There's a new government whistleblower targeting the Trump administration, this time at the Centers for Disease Control and Prevention. A top scientist there, who was its public face of climate science and its effects on diseases, tells CBS News the agency backed away from its fight against climate change, including even using the phrase "climate change," over fears of antagonizing the administration.

The whistleblower is Dr. George Luber, who worked at the CDC for 17 years, and was the head of its climate and health program until last year, when he was reassigned.

Luber was such a celebrated scientist, he hung out with stars like Matt Damon, and was featured in a Showtime special talking about rising temperatures, called "Years of Living Dangerously." "It's a small field but I am one of the world's experts," Dr. Luber said.

Dr. George Luber, who was head of the CDC's climate and health program. CBS News

In late 2016 Luber was organizing a climate change conference. Al Gore was to be the keynote speaker. But right after Donald Trump was elected president, Luber's boss called him in.

Luber recalled, "I was told the optics are not good and that I needed to cancel it."

Correspondent Mark Strassmann asked, "Did he explain what the optics issue was?"

"That the meeting was happening three weeks after the inauguration."

"And that the White House would be unhappy?"

"Yeah," Dr. Luber said.

America's new president had a dim view of Luber's science, referring to climate change as a hoax, "created by and for the Chinese."

Dr. Luber said his boss wanted something else: "Just don't say 'climate change.' Can you call it 'extreme weather?' Can you call it something else?"

Strassmann said, "You're saying that the Centers for Disease Control was suddenly afraid to use the term 'climate change'?"

"Yeah. Absolutely. I was told to use a different term," he said.

In March 2018 the CDC revoked Dr. Luber's badge, phone and credentials. He was escorted off the property. The CDC moved to fire him. He faced more than 30 "troubling allegations," from falsifying timecards to seeming hung over. Dr. Luber refuted all but one charge, and was allowed to stay.

But, he says, the CDC dismantled his climate and health program, which the agency denies.

"The program has not changed, the program is the same. It was just placed in a different administrative unit," said Dr. Patrick Breysse, Dr. Luber's boss at the CDC. He's the senior manager who Dr. Luber said ordered him to scuttle the science conference.

"It wasn't cancelled; we postponed it," Dr. Breysse said.

"You didn't feel any pressure at all?" Strassmann asked.

"No."

"Politically?"

"No."

That conference happened, but without CDC sponsorship.

Strassmann asked, "Were any CDC employees ever told, 'Stop using the phrase "climate change"'?"

"Not to my knowledge," Dr. Breysse replied, "but we did discuss it."

"That you change from 'climate change' to 'extreme weather,' because 'climate change' was more radioactive?"

"We talked about making the change, but we never made the change."

What's unchanged, Dr. Breysse insists, is the CDC's commitment to studying climate science, but without its star, George Luber. Strassmann asked Dr. Breysse why.

"I can't talk about personnel matters, I'm sorry, Mark," he responded.

"Has he been banned from the campus?"

"So, that's a personnel matter that I can't discuss."

"Is the CDC retaliating against him?"

"I'm just not going to comment on that," he said.

Dr. Luber still works at the CDC, but potentially faces up to a four-month suspension. He has to work from home, where he reviews scientific papers unrelated to climate change.

He told Strassmann, "I do not want media attention, I never did with this. Let me do my work."

Dr. Luber's whistleblower complaint is still under review. It also alleges Congress allocated $10 million for climate change research and the CDC illegally spent it elsewhere.

The CDC denies that.