Prime Minister Justin Trudeau was the final leader to meet privately with German Chancellor Angela Merkel on Friday prior to the official start of the G20 summit in Hamburg.

The two spoke briefly about Trudeau's children for the cameras before going behind closed doors for a 30-minute private meeting to discuss the Comprehensive Economic and Trade Agreement (CETA) awaiting provisional application by Canada and the European Union, as well as strategies to get as many other leaders as possible on board Merkel's energy action plan.

The working paper, put forward by Merkel as part of her G20 presidency year, is expected as an appendix to the G20 official communique, the document the leaders will sign declaring what was decided in the meeting.

Trudeau told the German newspaper BILD on Thursday his aim with Merkel is to always find out how she thinks Canada can help.

"We are not a big, big country in terms of our weight, but we have an ability to get certain things done," he said.

"Word is she feels we can or should be doing a little more. Whether it's encouraging friends and neighbours to have a different take on things, or being partners on multilateral engagements, like with NATO country Latvia, holding the eastern border."

Prime Minister Justin Trudeau shares a laugh with Mexican President Enrique Pena Nieto, centre front, as Italian President Paulo Gentilonie, left, and South African President Jacob Zuma, right front, and India's PM Narendra Modi, right, look on during the family photo at the G20 summit Friday in Hamburg, Germany. (Ryan Remiorz/Canadian Press)

Helping with friends and neighbours of course is a reference to U.S. President Donald Trump.

Trudeau has been more careful than some other world leaders in criticism of Trump, and many other world leaders or their officials have leaned on him to try to reach out to the U.S. president.

"I expect that there will not be perfect unanimity. But I think we will find common ground in a number of areas," Foreign Affairs Minister Chrystia Freeland told Canadian reporters.

"All of us knew going into this summit meeting that the U.S. position [on climate change] was different. And the U.S., to give them credit, have been very clear about their position," she said. "No one is trying to hide that difference."

"That is the choice of the democratically elected government of the United States, and we need to accept that ... even as we press ahead with our own clear and sovereign policy working energetically together with partners who share our view on [the Paris climate change accord]," Freeland said.

Freeland said there are a lot of other issues, including environmental based, that they can work on with the U.S. She wasn't keen to portray Canada as a go-between amid U.S. and European tensions.

While Trudeau is playing a leadership role, she said, "our European partners are incredibly effective international diplomats and they are very effective at having direct bilateral relationships with all the countries with whom they need to have bilateral relationships."

All but Trump may sign on

Merkel and Trump — who met privately themselves Thursday — have a difficult relationship and the tensions between the two have threatened to overshadow the G20 meetings, particularly as it relates to getting agreement on climate change.

At the G7 meetings in Sicily in May, Trump refused to agree to the climate change language in the communique, making it a six against one scenario.

Merkel's energy plan is a separate document, the working draft of which includes language on everything from fossil fuel subsidies to requirements for companies to disclose the climate impacts of their investments and business practices.

For Merkel, getting 19 of the G20 leaders to sign the document would be a tremendous political success in her battle with Trump but doing it is no sure bet.

Even a back door effort to influence Trump on climate change seems to have failed thanks to protests.

Merkel scheduled a tour of the German climate change centre in Hamburg for G20 spouses. The centre uses supercomputers to model climate change impacts around the world and First Lady Melania Trump was to have been part of it.

Sophie Grégoire Trudeau and son Hadrian leave a ship after a boat tour during the spouses program on the first day of the G20 summit in Hamburg. (Michael Probst/Associated Press/pool)

However Melania was unable to leave the residence where she was staying Friday thanks to violent protests which have left hundreds injured and required the Germans to call in even more than the 20,000 police initially on hand to try and keep the peace.

Trump, Putin to skip climate talks

Trump and Russian President Vladimir Putin weren't part of the Friday afternoon discussion on climate change.

German government TV shows quick impromptu leader meet-and-greets 0:26

Their much-anticipated first official bilateral meeting since Trump took office was planned at the same time, leaving German officials frustrated and angry.

Russia is one of the countries observers fear may be weakening its resolve on its Paris commitments in the wake of Trump's decision to withdraw from the Paris climate change agreement.

Thus far 152 of the 197 countries which signed the Paris agreement in 2015 have ratified it, including Canada.

Russia is not one of them.

Celine Bak, president of Analytica Advisors and senior fellow with the global economy program of the Centre for International Governance Innovation, said there is a lot in the plan everyone should be able to agree with, even Trump.

That includes emphasizing the role the climate change plan can play in infrastructure investment. Trump has made a $1 trillion pledge to build infrastructure in America.

"The connection between sustainable development and infrastructure is a bridge to Trump," she said.

"References to infrastructure and clean technology, those are things the United States administration can support."

What the document will certainly not contain is any reference to a price on carbon, which has been a Trudeau policy opposed by the opposition Conservatives at home.

Bak is hopeful the leaders will also agree to language that pushes what is known as climate finance disclosure, which calls on businesses to disclose the climate change impact of their activities as part of investment decisions.

Trudeau also held bilateral meetings Friday with French President Emmanuel Macron and Indian Prime Minister Narendra Modi.

After shaking hands with Trudeau, Macron said G20 leaders will talk about climate change "especially when some people are doubting it."

Modi also spoke during their brief time in front of the press about India's common ground with Trudeau.

"We see both countries are going in the same direction and in this international forum I think the leaders and everyone saw that we were of the same wave," the Indian prime minister said.

He meets with Mexican President Enrique Pena Nieto on Saturday.