If you listen to this show, you probably already think that we need to slash human emissions to prevent catastrophic climate change. In many ways, our species has been engaged in a massive, uncontrolled geoengineering project that’s heating up the planet to the point where wildlife extinction, massive floods and fires, and other tragedies are now simply routine.

So far, humanity’s geoengineering has largely been limited to heating the earth up. But what about purposeful geoengineering to actually cool the planet down? In other words, while we’re waiting to get our act together on emissions, why not reflect some of the sunshine beaming onto our pale blue dot back into space, so we can shade ourselves and keep cooler in the meantime?

The idea’s been discussed in sci-fi literature for decades, and is even being researched by the federal government right now. (See here, here, and here, for example.) But one serial entrepreneur decided to take the earth’s climate into his own hands and start his own geoengineering company, Make Sunsets.

The idea is simple: When volcanoes erupt, they spew sulfur dioxide into the stratosphere, reflecting a small amount of sunlight back into space, thereby tangibly cooling the planet temporarily. So, figured Make Sunsets CEO Luke Iseman, why not just put the sulfur dioxide in the stratosphere himself?

So Luke bought a balloon on Amazon, filled it with helium to make it rise along with a couple grams of sulfur dioxide as payload, and he let it go. Fast forward a year later, and his launch has been condemned by many around the globe as irresponsibly hubristic, yet also praised by many who see such geoengineering as the best of a list of bad options. If he could do the same thing as the initial launch but orders of magnitude greater, he could meaningfully cool the planet down to prevent some of the worst effects of climate change, at least for a year or two, unless he was continually doing it. 

As Luke says, “Every day that we don’t inject sulfur dioxide into the stratosphere as responsibly as the state of the science will let us and as much as we can economically, species are needlessly going extinct and people are dying.”

So far Make Sunsets is still a tiny startup: two employees with about a million dollars of venture capital raised, though from some of the biggest names in Silicon Valley. They’re already selling cooling credits—think carbon credits, but instead of removing CO2 from the atmosphere they’re just cooling the planet down without actually altering CO2 levels. He’s clear that sulfur dioxide injections into the stratosphere are a means of simply buying ourselves time to get our emissions under control, not a replacement for emissions reduction.

So, see what you think. Is Make Sunsets a planetary savior or an well-intentioned but potentially apocalyptic idea? I really enjoyed talking with Luke and I think you’ll enjoy listening.

Discussed in this episode

• The controversy caused by Make Sunsets has been covered on CNN, NY Times, CNBC, The Guardian, Washington Post, and more.  

• Luke was inspired to start Make Sunsets after reading Termination Shock by Neal Stephenson.

• Paul learned of Make Sunsets via the Wall Street Journal’s podcast.

• Luke’s initial launch caused the Mexican government to act against him.

• Luke recommends How to Blow up a Pipeline by Andreas Malm, The Creative Act by Rick Rubin, and The Artist's Way by Julia Cameron.

• Paul mentions Snowpiercer, a story about a global winter unexpectedly befalling earth after a project similar to Make Sunsets.

• Our past episodes with philosopher Peter Singer and carbon capturer Graciela Chichilninsky. Interestingly, Peter Singer recently endorsed the idea of at least researching geoengineering.

• Luke maintains a list of companies he’d like to build, and one idea in particular he just can’t get out of his head.

More about Luke Iseman

Luke Iseman is cofounder of Make Sunsets, a startup that launches reflective clouds to fight global warming. They have deployed over 3000 ton-years worth of cooling for paying customers, and their mission is to Cool Earth by 1C before 2030. Previously, Luke was founder of several hardware startups and Director of Hardware at Y Combinator.