Like many warriors, Shaye Wolf is ready to march. She says Pres. Donald Trump’s administration is carrying out a “war on science” with proposed cuts in scientific research funding and appointments of climate change deniers to top positions. So Wolf, climate science director with the Center for Biological Diversity’s Climate Law Institute, will be joining this Saturday’s March for Science in Washington, D.C. “I see this as a very wide spread grassroots movement to resist Trump’s policies that put people in danger,” Wolf says. “We have seen over the last few months repeated protests all around the country, and it is inspiring and encouraging that people are standing up.”

Organizers will not predict how many people will come to the National Mall on Saturday or the more than 500 satellite marches that have been organized across the U.S., Europe, Asia, Africa, Australia and South America. Their Facebook page, though, has been “liked” by over 519,000 people and the Twitter account has 347,000 followers. Organizers were inspired by the Women’s March in Washington that followed Trump’s inauguration but felt the January event had little follow-up. They say they are already laying plans to ensure the science march triggers a long-term and effective movement, including recruiting people to run for political office.

“It’s gone from a simple concept to a complicated and pretty deep movement around the world,” says Kathleen Rogers, president of Earth Day Network, which is helping coordinate the events. The basic point, she says, is to champion science and urge political leaders to use scientific evidence to enact policies for the common good. “Science should neither serve special interests nor be rejected based on personal convictions. At its core, science is a tool for seeking answers. It can and should influence policy and guide our long-term decision-making,” the group's mission states.

Although many marchers, like Wolf, are motivated by actions taken by the Trump White House, Rogers says organizers have tried to steer clear of having the march labeled as a protest against the current administration. Science, she says, should not be used as a partisan issue but rather serve as a motivation for individuals to embrace politics. “We want people to engage in public affairs by getting them to run for office or be on the Hill to talk about their science and the importance of scientific integrity.”

The main rally in D.C. begins Saturday on the grounds surrounding the Washington Monument at 9 A.M. Eastern time with a “teach-in” followed by speakers on the main stage an hour later. The march itself will start at 2 P.M. and will head east down Constitution Avenue from the monument grounds to Union Square near Third Street. Individual groups are hosting a variety of programs to complement the main event throughout the week, such as an hour-long training session on how to lobby Congress hosted by the Union of Concerned Scientists on Friday starting 2 P.M. at its D.C. office.

Rush Holt, CEO of the American Association for the Advancement of Science, which is supporting the march, says the events present a unique opportunity to communicate the importance, value and beauty of science. “Scientists and engineers offer the public an open pathway to discovery that has deepened human understanding of the world and advanced innovations that have delivered significant economic benefits,” he says. “It is necessary to protect the rights of scientists to pursue and communicate their inquiries unimpeded, expand the placement of scientists throughout the government, build public policies upon scientific evidence and support broad educational efforts to expand public understanding of the scientific process.”

Wolf says her center will have booths at various marches and will be reaching out to participants to encourage them to keep working. “This is a very important moment and movement that needs to be sustained,” she says. “Long term there is a big fight ahead to defend science and scientific integrity. That is the cornerstone of sound decision-making.”

Shaughnessy Naughton, founder of 314 Action, a group training scientists to run for political office or become directly involved in lobbying, hopes the marches will encourage more scientists to take active roles in politics. Her group is planning training workshops to provide those interested with the tools they need to effectively engage elected officials. “One of the criticisms after the Women’s March was there was no real follow-up, so we are setting up local and college chapters and trying to get folks mobilized after the march,” she says.

Valorie Aquino, one of three co-chairs of the March for Science and a paleoclimate researcher at the University of New Mexico, says it is crucial for scientists to tell their stories and personalize for the public the role science plays in their daily lives. When people make that connection, she says, it should translate into action that drives government decisions.

“After what hopefully will be a really galvanizing day, I hope people will continue to engage,” she says.