(CNN) A senior official on President Donald Trump's National Security Council appeared on a podcast whose host has promoted claims that some races were less intelligent than others.

A KFile review of Happer's public appearances reveals that in December of 2016, he appeared on Freedomain Radio, hosted by far-right YouTube personality Stefan Molyneux, who in the past has said that blacks were less intelligent than whites because of what he claimed were their differences in IQ. Though racial issues were not discussed, Happer did promote his skepticism about climate change during his appearance with Molyneux.

In the same week, Happer appeared at a conference organized by the conspiracy theorist G. Edward Griffin and on a YouTube channel that has pushed 9/11 conspiracy theories, showing Happer's willingness to be associated with prominent figures on the fringe.

Happer has a history of making controversial comments attacking established climate science. In 2014, Happer compared the "demonization" of carbon dioxide to the treatment of Jews under Adolf Hitler during an appearance on CNBC.

On Molyneux's podcast in 2016, Happer criticized climate scientists by saying they tinkered with models to get the data to line up to prove their theory. Happer said the scientific community was motivated by tribalism and threatened by theories different from their own.

Happer also compared the science of the climate change to the consensus around the eugenics movement in the late 19th and early 20th century. Supporters of the movement believed people inherited things like criminality and mental illness and that these traits could be bred out of the population.

"When you keep hearing about scientific consensus it doesn't mean anything," he said. "There have been scientific consensuses many times in the past. Most of the time they were wrong. A good example of that was the consensus around eugenics. In the early 1900s when there were all these studies, every one of them show that the master race was good old white Anglo Saxon America."

"And so we had these restrictive immigration laws to keep out these low IQ Chinamen, and eastern Europeans, and Italians - that was all nonsense. It was fabricated data, but all the best and brightest people in America subscribed to it," he added. "The presidents of Ivy League universities, Alexander Graham Bell. You couldn't hold your head up if you didn't support eugenics in those days. That was, you know, 1900, 1910, 1920 and it was simply fraud and yet, no, nobody seemed to recognize it was fraud."

Molyneux's podcast has repeatedly hosted a number of far-right and white nationalist figures including Jared Taylor and Peter Brimelow , the creator of the white nationalist website VDare. He has also hosted Faith Goldy, who has questioned if Canada faced a "white genocide" and who was fired from a far-right website after appearing on a neo-Nazi podcast. Lauren Southern, a far-right activist with a history of anti-Islam comments who was denied entry to the United Kingdom, has also appeared on the podcast.

CNN did not find Happer pushed those controversial views himself and in an email to CNN Happer said his appearances were not endorsement of the views of others at Griffin's conference or of Molyneux.

"Over the years I've been asked to discuss my views on climate at a number of venues," Happer told CNN in an email. "My appearances are in no way an endorsement of the host, or of other speakers, particularly on issues not related to climate science."

Other speakers at the conference claimed that the government could control the weather and that the United Nations' Agenda 21 would usurp the American way of life and that scientists were trying to destroy capitalism and national sovereignty. Agenda 21 is a non-binding United Nations plan for sustainable development to combat climate change worldwide that has become the subject of conspiracy theories.

Happer argued in his speech that carbon emissions would be "beneficial" to the planet and help agriculture because plants struggled to grow with low carbon dioxide levels and greater amounts of CO2 in the atmosphere would help crops.

At the conference, Happer also spoke with World Alternative Media, a YouTube channel that has pushed conspiracy theories about the 9/11 terrorist attacks and claimed the government was hiding the cure for cancer and leading a eugenics program to prevent people from staying healthy. In an interview about his talk, Happer said, "The world is made of carbon and to talk about reducing your carbon footprint, that means reducing the footprint of life."

"Why would we want to do reduce the footprint of life? Strikes me as very wrong-headed," Happer said.