Details emerging from a United Nations climate conference in Poland drew rave reviews Sunday from U.S. experts despite the Trump administration's controversial vow to exit the Paris Climate Accord.

Delegates from almost 200 countries, including the United States, gathered to set rules to measure, report and verify efforts to cut emissions in line with the 2015 agreement.

Andrew Light, a professor of public policy and atmospheric sciences at George Mason University, was one of the Obama administration’s climate negotiators in Paris. He said the deal cut Saturday, which requires developed and developing nations to follow similar guidelines, was a crucial outcome that could encourage the United States to return to the accord.

Light said it is important that rules on transparency and record keeping be "flexible" for small, poor countries that might struggle to comply. But the rules must be fundamentally the same, he said.

"We wanted an agreement that would make it easy for the U.S. to get back in," Light told USA TODAY. "This is a deal that we would want to be part of, a deal where China, India, other big, developing countries don't have different rules from the U.S. It does make all the countries play by the same rules."

Light stressed that the United States technically is not out of the accord. It takes four years to fully drop out, and President Donald Trump announced the U.S. intentions last year. The United States retains a diminished seat at the negotiating table.

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"We were afraid of backsliding into developed vs. developing nations," Light said. "With the U.S. in a weaker position, no one else can stand up as a peer with China. But (the agreement) landed pretty well."

Michael Mann, a professor of atmospheric sciences at Penn State, said the transparency requirements coming out of Poland are important in light of indications that China’s carbon emissions increased over the past year in a manner that is inconsistent with its Paris commitments.

He said the United States and China reaching agreements with the other nations should "help to create an atmosphere of good faith" and encourage increased emission cutback commitments required in 2020.

That is when countries must show they have met targets set a decade ago for cutting their emissions.

Mann chastised the U.S. contingent at the talks for "colluding" with other big oil-producing states, including Russia, Saudi Arabia and Kuwait, in declining to embrace a report by the Intergovernmental Panel on Climate Change expressing the urgent need to curb emissions immediately to avoid disaster.

The United States and other nations did agree to language expressing “appreciation and gratitude” for the report.

"In summary, I am hopeful that we may have set the diplomatic stage for the fundamental ratcheting up of commitments that will be required at the 2020 conference if we are to avoid catastrophic, potentially irreversible climate change impacts," Mann said.

The U.S. delegation was led by Judith Garber, the State Department's principal deputy assistant secretary in the Bureau of Oceans and International Environmental and Scientific Affairs. The department noted in a statement that U.S. energy-related CO2 emissions have fallen by 14 percent since 2005 while the U.S. economy has grown by 19.4 percent.

The statement said the U.S. decision to drop out of the accord remains unchanged, but the Polish meetings resulted in a "significant step toward holding our economic competitors accountable for reporting their emissions in a manner consistent" with long-held U.S. standards.

"The United States is not taking on any burdens or financial pledges in support of the Paris Agreement and will not allow climate agreements to be used as a vehicle to redistribute wealth," the statement said.