Does Donald Trump believe global warming is a hoax? Neither Trump nor his top aides will say.

After President Donald Trump announced that the United States would withdraw from the historic Paris climate agreement, Trump and his top White House officials are refusing to say whether he believes that climate change is real.

Trump has called climate change a "hoax" multiple times in the past, including in 2014, when he tweeted, "Snowing in Texas and Louisiana, record setting freezing temperatures throughout the country and beyond. Global warming is an expensive hoax!"

Years later, White House officials, from press secretary Sean Spicer to counselor to the president Kellyanne Conway, are dodging questions from reporters about whether Trump still believes climate change is a hoax, or if he agrees with the 97% of climate scientists who say climate change is real and caused by human behavior.

Trump himself dodged the question Wednesday during an event in the White House, when he merely replied "thank you" and left the room when a reporter asked whether he believed climate change was a hoax.

In a background briefing with reporters Thursday afternoon, White House advisers repeatedly declined to answer questions about whether Trump thinks climate change is real. Trump economic adviser Gary Cohn did the same thing an interview with CNN Thursday.

And on Friday on Good Morning America, Conway repeatedly dodged George Stephanopoulos' question about whether Trump believes global warming is a hoax.

"The president believes in a clean environment, in clean air, clean water, he's received awards as a businessman in that regard," Conway said. "And he made very clear yesterday in what he doesn't believe, in that the U.S. government should stay in an agreement that gives us too much of the financial burden, too much risk to these industries where the coal miners, people who work in cement and paper, people who he looked in the eye in place after place, city after city."

Stephanopoulos cut Conway off as she filibustered his question, interjecting to ask once again whether Trump believes global warming is a hoax.

Again, Conway dodged, saying Trump believes in "clean air, clean water."

So Stephanopoulos asked a third time, "does he believe global warming is a hoax?"

Finally, Conway responded, "you should ask him that."