is Mr. Biden’s first with a foreign leader, part of a campaign to mend fences with allies after four years of belligerence and isolationism under former president Donald Trump. It also included Deputy Prime Minister Chrystia Freeland, Vice-President Kamala Harris and 15 ministers from both cabinets.

Afterwards, Mr. Biden told reporters at the White House that the two countries had agreed to “double down” on fighting climate change with the goal of reaching net-zero emissions by 2050.

“We intend to demonstrate our leadership in order to spur other countries to raise their own ambitions,” he said. “Canada and the United States are going to work in lock-step to display the seriousness of our commitment both at home and abroad.”

Mr. Trudeau told Mr. Biden that “U.S. leadership has been sorely missed over the past years” on climate.

The U.S. and Canada will set new emissions reductions targets before a climate summit Mr. Biden plans to host in April, three State department officials told a background briefing before the meeting. The reductions will be aimed at holding the rise of global temperatures below 1.5 C. Announcing them in April would help set the tone before the global climate summit scheduled for November in Glasgow.

Canada and the U.S. will also work together to draft tougher emissions regulations, the officials said. These could include stricter rules on the transportation sector, such as by mandating more fuel-efficient vehicles, and methane. And the two countries will also look for ways to cooperate on climate adaptation and mitigation measures.

John Kerry, Mr. Biden’s climate change envoy, is scheduled to meet Wednesday with Canadian Environment Minister Jonathan Wilkinson to get the ball rolling on the file, in what Mr. Biden described as a “high-level climate ambition ministerial.”

The Globe and Mail granted the officials anonymity to learn the details of the two countries’ plans for climate co-operation.

Climate was one of six areas in a U.S.-Canada Partnership Roadmap that Mr. Trudeau and Mr. Biden unveiled Tuesday. The plan also contains marching orders for key cabinet ministers to start working together to find ways the two countries can collaborate on the pandemic, the economy, diversity, security and international alliances.

Much of the meeting concerned the detention of Michael Kovrig and Michael Spavor, said one senior Canadian official. China has held the Canadians for more than two years and accused them of espionage, in retaliation for Canada serving a U.S. arrest warrant on Huawei executive Meng Wanzhou.

“Human beings are not bartering chips. We’re going to work together until we get their safe return,” Mr. Biden said afterwards. “Canada and the United States will stand together against the abuse of universal rights and democratic freedoms.”

The President did not offer details on how he planned to pursue the case, but his words are the strongest so far from the U.S. on the matter. One possibility is including their release in a deal resolving the case of Ms. Meng, who is accused of bank fraud for skirting U.S. sanctions on Iran.

Foreign Affairs Minister Marc Garneau expressed optimism about the fate of the two Michaels and noted that the President and his key foreign policy team were “very well informed on the issue.”

“They realize on how very important it is for Canada and I would say that discussion was very, very helpful in terms of our efforts and we will see where that leads,” Mr. Garneau told CTV.

The two sides struck a chummy tone. Mr. Trudeau and Mr. Biden repeatedly referred to one another as “Joe” and “Justin.” The President twice said that the U.S. “has no closer and no more important friend than Canada.” He even joked that he had once spent five years failing to learn French. “Every time I tried to speak it, I made such a fool out of myself,” he said.

Ms. Harris, meanwhile, reminisced about growing up in Montreal, and Ms. Freeland described her pride at Ms. Harris becoming the first woman elected vice-president.

But that friendliness has not prevented tensions from surfacing. The U.S. pushed Canada to increase defence spending in the meeting, the Canadian official said, as part of a renewed commitment to “modernize” NORAD.

Mr. Biden has also left in place Mr. Trump’s policy of not exporting U.S.-made vaccine supplies, leaving Canada with no alternative as its European supply has slowed to a trickle over the past month.

Before the meeting Tuesday, White House press secretary Jen Psaki said Mr. Biden had no plans to let Canada access vaccine doses. “I don’t anticipate that. No,” she said.

Ms. Psaki said the administration was still considering Canada’s request for an exemption from Mr. Biden’s plans for tougher Buy American rules. “We’re still evaluating the application of that and how it will apply. I don’t expect him to make any commitments during the meeting today,” she said.

Mr. Garneau said the Prime Minister did not ask the President to allow exports of vaccine shots from U.S. plants.

The Globe and Mail, February 23, 2021