By COLLEEN BARRY, SYLVIE CORBET and DAVID McHUGH
Associated Press

TAORMINA, Sicily (AP) - The differences are well-known: climate change, trade and migration threaten to throw a summit of the Group of Seven wealthy democracies off its consensus game, with President Donald Trump cast as the spoiler-in-chief. But it may not play out exactly that way, according to long-time G-7 observers.

"It is a forum made for Donald Trump's particular style. It is highly informal, highly interactive and they speak in very colloquial language to each other," said John Kirton, director of the G-7 Research Group at the University of Toronto. "It is the ultimate lonely hearts club. No one understands how tough it is to have the top job except the peers with the top job in other countries."

While Trump has met all of the leaders one on one, this will be the first time all seven are around the same table, including also newcomers Emmanuel Macron of France, Theresa May of Britain and the Italian host, Paolo Gentiloni - forging a new dynamic after a year of global political turmoil amid rising nationalism.

Climate policy promises to be the real buzzkill at the G-7 party. Endorsing measures to combat terror is expected to find easy agreement, especially after the attack on an English pop music concert killed 22 people Monday night. But some of the trust that fuels such meetings was undermined by a leak of British intelligence in the Manchester attack blamed on a U.S. official, annoying British officials. Trump also going against the grain on trade with more protectionist stand.

His pending review of U.S. climate policies and decision not to make up his mind before Taormina has braced environmentalists for the possibility of bland language that says little after years of increasingly stronger commitments to reduce reliance on fossil fuels and emissions of in greenhouse gases under the Paris Agreement.

"What we do not want to see is a false compromise on nothing," said Tobias Muenchmeyer, a political expert for Greenpeace. "We want to see determination and commitment over unity," with the other partners going ahead without the United States.

Trump's attempts to impose a U.S. travel ban on some Muslim countries contrast with Canadian Prime Minister Justin Trudeau's position that immigration is a source of strong, sustainable inclusive growth. Sicily is on the front lines in Europe's migration crisis, the first landfall for most of the more than 180,000 migrants who arrived in Italy last year - and the reason the Italian government chose Sicily as the backdrop for this summit.

Kirton said Trump has demonstrated the ability to come to bilateral agreements, and it is possible that Taormina will yield deals for which he can claim credit at home. But his volatile style could upend even summit decisions.

"It is always possible the president will change his mind even before he lands in Washington and fire off some more tweets," Kirton said.