HAMBURG, Germany — For years the United States was the dominant force and set the agenda at the annual gathering of the leaders of the world’s largest economies.

But on Friday, when President Trump met with other leaders at the Group of 20 conference, he found the United States isolated on everything from trade to climate change, and faced with the prospect of the group’s issuing a statement on Saturday that lays bare how the United States stands alone.

Chancellor Angela Merkel of Germany, the host of the meeting, opened it by acknowledging the differences between the United States and the rest of the countries. While “compromise can only be found if we accommodate each other’s views,” she said, “we can also say, we differ.”

Ms. Merkel also pointed out that most of the countries supported the Paris accord on climate change, while Mr. Trump has abandoned it. “It will be very interesting to see how we formulate the communiqué tomorrow and make clear that, of course, there are different opinions in this area because the United States of America regrettably” wants to withdraw from the pact, she said.