Appearing Sunday on HBO’s Last Week Tonight with John Oliver, Bill Nye launched into an profanity-laden and hyperbolic rant about climate change, exclaiming “the planet’s on fucking fire!”

“By the end of this century, if emissions keep rising, the average temperature on Earth could go up another four to eight degrees,” Nye said while discussing the Green New Deal, the far-left proposed stimulus package that aims to address global warming and economic inequality. “What I’m saying is the planet’s on fucking fire. There are a lot of things we could do to put it out — are any of them free? No, of course not. Nothing’s free, you idiots. Grow the fuck up. You’re not children anymore. I didn’t mind explaining photosynthesis to you when you were 12. But you’re adults now, and this is an actually crisis, got it?

Safety glasses off, motherfuckers,” he added.

