Bill Nye, the face of science in US popular culture, has attacked Donald Trump’s “dangerous” dismissal of climate change and planned cuts to research ahead of the first March for Science in Washington DC.

Nye, an engineer and educator known as “the science guy” through his TV appearances, said scientists should unapologetically throw themselves into the political fray as Trump’s administration seeks to dismantle large areas of scientific endeavor, from cancer research to climate analysis.

“We are in a dangerous place right now,” Nye told the Guardian. “Science has always been political but we don’t want science to be partisan. Objective truths have become set aside and diminished and lawmakers are acting like a strong belief in something is as valid as careful peer review.”

Nye is an honorary co-chair of the March for Science, which will see thousands of scientists and their supporters gather in Washington DC on Saturday. More than 600 companion marches will also occur around the world.

Organizers have said that science is “under attack” and that the march, the first of its kind, will remind politicians and the public of the importance of evidence-based policymaking. Some scientists have, however, voiced concern about getting involved in a political fight with Trump.

The Trump administration has proposed cuts to science programs amounting to around $7bn, including cancer research, coastal resiliency work and climate research. This week, Jeff Sessions, the US attorney general, announced the dismantling of the National Commission on Forensic Science, a body that works to improve the accuracy of forensic evidence in criminal cases.

Scientists have also been alarmed by what many see as anti-science comments by Trump’s appointees. Scott Pruitt, administrator of the Environmental Protection Agency, has set about rewriting many of the agency’s pollution rules and has denied that carbon dioxide, a key greenhouse gas, is a primary cause of global warming. This is contrary to the advice of his own agency’s scientists.

“The arbitrary nature of the cuts are worrying,” Nye said. “When they say they are going to cut one regulation for every two, where do they get that number? Are we going to start driving on the other side of the street and not regulate air traffic?

“There is a technique of dismantling government from within, which is the thinking of (Trump adviser Steven) Bannon. They are hiring the least qualified people on the planet to run the agencies, such as Mr Pruitt at the EPA and Ms (Betty) DeVos at the department of education.

“The idea that regulations are inherently bad is misguided. We will be reminding politicians of the importance of science tomorrow.”

Nye spent time with Barack Obama in the Everglades in 2015 to tout the importance of science and action on climate change. The engineer, known for his bow-ties and public debates with opponents, said it was “frustrating” to hear Trump call climate science a “hoax” and see his administration attempt to eliminate climate research.

But Nye said the march and other outreach efforts by scientists could help persuade Republicans of the economic importance of science and avoid the worst of the cuts outlined by the White House.

“The climate change situation is more urgent than ever,” he said. “But if you’re not optimistic you won’t accomplish anything. When conservatives see the economic value of science and innovation, that turns things around.

“The president changes his mind quite frequently. We want to influence the people who influence him. That’s our goal for the march.”