Thousands of people have protested in 500 cities around the world - including five in New Zealand - against what they see as a political assault on facts.
Hundreds of people in New Zealand marched yesterday as part of a global movement prompted by what's seen as the anti-science stance of the Trump administration in the United States.
That includes putting Scott Pruitt in charge of the US Environmental Protect Agency, who denies humans are causing climate change.
The March for Science in New Zealand was held in Auckland, Palmerston North, Wellington, Christchurch and Dunedin.
Auckland University physics professor Shaun Hendy said New Zealand could not solve global warming on its own and it was dependent on other big countries taking leadership.
The US was one of the most important countries politically, scientifically and in terms of its emissions per person, he said.
"If the United States doesn't actually take the lead on climate change then really in New Zealand we're going to be in big trouble, so policies in the United States affect us."
Mr Hendy said New Zealand scientists felt compelled to speak out against the growing rise of alternative facts and the push against scientific knowledge to inform policy decisions.
"We don't see it to the same extent in New Zealand as perhaps we're seeing overseas but it's certainly something we don't want to see take hold here," he said.
Mr Hendy said recent world events had given rise to some extreme views in New Zealand, pointing to the example of the Auckland University European Students Association, which has been accused of promoting white supremacist values.
"We're starting to see some worrying signs that maybe there's a few people in New Zealand that have been emboldened by what's happening overseas but by and large our politicians are pretty good."
However, Mr Hendy said the country's political leaders did need to become better at using science and evidence.
alternative facts 'dangerous'
Victoria University climate scientist James Renwick agrees.
What happened in the US in terms of funding and social change affected the rest of the world, he said.
"The whole loss of faith in science and loss of faith in that kind of rational approach I suppose and this idea of alternative facts is really dangerous.
"It undermines rational discussion and ultimately rational actions and policy at the government level, I think it's really pernicious and could be really damaging globally."
Mr Renwick said he did not see that becoming a problem in New Zealand, but there were people within the government who he said were not so wedded to using scientific evidence for developing policy or making decisions.
"Even a little bit of that can be dangerous stuff, I think, so the situation in the US does kind of give license to people in other countries to push that kind of agenda further," he said.