Speaking at the United Nations' Climate Change Conference in Bonn, Germany, businessman Michael Bloomberg and California Gov. Jerry Brown unveiled a plan Saturday for a coalition of U.S. cities, states and businesses to meet America's commitments to combat climate change as federal support from the Trump administration stalls on the issue.

The group called "America's Pledge" released a report detailing how local and state governments as well as private companies will work to meet the U.S.' pledge on climate action stemming from the Paris climate accord, from which Trump has said the U.S. will withdraw.

"The American government may have pulled out of the Paris agreement, but the American people are committed to its goals, and there is nothing Washington can do to stop us," the former New York mayor said.

Syria announced earlier this week at the COP23 conference that it would join the 2015 pact, leaving the U.S. as the only country out of the agreement once it can formally withdraw.

Speaking at the meeting, Brown said the U.S. federal system allows states and cities to have "real power" to act on climate.

Although Brown has been a vocal supporter for climate action, his speech in Bonn was interrupted by anti-fracking and indigenous peoples' rights groups. Some demonstrators shouted "keep it in ground" and "indigenous peoples are the solution."

"I wish we could have no pollution, but we have to have our automobiles," Brown said, responding directly to the protesters. "This is one of the reasons why California has the most aggressive goals. No matter what we do, we're being challenged to do more."

More:Mayors pledge to take the lead on fighting climate change

More:U.S. is reducing dependence on fossil fuels even without Paris climate agreement

More:In Trump rebuke, Bloomberg pledges $15 million for Paris climate agreement

Bloomberg and Brown's group consists of 20 states, 110 cities and more than 1,000 businesses that represent what would be the third-largest economy in the world if it were a country, according to the report.

"We should have a seat at the table," Bloomberg said, calling for non-federal actors like U.S. cities, states and businesses to be allowed to work with other countries on climate action.

The group hopes to reach the Paris goals by setting renewable energy targets for cities and states, promoting renewable energy use for corporations and investing in technology and innovation that accelerates decarbonization of the economy, among other strategies.

The Paris deal aims to reduce global greenhouse has emissions to curb global climate change. However, Trump has called the pact "draconian" and "onerous."

Given current pledges and without U.S. government support, commitments from the U.S. to the Paris pact would not be met, Bloomberg and Brown's group said in its report. However, they hope to expand their actions in order to reach the goals.

"We cannot underscore strongly enough the critical nature of federal engagement to achieve the deep decarbonization goals the U.S. must undertake after 2025," the report said.

The U.S. is the second-largest carbon dioxide-emitting nation on the planet after China, according to the European Commission. According to a massive report released this month by the government's top scientists, human activity, especially greenhouse gas emissions, is the main cause of the recent trend of global warming.

"What we're doing is relatively limited to existential threat that we face," Brown said. "We need to do more."

Contributing: Doyle Rice

Follow Ryan Miller on Twitter @RyanW_Miller