For years, U.S. opponents of climate action used China as an excuse. Why, they asked, should the United States adopt measures to slow climate change that would be overwhelmed by a rapidly growing Chinese economy, fueled by coal plants spewing greenhouse gases?

How things have changed. This year, it is the Chinese government that has continued to embrace bold climate action, while President Trump on Tuesday moved to roll back a signature U.S. climate program aimed at capping emissions from coal plants and other sources — even as his administration is also seeking to slash government funding for research into better renewable technologies.