But because the Trump administration cannot officially exit the Paris climate agreement until 2020, it also sent a small State Department team to negotiate details of international climate policy, like greater transparency for emissions reporting from China and India.
Environmentalists here said they found Ms. Garber’s message confusing, and a sign of the awkward tightrope that America’s diplomats are walking as they work on a deal Mr. Trump has disavowed.
“The few people in Bonn who were interested in this speech heard a muddled explanation of Trump’s dangerously incoherent climate policy,” said John Coequyt, global climate policy director at the Sierra Club.
Todd D. Stern, the former State Department climate envoy under President Barack Obama who helped design the Paris agreement, traveled to Bonn to tell his former counterparts that he believed America’s absence from the global accord would be short-lived.
He said his message to other nations was “not to let the retrograde, head-in-the-sand conduct in Washington divert you from your purpose and your course and your commitment. It’s too important to let that happen. And I just firmly believe the U.S. will be back in.”
White House officials have declined to say what new and more favorable terms Mr. Trump seeks. Mr. Banks said that was a conversation that Mr. Trump would have to have with other world leaders. He did not indicate when that might occur or if it was on the president’s to-do list.
Mr. Stern said the White House itself was divided on the question of whether or how to find a way back into the accord. “I don’t think it’s clear who are the key decision makers, or who will be the key decision makers on a road that’s three years long,” he said.
In her remarks, Ms. Garber noted that the United States had cut its greenhouse gas emissions 11.5 percent through 2005, thanks to both public policies and private sector innovations in natural gas and solar power. But she pointedly avoided any promises to cut emissions further, as the Obama administration had done under the Paris agreement.
This week, scientists reported that the pace of emissions reductions in the United States likely slowed in 2017. For the world to meet its climate goals, the country would almost certainly need to accelerate its efforts.
“The United States will continue to support a balanced approach to climate mitigation, economic development, and energy security that takes into consideration the realities of the global energy mix,” Ms. Garber said.