Opening session of the COP 23 UN Climate Change Conference in Bonn Thomson Reuters By Environment Correspondent Alister Doyle

BONN (Reuters) - A coalition of U.S. cities, companies and other groups said on Thursday that many in the United States remained committed to the 2015 Paris climate agreement despite plans by U.S. President Donald Trump to pull out.

The "we are still in" coalition opened a 2,500-square meter (27,000-square foot) tent pavilion outside a venue in Bonn, Germany, where delegates from almost 200 nations are working on details of the pact aimed at ending the fossil fuel era by 2100.

By contrast, the U.S. government delegation office at the talks covers only 100 square meters.

"There is a tradition of non-partisanship for protecting our planet," said James Brainard, Republican mayor of the town of Carmel, Indiana, at an opening event.

"It is unfortunate we have moved away from it."

Trump, who doubts mainstream scientific findings that global warming is primarily caused by man-made greenhouse gases, said in June he would pull out of the Paris Agreement and promote the U.S. coal and oil industries.

The "we are still in" coalition of states, cities, universities, faith groups and environmental activists, aims to show delegates from other nations at the Nov. 6-17 U.N. talks that many Americans are working to cut greenhouse gas emissions.

It says its signatories represent more than 130 million Americans and $6.2 trillion of annual economic output.

Fiji, which is presiding at the U.N. talks, welcomed the coalition as a "perfect example" of how the Paris accord aims to widen action beyond national governments.

"I am confident that coalitions like yours will scale up because they are noble and inspiring," Inia Seruiratu, the Fijian minister for agriculture and disaster management, told the meeting.

And Jeff Moe, director of product advocacy for Ingersoll-Rand , said the company was seeking to halve its greenhouse gas emissions.

The "we are still in" pavilion is funded by Bloomberg Philanthropies, The Hewlett Foundation and NextGen America.

California Governor Jerry Brown also urged more action on climate change. "Relative to the threat, the urgency is not there ... and nobody is in charge. That’s the biggest problem," he told a news conference in Brussels. Brown travels to Bonn on Saturday.

(Additional reporting by Robert-Jan Bartunek in Brussels; editing by Andrew Roche)