WASHINGTON — President Obama is expected to announce on Monday an Environmental Protection Agency regulation to cut carbon pollution from the nation’s 600 coal-fired power plants, in a speech that government analysts in Beijing, Brussels and beyond will scrutinize to determine how serious the president is about fighting global warming.

The regulation will be Mr. Obama’s most forceful effort to reverse 20 years of relative inaction on climate change by the United States, which has stood as the greatest obstacle to international efforts to slow the rise of heat-trapping gases from burning coal and oil that scientists say cause warming.

The president had tried, without success, to move a climate change bill through Congress in his first term, and such legislation would now stand no chance of getting past the resistance of Republican lawmakers who question the science of climate change. So Mr. Obama is taking a controversial step: He is using his executive authority under the 1970 Clean Air Act to issue an E.P.A. regulation taking aim at coal-fired power plants, the nation’s largest source of carbon pollution.

“I am closely watching this. This standard is the real test of how serious the Obama climate action plan really is,” said Qi Ye, director of the Climate Policy Center at Tsinghua University in China. The university is one of about half a dozen institutions that the Chinese government has tasked with immediately analyzing the new rule, according to Chinese experts.