Trump was cajoled for three days - first in Brussels at meetings of North Atlantic Treaty Organisation and the European Union, then in Sicily for G-7 - but will leave Italy without making clear where he stands.
Trump has at times seemed to downplay concerns over climate change.
German Chancellor Angela Merkel, at the conclusion of a G7 summit in Sicily has revealed that a debate between leaders over climate had been "very unsatisfying", noting that the United States had been totally isolated in its refusal to commit to the 2015 Paris climate agreement.
A final G7 communique on Saturday said that all member countries - except the United States - had reaffirmed their "strong commitment" to abide by the 2015 Paris climate agreement to rein in greenhouse gas emissions.
The stalemate on climate change was mirrored by divisions between the USA and the other G7 countries over trade and migration at the annual summit, described by officials as the toughest in years.Delegates worked long into the night in an attempt to reach a compromise on the closing statement to be issued later Saturday.
The Paris agreement is broader than any previous climate deal. An official announcement is yet to be made.
But Trump can pull out of Paris, an agreement Putin has never liked, because it means a large fraction of Russia's fossil fuel reserves would remain in the ground, unable to provide vast revenue for him and the Kremlin.
Prime Minister Voreqe Bainimarama's numerous calls for US President Donald Trump not abandon the Paris Agreement will be answered this week.
EPA staff are quietly working with outside supporters to place op eds favoring withdrawal from Paris.
Trump's response on his return to the White House on Sunday, even as he and his family are lawyering up for upcoming investigations: It's all fake news.
The Group of 7, or G7, is comprised of the United States, Canada, France, Germany, Italy, Japan, and the UK; the European Union also participates.
They were right to be concerned.
French President Emmanuel Macron also chimed in on the climate issue, praising Trump's "capacity to listen".
The final G-7 statement, issued after two days of talks in the seaside town of Taormina, said the U.S. The U.S. hasn't decided yet.
The White House did not immediately respond, but Director of Strategic Communications Hope Hicks said, "I think his tweet was clear".