Elon Musk says 'do not worry too much' about methane, the gas used in SpaceX rocket fuel that accounts for 20% of global greenhouse emissions

• Elon Musk once again voiced his support for a carbon tax at Tesla's annual shareholder meeting.
• He said the policy "is really needed," and would benefit Tesla, but hurt ultimately SpaceX.

Elon Musk endorsed a carbon tax at Tesla's annual shareholder meeting on Thursday, a position he's held since 2015, even though implementing one could impact his spaceflight ambitions.

Earlier this year, Musk said he suggested the policy to the Biden administration but was told it was too "politically difficult."

"Can there be a carbon tax? I mean, what the hell?" Musk told shareholders, adding that while the tax would benefit Tesla, it would ultimately hurt SpaceX.

He added that people should not "worry too much about methane," the gas responsible for 20% of global greenhouse emissions. According to the EPA, methane is 25 times as strong as carbon dioxide when it comes to trapping heat in the atmosphere.

It's also the gas used to fuel SpaceX's Starship rocket, which Musk hopes to send to Mars. In January, Tesla announced plans to drill near a Texas launchpad for natural gas.

"Methane quickly breaks down into CO2," Musk said. "Methane is not a stable molecule, CO2 is extremely stable."

Significantly reducing methane emissions would "have a rapid and significant effect on atmospheric warming potential," the EPA says. According to the agency's Global Methane Initiative, methane concentrations in the atmosphere have doubled over the last two centuries.

Since SpaceX is among the first companies to use liquid methane and hydrogen as fuel, there is not enough research available to calculate exactly how methane-fueled rocket engines may contribute to greenhouse gas emissions, according to a 2019 report by The Center for Space Policy and Strategy.

With Musk's $100 million investment in carbon-capturing technologies, it may be possible for SpaceX to continuously recycle gas released by its rockets into the atmosphere.

"We try very hard to do the right thing in all respects. We do not always succeed," Musk said at the meeting. "But if you're looking for a company where we say, is that company really trying to do the right thing? That is Tesla."