Tesla CEO Elon Musk railed against fossil fuel during a talk-show appearance on Thursday.

Musk called human use of fossil fuels "the dumbest experiment in human history."

Musk's various ventures —electric cars, solar energy, and energy storage — are a testament to his personal investment in sustainable energy sources.



Tesla CEO Elon Musk this week gave an impassioned speech arguing against the further use of fossil fuels.

Unfortunately, his plea to stop burning carbon in its various forms was lost in a cloud of smoke.

In an appearance on "The Joe Rogan Experience" podcast on Thursday, Musk called the ongoing use of fossil fuels "an insane experiment" and called for humanity to speed up the adoption of sustainable energy sources to replace them.

"We're really playing a crazy game here with the atmosphere and the oceans," Musk said. "We're taking vast amounts of carbon from deep underground and putting this in the atmosphere — this is crazy. We should not do this. It's very dangerous."

However earnest Musk's plea might have been, it was largely ignored afterward. His interview with Joe Rogan has become notorious because during it he smoked pot on camera — a single puff, taken in California where recreational cannabis use is legal under state law. Following Musk's appearance — and the departure of two executives at Tesla on Friday — Tesla's stock plunged 7%.

Musk's marijuana moment overshadowed other important discussions in the interview also. He and Rogan spoke about everything from artificial intelligence to electric planes to the damaging effects of social media. Instead of the interview sparking larger conversations about those topics, Musk's pot smoking during it quickly turned into a meme.

Musk's marijuana use was quite a moment. The Joe Rogan Experience/YouTube

Musk explained why he focuses on cars not airplanes

But the biggest loss in all the focus on Musk's marijuana use was the ignoring of his talk about fossil fuels. During the conversation, he gave an important explanation of why he's concentrated on electric cars, solar energy, and battery technology instead of other things, such as electric planes.

"The electric airplane isn't necessary right now," Musk said. "Electric cars are important. Solar energy is important. Stationary storage of energy is important. These things are much more important than creating electric supersonic [airplanes]. It's important that we accelerate the transition to sustainable energy."

Though Musk clearly stands to profit from the move to electric vehicles with Tesla and solar energy with Solar City, it was clear from his emotional response that the move to sustainable energy is more than just business to him. You could see it in his mannerisms.

In the video, Musk shakes his fist back and forth, repeatedly looking away from Rogan to maintain his composure. He takes long pauses while speaking and looks visibly shaken. His face gets flush.

Notably, all of this took place more than an hour before he smoked any weed.

Musk grew impassioned talking about the necessity of moving away from fossil fuels. The Joe Rogan Podcast/YouTube

Burning fossil fuels is an "insane experiment"

It was only when he dug into the logical underpinnings of fossil-fuel use — or the lack thereof — that he seemed to shake his emotions.

"The bizarre thing is that obviously we're going to run out of oil in the long-term. There's only so much oil we can mine and burn," Musk said. "It's tautological. We must have a sustainable energy transport and infrastructure in the long term, so why run this crazy experiment where we take trillions of tons of carbon from underground and put it in the atmosphere and the oceans? This is an insane experiment. It's the dumbest experiment in human history."

Musk isn't solely focused on sustainable energy. He also runs SpaceX, a rocket company that aims to make space travel far less expensive; The Boring Company, a tunnel digging company that's attempting to dig tunnels underneath Los Angeles for high-speed travel; and Neuralink, a technology company that's trying to create an interface between brains and computers.

"I have a lot on my plate," is how he put it to Rogan.

But it's clear from Musk's emotional response to the issue of human energy consumption that he takes the threat of carbon-induced climate change personally.

Unfortunately, that side didn't come across in all the headlines about pot smoking and stock-price fluctuations.

See the exchange in full here (starting at 1:18:13):