Only five of NATO's 28 members meet the target: Britain, Estonia, debt-laden Greece, Poland and the United States, which spends more on defense than all the other allies combined.
As the two-day meeting in the seaside town of Taormina, Sicily, was drawing to a close, the leaders were also discussing whether to stay with the group's previous position that it could increase sanctions against Russia over its conflict with Ukraine if Russian actions make that necessary.
As well as the stalemate on climate change there were divisions between the USA and other G7 countries over trade and migration at the annual summit in Taormina, Italy, but an official said some progress had been made.
Six world leaders reaffirmed their commitment to the Paris accord, the world's first comprehensive deal aimed at reducing greenhouse emissions.
For example, just one in three Americans who are Republican or lean Republican say they believe that free-trade agreements have been good for the US, according to a poll last month by the Pew Research Center.
Further global sanctions on Russian Federation for its role in the unrest in eastern Ukraine were cast in doubt as Trump arrived at the helm in Washington amid what appeared to be a softening U.S. approach towards Moscow, said the report. He backed away from his tough campaign talk about trade with China after a summit with President Xi Jinping and abandoned his criticism of Saudi Arabia's human rights record following his warm welcome in the desert kingdom earlier this week.
"His views are evolving, he came here to learn and get smarter, " said Gary Cohn, national economic council director, when asked about the president's views on the climate agreement. In preparations for the Trump-Macron lunch in Brussels, the White House team told its French counterpart to limit the meal to no more than an hour and 15 minutes.
North Atlantic Treaty Organisation countries do not pay the USA or North Atlantic Treaty Organisation directly.
But there was no chance for journalists to question Trump, who broke with G7 protocol by not holding a news conference.
Cohn describes the conversation among the leaders was "very robust" and said there was a "lot of give and take". This is unfortunate for the world, but it's even worse for the U.S.
In order to do that, countries pledged to reduce their carbon emissions. Yet, the USA administration continues to drag its feet. The United States have a financial commitment in the "green fund.' I told Trump that (France's) commitment compared to our GDP is bigger than theirs and that they are not the ones who pay the most". Trump, on the other hand, bided the golf cart to carry him to the piazza. It builds upon the UN Framework Convention on Climate Change, and, for the first time, brings all nations into a common cause to undertake ambitious efforts to combat climate change and adapt to its effects.
Climate Interactive, a team of scientists and computer modelers who track global emissions and pledges, simulated global emissions if every country but the USA reaches their individualized goals to curb carbon pollution. Among the three documents the pope presented Trump as a gift was his 2015 encyclical on the need to protect the environment. But Parolin, the Vatican's secretary of state, did make a direct appeal in a broader meeting with the president and his top aides.
The clashes dominated conversations in and around the summit after the first day wrapped up Friday, with Italian Prime Minister Paolo Gentiloni, British Prime Minister Theresa May and German Chancellor Angela Merkel all singling out, with varying degrees of intensity, the USA for getting in the way.