A UC Berkeley climate scientist very publicly resigned as director of the Berkeley Atmospheric Sciences Center this week after the center refused to host a speech by a scientist who has criticized affirmative action.

Berkeley Department of Earth and Planetary Science professor David Romps announced his resignation on Twitter on Monday, explaining the decision in a lengthy thread, to "reduce the odds of being mischaracterized."

Romps's resignation is the latest twist in a brouhaha that's roiled the world of American scientists, sparking intense debate over the intersection — and, some say, collision — of free speech and social justice activism.

It began when MIT canceled a planned speech by geophysicist and climate change scientist Dorian Abbot over Abbot's published views on diversity, equity and inclusion initiatives. The speech was to be on scientific topics, and was not to address Abbot's views on affirmative action.

Romps said he then proposed inviting Abbot to give his science talk to the Berkeley center — and thus "reaffirm that BASC is a purely scientific organization, not a political one" — but was rebuffed.

"Excluding people because of their political and social views diminishes the pool of scientists with which members of BASC can interact and reduces the opportunities for learning and collaboration," Romps wrote on Twitter.

"More broadly, such exclusion signals that some opinions — even well-intentioned ones — are forbidden, thereby increasing self-censorship, degrading public discourse, and contributing to our nation's political balkanization," Romps went on.

MIT had canceled Abbot's speech after an outcry over the political views the scientist had expressed in videos and published writing.

"'[D]iversity, equity and inclusion' sound just, and are often supported by well-intentioned people, but their effects are the opposite of noble sentiments," Abbot and Stanford professor of accounting Ivan Marinovic co-wrote in a Newsweek opinion article published in August.

"DEI violates the ethical and legal principle of equal treatment," the scientists argue. "It entails treating people as members of a group rather than as individuals, repeating the mistake that made possible the atrocities of the 20th century."

Romps is among numerous scientists and academics speaking out about Abbot's case — from both sides of the issue. And the New York Times spoke with scientists who supported and opposed including Abbot in scientific discussions and forums.

Williams College geosciences professor and department chair Phoebe Cohen challenged the "idea of intellectual debate and rigor as the pinnacle of intellectualism," arguing to the paper that this standard was born of "a world in which white men dominated."

Cohen told the paper she wasn't comfortable allowing Abbot to address fellow scientists on scientific topics, because universities should only invite speakers who share their values.

The director of Princeton's James Madison Program in American Ideals and Institutions, Robert George, on the other hand, opposed what he called the "politicization of science."

"MIT has behaved disgracefully in capitulating to a politically motivated campaign," George told the Times. George invited Abbot to give the speech he'd planned for MIT at Princeton instead.

Meanwhile, the Times quoted Abbot himself as saying, "We're not going to do the best science we can if we are constrained ideologically."

Romps said he'll step down as director of the Berkeley Atmospheric Sciences Center at the end of the year, or sooner if a replacement is ready.

"The stated mission of BASC is to serve as 'the hub for UC Berkeley's research on the science of the atmosphere, its interactions with Earth systems, and the future of Earth's climate,'" he wrote in his Twitter announcement.

"I believe that mission has its greatest chance of success when the tent is made as big as possible," he continued, "including with respect to ethnicity, gender, age, disability, sexual orientation, religion, family status, and political ideas."