Climate researchers at this year’s American Geophysical Union meeting in San Francisco spoke out at a rally.

Standing defiant in white lab coats, climate researchers had a message for the Trump administration on Tuesday afternoon, promising to “stand up for science.”

With President-elect Donald Trump appointing climate change deniers to his administration and issuing other implied threats to climate science research, the science community came together outside the annual fall meeting of the American Geophysical Union.

The meeting is the world’s largest gathering of Earth scientists, and this year, one of the main topics of conversation is how deeply the Trump administration may cut federal research funding.

“We will not stand for attacks on science!” Beka Economopoulos, an activist and director of the Natural History Museum said, kicking off the rally full of Earth and space researchers and other activists and supporters. She said in this era of fake news and anti-science rhetoric, scientists need to show a unified front.

Naomi Oreskes, a history of science professor from Harvard University, spoke about this rare gathering of scientists, emerging from their labs and research projects to talk about politics.

“This is a frightening moment,” she said. “We have to get out and explain to people why this science matters.”

She lightly chided her fellow scientists for being complacent and not thinking they have to speak up for research and supporting research funding.

“We have to get out and explain to people why this science matters.”

She spoke about global warming and increased fossil fuels usage in terms she hoped business-minded Trump would understand, “Climate change is going to cost Americans a lot of money.”

Recent appointments to the Environmental Protection Agency and Department of Energy have left the science world reeling, and Trump’s latest comments that “nobody really knows” if climate change is real is a scary wake-up call that his administration might be worse than the George W. Bush years.

The Bush administration supported climate science research but discouraged many scientists from communicating their findings to the public.

Others at the rally spoke about the effects of fossil fuels and the warming of our planet and keeping scientists within government ranks to serve as watchdogs.

Georgia Tech professor Kim Cobb, the head of a paleoclimate research lab, said this past year has been “humbling” for her. With physical evidence of coral reefs dying worldwide and record warm temperatures, she said scientists have to defend and share their work before it’s too late.

She called Trump and his policies “a nightmare scenario.”

Rally organizer Geoffrey Supran, an MIT and Harvard researcher, told Mashable Trump’s acceptance of climate denial is the final straw, pushing usually reluctant scientists to speak out. “Scientists are more angry, more terrified and more determined than ever to hold our leaders accountable,” he said.

As the crowd chanted at one point, when science and research is under attack, “Stand up, fight back!”

Additional reporting by Maria Gallucci.

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