WASHINGTON, D.C.—Tens of thousands of science supporters streamed through a steady rain to rally at the foot of the Washington Monument Saturday to demonstrate their support for policies grounded in science, including climate change action.

As they stood in long lines to pass through security gates onto the grassy mall just south of the White House, the demonstrators talked about deep discomfort with the policies of the Trump administration.

They said they were alarmed not only by the administration's overt denial of mainstream climate science, but by what they saw as a disrespect for the fundamental values of science and its contribution to society.

The marchers came from practically every branch of science, from the most familiar to the most obscure.

The March for Science, which attracted support from many of the nation's most prestigious institutions, occurred on Earth Day and kicks off a week of teach-ins, demonstrations and other grassroots activism culminating in the People's Climate March on April 29, which is expected to draw even bigger crowds.

Local marches were held around the nation and around the world. In Portland, Maine, Elke Perks, a science teacher at a local charter school, said she marched out of concern for the "squelching" of science.

"It's unacceptable, and it's not American," she said.

The overriding message from interviewing scores of people attending the march in Washington was that the want government policies built on evidence and reason, not ideology. Even as they professed nonpartisan ideals, they're worried that the government under Donald Trump is moving in a different direction.

Many protesters came from out of town, even though there were mirror events in cities around the nation and across the globe.

Just as striking was the diversity of researchers who said they are actively engaged in climate science.

Climate change cuts across almost every scientific discipline—astronomy, meteorology, biology, chemistry, physics, medicine, mathematics, economics. And the denial of the consensus that has been built from every way of looking at the problem is of deep concern to those attending this march.

Not all of them participated because of the climate crisis—many were worried about public health, funding for education, or the like. But not a single person interviewed was unaware that climate science is at risk. For many, this was the main reason they travelled to Washington this weekend, or if they live here, that they come downtown with their lab-coat-white ponchos and their hand-painted signs.

Richard White, who came from Baltimore with his wife Jean Engelke, said his own work on the Hubble space telescope was not threatened, but that he was there in "solidarity" with fellow NASA scientists, given signs that the space agency's earth observation work is threatened.

Gabrielle Bueno. Credit: John H. Cushman Jr./InsideClimate News

For Gabrielle Buono, a Rochester University undergraduate studying primate cognition, climate change is just one element of species conservation, where she hopes her career will take her.

Some of them were not scientists at all—just ordinary citizens, like Kevin Davies, wearing an Einstein wig, who said he simply wanted to let his government know that science matters That includes climate science, said Davies, who said his trip from Philadelphia was partly inspired by the Trump administration's climate policies. "If you make light of that, you make light of all of science."

Kevin Davies. Credit: John H. Cushman Jr./InsideClimate News

Two youngsters, Aden and Toby D'Amore, the sons of physicians, said their trip to Washington "was a family idea."

"I don't want Trump to screw up the world," Toby said.

Even though the march was billed as non-partisan, most of the people interviewed on the streets said they were alarmed by the Trump administration's policies and were inspired to take political action.

"I was really, really crushed by the election," said Julia Salas, a local college student whose mother came to town from California to join her for the march.

At the Washington event, Trump's record was invoked by speaker Shawn Otto, author of the 2016 book, "The War on Science," and co-founder and producer of the U.S. Presidential Science Debates. The online forum was the only place Trump answered questions on climate and science during the presidential campaign.

"Attacking science is attacking democracy. Denying Science is denying democracy. Rejecting science is rejecting democracy," Otto told the crowd. "We say to our elected leaders: The evidence shows that global warming is real that and vaccines do not cause autism, that research drives prosperity, there are no such things as alternative facts. If you want to lead, Donald Trump, you can't do it with your brain tied behind your back."

In Chicago, marchers gathered near Chicago's Millennium Park, then streamed down toward the city's Field Museum of Natural History. About 700 employees of the museum were among the nearly 50,000 people who turned up.

Many of the marchers in Chicago held signs supporting the Environmental Protection Agency and its Region 5 office in particular. The office, based in Chicago, covers six midwestern states, and recent reports have said it could be shuttered. (The EPA has denied those reports.)

The march in Washington drew a lot of support from people who work on science inside the Beltway, but federal financing for science is so pervasive that threats to science funding are felt all over the country.

Michael Parmacek, the chair of medicine at the University of Pennsylvania, was in Chicago for a conference, but came out to the city's march. Parmacek, a former board member of the National Heart, Lung and Blood Institute at the National Institutes of Health, said the Trump administration's proposed slashing of the NIH budget is already having a chilling effect on research.

"Everyone's scared to death," he said.

ICN reporters Sabrina Shankman, Georgina Gustin and Marianne Lavelle contributed to this story.