Natural History Museum Director Beka Economopoulos at a rally during the recent American Association for the Advancement of Science meeting in Boston. (Chris Mooney/The Washington Post)

Some of the nation's biggest scientific organizations, including the American Association for the Advancement of Science and the American Geophysical Union, are partnering with grass-roots organizers to plan the March for Science, an Earth Day rally in Washington and cities around the world aimed at defending "robustly funded and publicly communicated science."

The news signals that the effort, spawned from social-media musings in the days after President Trump's inauguration, has officially gone mainstream.

Such coordinated activism is a big change for scientists and the societies that represent them. Researchers have long been reluctant to dive into political debates out of concern that their work will be perceived as partisan. But the community is increasingly worried about eroding public support for science, and it's ready to speak up.

"I've never seen anything like this," said Rush Holt, chief executive of the AAAS. "In the past, there have been marches for one aspect of science or another or for rallies for funding for medical research. ... But this was not organized by any interest group. It's a spontaneous display of concern about science itself."

The March for Science is slated to take over the Mall in Washington on April 22. The Earth Day Network is co-organizing the event, which will involve speeches, a teach-in, musical performances and a march through Washington. Supporters from nearly 300 cities in 30 countries will hold satellite marches on the same day.

The people behind the march are mostly scientists and educators at the beginning of their careers. Few have activist backgrounds, and none has organized an event on this scale. But in the month since the event's conception, they've managed to get some of the biggest names in the American scientific community on board. The march's other major partners are Sigma Xi, the 100,000-member honor society for scientists and engineers, the Entomological Society of America, the climate action advocacy group NextGen Climate America, ScienceDebate.org and the Union of Concerned Scientists.

In addition, organizers say that more than 50,000 volunteers have signed up to help with marches across the globe. In a private Facebook group, more than 800,000 people have said they'll attend an event that day.

“This started as an idea, but it’s rapidly actualizing into a global movement,” Valorie Aquino, one of the march’s three national co-chairs and an anthropology PhD candidate at the University of New Mexico, said in a statement. “Scientific integrity serves everyone, and we need to speak out for science together."

That AAAS and others have joined the effort is a sign of the community's growing dissatisfaction with the "stick to science" mentality.

"Some people for a long time believed that if scientists would just dispassionately provide data, that science would not be politicized," said Michael Halpern, deputy director of the Center for Science and Democracy at the Union of Concerned Scientists. "That turned out to be a misjudgment of colossal proportions." 

At the American Geophysical Union's meeting in December — the first major conference of earth and atmospheric scientists after the election — there was a pervasive sense of anxiety about what the Trump administration would mean for science. The transition team had already sent a letter to Energy Department officials, asking them to name employees who worked on climate-change research. Several of Trump's nominees had previously expressed doubt about the reality of man-made climate change.

Colleagues stood in clusters during the meeting's poster sessions, discussing the developments, debating what they should do.

“We didn't do a good enough job of making sure people knew this is real,” said a NASA researcher who studies Antarctic ice. “I feel responsible.”

But their concerns were still more hypothetical at that point, and a rally to "stand up for science" drew just a few hundred people from the conference of more than 20,000.

Then Trump took office. Subsequent moves by his administration — mandates that several agencies' scientists restrict their communications with the public and an executive order blocking entry to the United States from seven majority-Muslim countries, which critics said would hurt scientific collaboration — outraged and energized many researchers. When a similar pro-science rally was held at last weekend's AAAS Winter Meeting, which draws many of the same scientists as AGU, the crowd was several times as large as the one in December.

"Although some of our members had the usual scientist's hesitation to be out in the public square," Holt said he felt that most supported the idea of a march. "There's energy there and it's not going away."

Still, the political context has made some scientists wary about participating. Theoretical physicist Jim Gates, who served as an adviser to President Barack Obama, told the Guardian that the April 22 event may be seen as simply "Scientists against Trump."

"To have science represented as this political force I think is just extraordinarily dangerous," he said.

But Holt said that the march's organizers and partners have agreed "to make it clear that it’s for science rather than against anyone."

Holt, a nuclear physicist and former Democratic congressman from New Jersey, said he tells his leery colleagues that the march will happen no matter whether they participate.

"And we want it to be a success," he continued. "We want it to be noticed, we want it to fulfill its promise as a rare opportunity to communicate all the things we want to communicate about science — the beauty, the power, the utility. And to communicate that the conditions in which science can thrive must be defended."

He repeated something one scientist told him during the AAAS meeting: "For an opportunity like this, that is so rare and potentially so powerful, how could we not be there?"