As he prepares to launch a fact-filled show into a fact-challenged world, Bill Nye, a.k.a. the Science Guy, is looking on the bright side.

“You have to be optimistic,” the author, engineer and television personality said in a phone interview. “You’re not going to solve global problems or address global issues without being optimistic. If you don’t think you can do anything about it, you won’t.”

His new program, “Bill Nye Saves the World,” will premiere as a Netflix original series on April 21. In a statement, Netflix said, “Each episode will tackle a topic from a scientific point of view, dispelling myths, and refuting antiscientific claims that may be espoused by politicians, religious leaders or titans of industry.”

Mr. Nye, 61, will be joined by celebrity guests like the model Karlie Kloss, the actor Rachel Bloom and the fashion consultant Tim Gunn. A Netflix representative said the 13 episodes, each 30 minutes long, will be released all at once.