WASHINGTON: Scientists began staging an unprecedented series of protests worldwide on Saturday to call attention to threats to science and research programmes, especially in the United States, and growing disregard for evidence-based knowledge.
Thousands of people rallied in Australia and New Zealand Saturday in the first of more than 500 March for Science events globally, triggered by concern over the rise of "alternative facts".
Protesters in Sydney wearing white lab coats called on politicians to support the scientific community, carrying banners reading "without science, it's just fiction" and "we need thinkers not deniers".
Even in Germany where they tend to be respected, scientists were preparing to rally in more than a dozen cities including Berlin, Bonn, Dresden and Hamburg.
The march in Washington, timed to coincide with Earth Day, will put Trump's questioning of climate change and proposed cuts to federal science programmes on centre stage.
Participants say the Washington march will be nonpartisan and marks a new frontier for scientists more accustomed to laboratories and classrooms than activism in the streets.
"It has dawned on some of them it is time to speak up," said Rush Holt, chief executive of the American Association for the Advancement of Science. "I wouldn't say that it is fundamentally because of Donald Trump, but there's no question that there's been concern in recent months about all sorts of things."
The White House did not respond to a request for comment.
Trump has called climate change a hoax. His administration is considering withdrawing from the Paris Agreement aimed at reducing global emissions of carbon dioxide and other greenhouse gases.
Trump's proposed 2018 budget calls for deep spending cuts by government science agencies, including a 31% reduction for the Environmental Protection Agency, which is now headed by a climate-change sceptic.
Rally organisers are also worried by what they see as growing scepticism from politicians and others on topics such as vaccinations, genetically modified organisms and evolution.
"It's really the age-old debate of the rational view of the universe against the irrational view of the universe," said Elias Zerhouni, former director of the National Institutes of Health.
Guests at the Washington event will include television personality Bill Nye "The Science Guy", former White House technology aide Megan Smith and Dr Mona Hanna-Attisha, a paediatrician who helped expose the lead water crisis in Flint, Michigan.
But some questioned whether scientists should play a political role, and whether the march would change the minds of Trump, his top aides, or sceptical voters.
"We need to go to county fairs, and we need to personalise the scientific issues we care about," said geologist Rob Young, a professor at Western Carolina University.