Canada's newly installed Prime Minister Justin Trudeau stayed focused on economic growth and climate change at the G20 summit in Turkey on Sunday, while reaffirming his pledge to accept 25,000 Syrian refugees by year end and delivering a pointed message that Canada is a country that defines itself by its shared values, not its cultural differences. 

He also found time to greet business executives who gave him a rock-star welcome and sought selfie photos as he made his debut on the world stage, and cracked a couple jokes, including one said to have elicited a chuckle from U.S. President Barack Obama.  

In his main remarks, Trudeau told a G20 top-tier business audience that long-term investments in infrastructure and youth are the keys to growth, not a preoccupation with short-term profits.

Canadian Mark Carney, the Governor of the Bank of England, was among those in attendance, along with Perrin Beatty, president of the Canadian Chamber of Commerce and Angel Gurria, the secretary general of the Organization for Economic Co-operation and Development.

Trudeau covered ground that would have been familiar to Canadians following the federal election, including his infrastructure spending plans to stimulate growth.

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Canadian Prime Minister Justin Trudeau, middle, takes part in the official photo at the G20 summit in Antalya on Sunday. (Sean Kilpatrick/Canadian Press)

But he also addressed climate change, calling it a major economic concern. 

"Climate change is a very real challenge, and how we prepare for the increasing pressures on our ecosystems and our resources and our climate will be something that we will be judged on in coming decades and generations," Trudeau said, delivering a message global audiences have not heard from a Canadian prime minister in about a decade. 

Selfie seekers

Even before he spoke, the prime minister was mobbed for selfies at the G20 business and labour panel discussion by dozens of smiling delegates shortly after his arrival. Trudeau willingly posed for several minutes, allowing many personal photos as well as group photos at the foot of a stage, prior to giving his speech.

Not everyone wanted a photo, but many others approached Trudeau as he held court and received warm greetings from a variety of people, including Christine Lagarde, the managing director of the International Monetary Fund.

"This is the best G20 I've ever been to," Trudeau quipped later during a working lunch.  

He also met briefly with Obama and had a warm conversation with the U.S. president, Trudeau's aides said. According to the aides, when asked what he would do first as prime minister, Trudeau indicated he would cut middle class taxes — to which Obama responded laughing, saying that it sounded pretty good. 

Questions about Paris attacks

In his remarks, Trudeau told the G20 gathering Canada was "profoundly saddened" by events in Paris and said Canada would be there for France in the weeks and months to come.

Afterwards, at a photo op with the Mexican president, he was asked by a reporter about the state of Canada's domestic security.

​"The safety and security of Canadians is a priority, for me and for my government," Trudeau said. 

"I've been speaking with the minister of public safety and the various police and security agencies. It's a topic we will be engaging here as well with the other leaders to ensure continued safety for our citizens​."

The remarks were Trudeau's first public comments on the Paris attacks since leaving Ottawa on Friday night. At the time, there was little information about who might be behind the killings.

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Prime Minister Justin Trudeau, second row third from left, takes part in the official family photo at the G20 Summit in Antalya on Nov. 15. (Sean Kilpatrick/Canadian Press)

Fight against ISIS

Since then, French president François Hollande has blamed ISIS for the deaths of 129 people at restaurants, bars, a stadium and concert hall. Several world leaders have responded by insisting on the importance of fighting back against ISIS.

While an official in the Prime Minister's Office has said that Trudeau remains committed to that fight, the Liberal leader has also pledged to pull Canada's CF-18 fighter jets from the U.S.-led bombing mission in Syria and Iraq, and to refocus on training local forces in the region.

However, he has not said when that change will take place. The Conservatives authorized the current effort to continue until the end of March 2016.

In light of the attacks, Conservative interim leader Rona Ambrose has called on the Liberals to immediately reverse the decision on the CF-18s.

Trudeau has also talked about the importance of providing more humanitarian support.

On Sunday, he repeated his pledge to bring 25,000 Syrian refugees to Canada by the end of the year.

Public Safety Minister Ralph Goodale, speaking in Ottawa, told CBC News the federal government faces "logistical challenges" in meeting the ambitious deadline, but is satisfied it can be done without sacrifices to national security or public health.

"Screening is an integral part of the plan and we will make sure that kind of screening, either on the security side or the health side, that the quality and the calibre of the screening is not compromised," he said.

With files from CBC's Catherine Cullen and Chris Hall and The Canadian Press