Two new public marches and demonstrations focused on science and climate change have been scheduled for April. I plan to be at both.

WIRED OPINION About Peter Gleick (@petergleick) is a member of the US National Academy of Sciences, a MacArthur Fellow, and a hydroclimatologist.

A disturbing array of fundamental social and human values are under assault in the United States. These values—basic human rights, amicable international relationships, environmental justice, free speech, separation of church and state, an open and independent media, and more—form the bedrock of what makes our country special. Yet these values are being undermined in an unprecedented assault by the Trump administration and by politicians who see an opportunity for an unprincipled massive power grab.

One tool being used in this assault on democracy is the uninhibited use of lies, false statements, blatant and intentional misrepresentations of fact, and bad science. This is evident in the rejection of the undeniable reality of climate change by many of Trump’s top appointees, the promotion to power of individuals who reject the fact of evolution in favor of pseudoscience and religious fundamentalism, the spreading of bad medical science around the proven safety of vaccines, and the refusal to study the health risks of guns.

I'm a scientist trained in engineering, hydrology, climatology, environmental science, statistics, and more. But more importantly, I'm a citizen who believes deeply in the principles our founders enshrined in the Constitution. Like many others in my broad circles of colleagues, friends, neighbors, and family, I've found the news over the past few weeks to be frightening. I have colleagues in countries targeted by travel and religious bans. My work uses scientific data collected, managed, and now potentially censored or hidden by federal agencies. I see congressional representatives and committees seek out bad science to support predetermined and ideological positions, and then threaten scientists who challenge them.

Scientists aren't great organizers; we're often too focused inward on our work or the fascinating and narrow questions we're trying to tackle. There is an inherent fear that the integrity of our scientific work could be tainted by politics. And there are few rewards and plenty of criticism when scientists express opinions about policy and politics. But when the time comes to speak, to stand up, those of us who can must do so. That time has come. But what can I do?

Call my elected representatives? Here in California, I have the good fortune of being served by two senators, a member of Congress, a governor, and local representatives who mostly mirror my concerns and views. I share my views with them regularly, but my calls to other elected officials are ignored or rejected.

Protest on social media? I'm active on various social media platforms, but I also understand that these are often just echo chambers of like-minded folks. It is a comfort to share thoughts, news, and laments on Twitter or Facebook or elsewhere, but it is important to move beyond them.

Write joint letters with like-minded scientists? I've signed many such letters in the past few years (for example here, here, here, and here) and will continue to do so, but these also have limited reach and influence.

Abandon the public arena? Move overseas until the political winds reverse? Retreat into my science and try to shut out the horrible news? I can't. I work on water and climate challenges in the direct interest of society, including some of the most severe problems facing the planet. When politics threatens fundamental social values and principles, the defense of those values and principles becomes an overriding priority.

So, I will also try to make my voice heard in the street by marching in the upcoming March for Science and the Climate March, scheduled for two consecutive Saturdays in April. I don't know if these public marches will have any effect, but they offer one more avenue for defending American principles and mobilizing awareness. I demonstrated against the Vietnam War—and was tear-gassed for it—in the '70s. I marched in San Francisco against the Iraq war in 2003. And the current threats to society are far worse. These public demonstrations offer an opportunity for all Americans, not just scientists, to stand up for science, objectivity, facts, and truth, at a time when telling the truth is becoming a threatened, radical act.

Most importantly, I also know that this kind of public demonstration is a core value our founders enshrined in the Constitution. For that reason alone, it is also worth exercising. I carry in my briefcase a paper copy of the US Constitution. It reminds me that "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."

So, as a scientist, but really just as a citizen, I'll be peaceably assembling, exercising my free speech, and petitioning the Government for a redress of grievances. Join me.