BEIJING — President-elect Donald J. Trump has called climate change a “hoax” created by China and said he would withdraw from the global Paris Agreement to curb greenhouse gas emissions.

That threat has lent new urgency to a question that has loomed over the agreement since it was signed in 2015: whether China will properly report and submit its carbon emissions data for verification.

Like some other nations, China, the world’s biggest polluter, has refused to accept international monitoring of its emissions and says it will provide data to outside observers. In the past, conflicting data about the country’s energy use has raised questions about accuracy.

Under President Obama, American officials worked to pressure China and other developing nations to provide more accurate data, viewing that as a difficult but critical part of establishing clear global benchmarks in climate change policy.