The meeting comes at a time of major shifts in the global geopolitical landscape under Trump's "America First" policies.
World leaders intend to try to persuade U.S. President Donald Trump to compromise on climate and trade during the Group of 20 summit in Hamburg, Germany.
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In a joint communique issued on the summit's first day Friday, Brazil, Russia, India and China called on the G20 to push for implementation of the Paris climate accord despite Trump's decision last month to pull the United States out of it.
"We call upon the international community to jointly work toward implementation of the Paris Agreement on Climate Change," the communique said.
"We firmly support a rules-based, transparent, non-discriminatory, open and inclusive multilateral trading system, implementation and enforcement of existing WTO (World Trade Organization) rules and commitments and oppose protectionism."
The meeting comes at a time of major shifts in the global geopolitical landscape under Trump's "America First" policies. The host of G20, German Chancellor Angela Merkel, faces the difficult task of steering leaders towards a consensus on trade, climate and migration — all issues that have become more contentious since Trump entered the White House half a year ago.
Aside from the four emerging market countries, British Prime Minister Theresa May also said G20 leaders would urge Trump to reconsider his decision on Paris.
"I hope they will be able to find a way to come back into the Paris agreement ... I believe it is possible. We are not renegotiating the Paris agreement, that stays, but I want to see the U.S. looking for ways to rejoin it," she told the BBC.
Canadian Prime Minister Justin Trudeau told a German newspaper Friday that climate change was a challenge, but also an opportunity to invest. He added that the same was true of global trade.
"Instead of saying we'll stop trade, we need to create opportunities for smaller companies and protect workers' rights with progressive trade agreements like CETA (Comprehensive Economic and Trade Agreement)," Trudeau said, referring to the EU-Canada trade deal.
The draft G20 agreement acknowledges U.S. isolation on the Paris climate accord, but claims the United States is committed to cutting carbon emissions by other routes, according to The Guardian newspaper.
“The United States of America will endeavor to work closely with other partners to help their access to and use of fossil fuels more cleanly and efficiently and help deploy renewable and other clean energy sources,” the draft said.
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On trade, sources told Reuters that Washington was backtracking on language condemning protectionism that Trump agreed to at a Group of Seven meeting in Sicily in late May.
The final version of the communique will be negotiated overnight by attendants from the 20 participating countries.
Merkel chose Hamburg, the second-largest city in the country, to send a signal about Germany's "openness to the world," including its alleged tolerance for peaceful protests.
Police said violence that erupted during anti-capitalist protests directed at the G20 Thursday continued into Friday. At least 29 protesters were detained and 111 police officers injured, including three officers who required hospital treatment.
"There is quite a delicate balance that Angela Merkel will have to navigate in a way, because it is not clear that being confrontational won't just create even more of a credibility problem for G20 cooperation," Indonesian Finance Minister Sri Mulyani Indrawati told the Reuters in an interview.