Broadcaster Aoibhinn Ni Shuilleabhain will be marching in solidarity with US scientists who are desperately trying to persuade Donald Trump to change his stance on global warming.
The TV presenter and scientist said she had written about the subject and felt very strongly about it.
"The fact is Donald Trump isn't really looking at the evidence that scientists have given to him about climate change," she told the Herald.
"It's quite worrying and I think it's something that we need to be very careful about.
"We have to look at what science is telling us about global warming and about climate change."
Organisers of the international March for Science describe it is an "unprecedented global gathering" of scientists and science enthusiasts joining together to acknowledge the vital role it plays in our lives.
Last week, the American president visited the US Environmental Agency to announce an executive order unravelling Barack Obama's climate change plan. Environmentalists condemned the move.
Ms Ni Shuilleabhain, who also lectures at UCD, said she had her sign and T-shirt ready for the march in Dublin on April 22, which will start in Grand Canal Square.
Around 200 people have so far said they will attend the march on the event's Facebook page.
"In a world of alternative facts, we have to really look at opinion versus evidence," she said.
"I think that that's something that's really important. This march will be happening in various countries around the world and I think it'll be a fun one in Dublin."
The former Rose of Tralee was speaking at the launch of a new eco explorer trail at Dublin Zoo in partnership with SSE Airtricity.