Science popularizer Bill Nye told viewers of a popular late-night show that Earth is "on [expletive] fire" while lighting a globe with a blowtorch.

During his appearance on HBO's "Last Week Tonight With John Oliver" on Sunday (May 12), Nye used frank language to talk to millennials about the impacts of global warming on Earth. (Nye's comments are heavily edited here for language; viewer discretion is advised if you watch the video.)

"By the end of this century, if temperatures keep rising, the average temperature on Earth could go up another 4 to 8 degrees ," Nye said to Oliver. (Nye was referring to degrees Celsius; the equivalent change in Fahrenheit is roughly 7 to 14 degrees). "What I'm saying is, the planet's on [expletive] fire."

He explained that addressing climate change means making tough choices in our daily lives to reduce carbon emissions, which are caused by activities such as driving vehicles or burning coal. These emissions produce greenhouse gases that trap heat in the atmosphere — warming the planet up, causing ocean levels to rise as glaciers melt, and increasing the severity of hurricanes and storms.

Nye, adding a few more expletives in his explanation, said none of these options to address global warming come free. So, he urged his viewers to grow up and make tough choices. "I didn't mind explaining photosynthesis to you when you were 12, but you're adults now. This is an actual crisis — got it?"

Oliver ended the segment by telling the audience that he was "absolutely onboard" with Nye's "gritty reboot."

Nye is best known for more family-friendly content, such as PBS's "Bill Nye the Science Guy" in the 1990s and, more recently, the Netflix series "Bill Nye Saves the World." He also is CEO of The Planetary Society, an advocacy group that promotes space exploration.