We launch reflective clouds into the stratosphere.

Unless we reflect sunlight (albedo enhancement), 10s of millions of people will die and 20%+ of species may go extinct. We're using the most effective way to reflect sunlight that we've found and can afford to deploy (<$50k startup cost). 

We release the same particle as volcanoes have for millennia. Most famous example: Mount Pinatubo. This one eruption cooled earth by .6C for a year! Further proof came from changes in maritime emissions.

2-3 years.

Shorthand is that "a gram offsets a ton:" one gram of sulfur delivered to 20km altitude creates as much radiative forcing as one ton of CO₂ released in the atmosphere does in a year. There's a lot of uncertainty and assumptions here (including a 3x difference among IPCC scientists on global warming per unit CO₂ ). As we perform more releases, we'll learn a lot more about our efficacy. However, uncertainty isn't an excuse for inaction.

They are not water vapor, so in a technical sense no. In a "cloud of dust" sense, they are ;)

Yes. In the United States, our method to cool Earth falls under the Weather Modification Act. As required, we report yearly to NOAA.

Any human-caused release of carbon dioxide is geoengineering: the earth is a bit warmer for every breath you take. We think it's wrong to suddenly draw a line at the stratosphere: we screwed up the atmosphere, and now we have a moral obligation to fix things!

These are great, but they are far from enough. Even if we magically stopped all carbon emissions right now, we'd still likely hit 2.3C! Given that greenhouse gas emissions increase ~every year, we need to start cooling the world immediately.

And we would like an equitable future with breathable air and no wet bulb events for generations to come. Convince us there's a more feasible way to buy us the time to get there and we'll stop. We'll happily debate anyone on this, just confirm an audience of at least 100 people and we'll find the time to try and convince you 😉

We have. 😉 Several academic attempts were canceled due to well-intentioned but misguided activism and patent disputes.

Maybe! We have no religion about how we produce the cooling we need and want the most cooling per $ we can safely + quickly achieve. Personally, we lack the $B+ startup costs (and substantial political capital) for these other methods. If you or your government are credibly attempting to build one of these, we'd be happy to collaborate

We fly instrumentation to verify latitude, longitude, and altitude of deployment. If a launch doesn't reach 20km, the Cooling Credits do not count and we redeploy. When we scale to 1M+ Cooling Credits per month, we'll measure and learn more.

We can create sufficient cooling to offset this year's new warming for ~$30M per year: $7M of sulfur + deployment costs.

~$100B per year to drop global temperatures by .5C. This doesn't offset all man-made warming, but it does get global temperatures out of the insane range.

No: it's likely much worse. We're very unlikely to stop mining proven petroleum reserves, and even the worst-case IPCC projections of 4C by the year 2100 don't include any massive natural releases of greenhouse gases (tundra methane, etc.). We need to act now to Cool Earth!

Modeling shows a slight but meaningful depletion in ozone. While we'll closely monitor this, it's important to note that worst-case scenarios for ozone depletion amount to 5-10% on average. This is less than half of what CFCs caused and may be at least partially offset by reduced global warming's positive impact on ozone.

Location matters: we're too high and diffuse to create a meaningful amount of acid rain. "If SAI were used to keep temperatures at 2020 levels under this scenario, offsetting more than 2°C of warming, global sulphate deposition would only fall by roughly 40%."

None: we're only addressing the warming impact of greenhouse gas emissions.

Preliminary modeling actually shows the opposite: a ~10% net increase.

100:1, conservatively.

Because we're aiming for 70% margins;) It costs us ~$0.28 per Cooling Credit successfully deployed. You can see a breakdown of our costs here.

As of April 2026, we have successfully deployed Cooling Credits for over 1,070 individuals. You can see quotes from some of them in our first zine (pdf).

We used helium at first because we were nervous about Hindenburg 2.0s. Having better educated ourselves, we now use hydrogen for the vast majority of our deployments.

We follow Y Combinator's mantra: Make Something People Want. We've made this, and now we need to prove people want it. The most helpful way to get involved is to buy now.

Introductions to companies that want to purchase larger quantities of Cooling Credits and/or countries interested in hosting balloon launch sites would both be very helpful.

Our balloons are latex, not plastic. They biodegrade within 3 years.