President Barack Obama meets with Canada’s Prime Minister Justin Trudeau in Manila last November. Trudeau is bringing his star power to the White House this week on his first official U.S. visit. (Susan Walsh/AP)

A youthful, appealing liberal with star power who upset the established political order to win office will dine at the White House Thursday night — and his name isn’t Barack Obama.

Canada’s Prime Minister Justin Trudeau will meet President Obama, in a meeting of two similar politicians, both with strong progressive instincts yet also with a reflexive degree of caution. The two will discuss an agenda that includes trade, climate change, the fight against the Islamic State and coordination in the vast Arctic frontier, where development, shipping and scientific research vie for priority.

Although Canada and the United States are each other’s largest trading partner and though they share the world’s longest border, Obama never hosted Trudeau’s predecessor, the conservative leader Stephen Harper, with an official state dinner, and it has been 19 years since any Canadian leader was treated to the pomp and guest list of a state dinner.

“Relations are very deep no matter who’s in power, but when you have these two leaders who seem to see the world in similar ways and get along at a personal level, it creates a wide highway at many levels,” said John McArthur, a Canadian and senior fellow in the global economy and development at the Brookings Institution.

Joint steps are most likely to come on climate change and protecting, mapping and monitoring the vast sparsely populated Arctic. And the timing couldn’t be more apt. The meeting comes as the Arctic itself is flashing climate-change warning signs. This year the overall extent of Arctic sea ice hit new record monthly lows for January and February, according to the National Snow and Ice Data Center. Moreover, according to NASA, in much of the Arctic, temperatures in January were more than 4 degrees Celsius, or 7.2 degrees Fahrenheit, higher than average, an anomaly that stunned some scientists.

Alaska had its second warmest winter ever, according to the National Oceanic and Atmospheric Administration, and once again, the iconic Iditarod dog sled race suffered from a lack of snow.

Many Americans have turned to Canada as a refuge in times of crisis, whether those who avoided the draft during the Vietnam War or those who now, perhaps in jest, talk of moving if Republican presidential hopeful Donald Trump wins in November. Trudeau, who personally welcomed the first of 25,000 Syrian refugees allowed into Canada at the airport, stands in stark contrast to the GOP candidate’s vow to bar Muslim immigrants and build a wall on the Mexican border.

During an hour-long Huffington Post town hall on Monday, Trudeau made a light-hearted reference to a website called “Cape Breton if Donald Trump wins” that said it would welcome Americans who might want to flee after the U.S. election. Asked to respond to Trump’s views on immigration and national security, Trudeau said “Cape Breton is lovely, all times of the year, and if people do want to make choices that perhaps suit their lifestyles better, Canada is always welcoming an opening.”

But he also added “I’m not going to pick a fight with Donald Trump right now. But I’m not going to support him either, obviously.” Trudeau compared Trump to Toronto’s infamous former mayor, Rob Ford.

“I prefer to trust that my American friends will exercise their democratic rights with a level of the wisdom of crowds that always ends up coming through in a democracy,” Trudeau said. “The reality is that we will work alongside our neighbors and allies regardless of the political choices they make.”

With Obama in office, that is easier for Trudeau. Todd Stern, the State Department’s special envoy on climate change, said that the two sides would jointly endorse the Paris climate accord, a ceiling on emissions from aviation at 2020 levels, and an amendment to the Montreal Protocol to limit hydrofluorocarbons, a particularly potent category of greenhouse gases.

Trudeau met last week with provincial premiers to try to come up with a national framework.

The leaders may also seek to limit black carbon, a type of soot emissions that absorbs light and hastens the melting of snow and ice, particularly in the Arctic, administration officials said.

Jake Schmidt, international climate expert at the Natural Resources Defense Council, said that Canada will likely agree to match the Obama administration’s goal of reducing methane emissions from oil and gas operations by 40 to 45 percent by 2025. Alberta province already has a similar target, but Trudeau is expected to extend it nationwide.

But Schmidt said that it remains unclear how the United States will meet those targets. Existing and proposed regulations would fall short of those targets, he said.

“There’s an element of these meetings where agreeing at the highest levels is important,” Schmidt said. “It keeps the phone lines open. But where are the 12 additional steps you take once leaders show interest?”

There are some issues where even less progress is expected. Trudeau has pulled a handful of Canadian fighter planes out of the battle against the Islamic State, but he has tripled the size of the small Canadian training contingent to 69 soldiers. In a conference call with reporters Tuesday, Mark Feierstein, the National Security Council’s senior director for Western hemisphere affairs, said Canadians “do, in fact, remain an essential partner, and we’re satisfied with their contributions.” The two allies continue to share intelligence.

Trade is another awkward issue. The Trans Pacific Partnership trade pact negotiated by a dozen nations was sealed just before Canadian elections. In the United States, Obama’s best hope for winning passage of the deal might come in a lame duck session of Congress at the end of the year. In Canada, Trudeau is reviewing the deal before submitting it to a parliament he is just starting to do business with.

“The countries are on different time horizons,” McArthur said.

Canada and the United States are also negotiating over softwood lumber, a vital Canadian export. An earlier 10-year agreement has expired. The two countries have, over the past quarter-century before the accord, fought often over the issue, with the U.S. lumber industry seeking U.S. government duties and anti-dumping penalties and Canada challenging the penalties at the World Trade Organization and the North American Free Trade Agreement.

Feierstein offered little hope of an agreement on softwood lumber, saying only that it was “a longstanding and complicated issue” and that the Obama administration was “open to exploring all options with Canada.”

Post staff writer Chris Mooney contributed to this article.