MIAMI, United States - Budget cuts and political assaults on science are expected to draw thousands of demonstrators to the streets in more than 500 cities worldwide Saturday for the first March for Science.
Organisers insist that the demonstrations -- anchored by a major rally in Washington on Earth Day, April 22 -- are not aimed specifically at US President Donald Trump or any political party.
Rather, they say, the goal is to defend the vital role of evidence and scientific research when formulating public policies, and to speak out against travel restrictions that prevent the free flow of information and expertise.
"The organisers of the march have taken great pains to say this is not partisan, it is not about any particular public official or political figure," Rush Holt, a physicist and former US congressman told reporters on a conference call, noting that scientists are "often reticent" to wade into the political fray.
"For years now, going back far before the election of last fall, there has been a concern among scientists and friends of science that evidence has been crowded out by ideology and opinion in public debate and policy making."
Holt, who heads the American Association for the Advancement of Science, described the trend as "appalling" and said it has driven anxiety to new heights.
The idea for the science-specific march arose during the Women's March on January 21, which drew more than two million protesters into the streets worldwide in support of human rights, he said.
"Scientists started breaking out spontaneously in the Women's March," and several of them connected on social media to forge the plans for a demonstration in support of science, he said.
Trump 'catalysed' march
In the months and years prior to the 2016 election, Trump declared climate change a hoax perpetrated by the Chinese, but since taking office he has delivered mixed messages regarding his views on global warming.
He has signed, however, an executive order to roll back environmental protections enacted by his predecessor Barack Obama, and has nominated climate-science skeptics to top posts in his administration.
Trump has also kept people guessing on whether or not the United States will remain committed to the Paris Climate Accord of 2015, which called for curbing fossil-fuel emissions.
Media reports have pointed to deep divisions within his administration on the matter and no announcement is expected before May.
One of Trump's most alarming moves, according to many scientists, was his budget proposal -- yet to be approved by lawmakers -- that would slash funding for the National Institutes of Health and would eliminate one third of the staff at the Environmental Protection Agency while boosting spending on the military.
This decrease in research funding could "prevent an entire new generation of scientists from ever getting started," said Nobel laureate Carol Greider, professor of molecular biology at Johns Hopkins University.
Lydia Villa-Komaroff, a molecular cellular biologist and honorary national co-chair of the March for Science, said the problem is not new, and that federal support for research has been declining since the 1960s.
"I think it is fair to say that this administration catalyzed the happening of this march, there is no doubt about that," she told reporters.
"But it is nonpartisan. It is aimed not only at both sides of the aisle, where there are people who are dismissing the use of evidence in decisions and policy, but at the public at large where there seems to have become this disconnect between what science is and its value to society."
A 2009 Pew Research poll found that most scientists identify as Democrats (55 percent), while 32 percent said they are independent and six percent claimed to be Republican.
Celebrities set to appear at the March for Science in Washington will include the musician Questlove of the hip-hop group The Roots, and television personality Bill Nye the Science Guy, who currently heads the Planetary Society.
The US capital rally begins Saturday at 8:00 am (1200 GMT), and will be capped with a march from the National Mall to the Capitol at 2:00 pm.
More than 500 satellite marches are planned across the United States and worldwide, including in Australia, Brazil, Canada, many nations in Europe, Japan, Mexico, Nepal, Nigeria and South Korea.
For those wondering what to wear, the marchforscience.com website urges scientists to "come in your work clothes -- a lab coat, goggles, a stethoscope, field gear," it said.
"Or just wear your comfortable 'I'm ready to be politically active and send a message about the need for science in policy' outfit."
Elias Zerhouni, president of global research and development at French pharmaceutical company Sanofi and a former director of the US National Institutes of Health, said science "is a universal language driven by facts and reason.
"This is not just an American issue. It is a global issue because at the end of the day we are all tied together on this planet."