Yesterday, we launched 3 biodegradable latex balloons to the stratosphere and released reflective sulfur aerosols to cool the Earth. Together, they offset the warming of ~5,855 tons of CO₂ for one year (equivalent to the annual emissions of 1,272 cars). Watch the launches ↓ 1 of 3 Balloons Launch Date: Oct. 30th, 2025 Balloon Weight: 1,515 grams SO₂ Payload: 1,985 grams Injection Altitude: 27,259 meters Delivery: Kaymont HAB-TX-1500 weather balloon

It’s the dose that makes the poison. In the past two years, I’ve sent 238 pounds of sulfur dioxide into the stratosphere—enough to offset the same amount of warming as 5.16 million trees would remove for a year. That’s a 1 to 1,000,000 leverage.

Earlier this week, we deployed ~12.99 pounds of sulfur dioxide (SO₂) into the stratosphere, including one launch that reached an altitude of 101,400 feet. These deployments offset the warming effect of 5,895 metric tons of CO₂ for a year. In under three hours, we achieved the climate-cooling equivalent of planting 267,954 mature trees. 🧵1/2

We delivered 4,125 ton-years of cooling today with three balloons which is the equivalent of planting 196,428 trees that last for a year.

Yesterday, 7 more balloons carrying ~22 pounds of sulfur dioxide were launched, and 6 made it to the stratosphere to cool Earth. This is the cooling equivalent of 476,190 mature trees that last for a year. Thank you to our awesome customers who made it happen.

The OG delivery vehicle for stratospheric aerosol injection just popped off today. 🌋 #RuangVolcano has erupted, sending SO2 into the stratosphere, mimicking what geoengineers propose with aerosol injections! 🌍💨 This natural event offers a real-time glimpse into how #GeoEngineering could cool our planet by reflecting sunlight away. Could this be a window into a sustainable solution for climate change? 🤔 Learn more about how these natural laboratories are guiding our approach to #ClimateAction. 👇 makesunsets.com/pages/what #Volcanology #ClimateChange #CoolEarth

Big thanks to all the people who came out today to help us cool Earth. This was the third balloon with a payload 1,030 grams of SO2. It's still traveling to the stratosphere and if reached will be the equivalent of planting 49,047 trees that last for a year.

Stratospheric aerosol injected

Yesterday, we deployed seven biodegradable natural latex balloons with measured sulfur dioxide and hydrogen. All reached the stratosphere. Telemetry confirmed 10,525 Cooling Credits reached 20km+, offsetting 10,525 metric tons of carbon dioxide warming for a year. This is the equivalent of 478,409 mature trees that last for a year done in 2 hours. Here is a thread on all seven launches with details: 1st of 7 Balloons Launch Date: July 23, 2025 Balloon Weight: 1,515 grams SO2 Payload: 1,385 grams Injection Altitude: 23,755 meters Delivery: Kaymont HAB-TX-1500 weather balloon

Make Earth Cool Again. Yesterday, we had special guests @gwern and @LittleZeitgeist help us deploy reflective clouds next to the Ozone layer to cool Earth. In total we launched four balloons and placed ~7.25 pounds of sulfur dioxide (SO₂) close to the Ozone layer, including one launch that reached a height of 101,358 feet. These deployments offset the warming effect of 3,290 metric tons of CO₂ for a year. We achieved the climate-cooling equivalent of planting 149,545 mature trees that last for a year.

Great, go to the tropics.

Picture this: A single dollar bill's weight and cost in SO2 deployed in the stratosphere can offset the heat of a ton of CO2 for an entire year. This strikingly affordable and straightforward remedy is your chance to make a significant, hands-on impact in the fight against global warming. #climatedads let's turn down the thermostat. Here's how: buy.stripe.com/4gw14BfV3elc8… or if you're not ready to commit, here is the one-off price: makesunsets.com/pages/buy-cl…

ngl, pretty wild that this company is VC backed and people are paying us to deploy SO2 into the stratosphere. Y'all are wild.

And we'll use the Elon bucks to send more SO2 into the stratosphere to cool Earth! Thanks for interacting with this post!

We're a two-person startup, and proud that the EPA is paying attention. Stratospheric aerosol injection has incredible leverage: just 1 ton of SO₂ in the stratosphere offsets 1 million tons of CO₂ warming for a year. That deserves scrutiny and support. Let's scale this solution responsibly.

Saving Private Earth

🚨🌎 Here’s a thought: instead of climate scientists sounding the alarm about the 1.5°C tipping point target again and again and again… maybe we should do something about it? #climateaction #science

If you want to understand how safe it is from a quantifiable amount, this table, generated by an LLM, gives you an idea of what we can safely deploy AND cool Earth based on academic papers: consensus.app/search/stratos…

We’re trying to dim ~1 % of the sunlight hitting Earth—and we publish the play-by-play. Every month we drop a candid blog post with the exact same numbers and milestones our investors see. Whether you’re a customer, critic, or just SAI-curious, dive into the latest chapter below.

Yesterday we sent a biodegradable balloon to 92,706 ft with 2,260 g of SO₂ and hydrogen lift. Same physics that cooled Earth after Mt. Pinatubo in 1991, now done on purpose. This one flight ≈ 2,260 tCO₂-year cooled or ~102,727 mature trees that last a year. Want us to scale this? Join here makesunsets.com/products/joi…

2 of 3 Balloons Launch Date: Oct. 30th, 2025 Balloon Weight: 1,515 grams SO₂ Payload: 2,135 grams Injection Altitude: 30,846 meters Delivery: Kaymont HAB-TX-1500 weather balloon

lol. muting you now.

Yes, very cool. No sulfur rain. We deploy above the rain clouds. Here's a video.

Two balloons were launched today in California. Both balloons reached the stratosphere and offset the warming of 2,820 tons of CO2 for a year. This is the equivalent of 134,285 mature trees that last for a year. 1st Balloon: 1,710 Cooling Credits deployed at 35,060 meters 2nd Balloon: 1,110 Cooling Credits deployed at 36,570 meters Screenshot of the flight path below. cc: @dgelles

3 of 3 Balloons Launch Date: Oct. 30th, 2025 Balloon Weight: 1,515 grams SO₂ Payload: 1,735 grams Injection Altitude: 30,251 meters Delivery: Kaymont HAB-TX-1500 weather balloon

Last Friday, we launched 1.6kg of sulfur dioxide into the stratosphere and reached an altitude of 30,358 meters. This one balloon offsets the warming effect of 1,600 tons of carbon dioxide for a year.

They asked us questions and we answered back in May cdn.shopify.com/s/files/1/06…

Thanks for watching. If you like what you see, help us cool Earth makesunsets.com/products/joi…

Front page of @USATODAY

Thank you @powerbottomdad1! In honor of your support to help cool Earth and being awesome, we've discounted Cooling Credits till 4/20 using the code: 'PBD'

Just add SO2, lift gas and put it in the stratosphere and you get the cooling effect of 190,472 trees that last for a year.

On Earth Day 2025, we deployed four natural latex biodegradable weather balloons with a total payload of 7,200 grams (~15.8 pounds) of sulfur dioxide into the stratosphere. These 4🎈 offset the warming effect of 7,200 metric tons of CO2 for a year. Or another way to put it, we offset the warming effect of 1,565 gas-powered cars for a year. Thanks to all our customers who helped us make Earth a little cooler.

Given that leverage, you might think people would see sulfur dioxide as a powerful solution. Instead, the focus often falls on whether any amount of SO₂ will trigger acid rain or dangerous side effects. But there’s a crucial detail most critics overlook: concentration and location matter. A small dose of SO₂, carefully placed in the upper atmosphere, is radically different from the same dose emitted at ground level.

We make reflective clouds in the stratosphere to address global warming, and can do it for you too! One cooling credit cools Earth by a ton of CO₂’s warming for a year Our subscribers pay a dollar per credit

Not a lot if you do it right. Read more here: unchartedterritories.tomaspu…

Yup, sounds weird but some gases trap heat (CO2) in the atmosphere and others reflect it away (SO2) Here's a write up if you want to learn more: cremieux.xyz/p/from-pollutio… TL;DR we've been accidently cooling the planet, we've just been doing it the worst way possible.

We're excited to work with the EPA to ensure American energy dominance as well as a healthy environment by Making Earth Cool Again (link below)

We use hydrogen.

We're not hiring, but the next best thing to cooling Earth is to work with Casey.

Kinda wild that 25+ people took time out of their day to watch us inflate weather balloons filled with sulfur dioxide (SO2) and helium, then hand off to kids and one kid at heart to release SO2 into the stratosphere to cool Earth. Y'all are a fun bunch. Thank you.

Last balloon of the day. This had our largest payload of the day with 4.32 pounds of sulfur dioxide in the biodegradable natural latex balloon. Thanks to all our customers who helped us cool Earth. Here's how you can directly help: makesunsets.com/products/joi… 2/2

On 12/2/24, 3 x🎈's with 4,845 grams of SO₂ made it to the stratosphere. This offsets the warming effect of 4,845 tons of CO₂ for a year. This is the equivalent cooling effect of 230,714 🌳's or offset warming caused by emissions from about 1,053 🇺🇸⛽️🚗 for a year.

Nobody will remember: - your salary - how “busy” you were - how many hours you worked People will remember: - how much SO2 you put into the stratosphere to cool Earth

Yesterday, we deployed three balloons with a total payload of 6,075 grams of sulfur dioxide (SO2) into the stratosphere, decoupling the warming of 6,075 tons of CO2 for a year. 🌍 🌳That’s like planting 289,285 trees that last for a year! 🌳 Bonus: We made history with the first-ever balloon launch carrying the largest SO2 payload into the stratosphere—3,095 grams in a single 4kg balloon! Special thanks to @nickvanosdol and @thomaskeliot for documenting the launch and helping us cool Earth.

🌅🧴🌍Imagine using sunscreen for the planet to combat climate change! With emerging geoengineering solutions like Stratospheric Aerosol Injection, we can cool Earth temporarily until humanity can transition off fossil fuels and scale up carbon removal. How interested would you be in paying for such a service? Share your thoughts on why you picked your choice! #ClimateActionNow #ClimateChange #Geoengineering #Environment #Sustainability #StratosphericAerosolInjection #PlanetarySunscreen

A lot.

No, it's too low and harms humans; we deploy it next to the Ozone layer. These balloons went above 66,000 feet. Learn more here cremieux.xyz/p/from-pollutio…

How it started: 12/24/22 How it's going: 10/1/23 2024 is gonna be wild.

Last Friday, we launched three balloons. The first one was testing our return-to-home payload to make it easier to recover from the field. 🎈🧵👇

Love this question—and it’s exactly why some folks get confused and say we should “just vent SO₂ from power plants.” They’re mixing up the troposphere and the stratosphere. Letting SO₂ slip past smokestack scrubbers would cool a bit locally, but it also drives acid rain, haze, and respiratory disease. In places/times where SO₂ controls have been weak (e.g., parts of India and China), that’s effectively what happens—and the health and environmental costs are huge. nitter.app/ASong408/status/193571… We go higher—into the stratosphere—on purpose. That’s where the ozone layer resides and where the Brewer–Dobson circulation slowly spreads particles around the globe. Ozone is produced mostly in the tropical stratosphere when UV splits O₂ and it recombines into O₃; then air motions transport ozone poleward, which is why satellite maps show a global “ozone layer.” If you release SO₂ in the troposphere, it’s washed out in days to ~10 days. In the stratosphere, it converts to sulfate aerosols that persist ~1–2 years, giving a cooler, steadier, global effect. In short: stratospheric delivery = fewer injections, longer life, and worldwide distribution—without the smog and acid rain you get from tropospheric emissions. It’s our “Ozempic for climate,” the same basic cooling mechanism big stratovolcanoes demonstrate in nature—just measured, higher up, and far cleaner for people on the ground.

Make Earth Cool Again. Yesterday we launched 8 biodegradable weather balloons, 6 reached the stratosphere (20km+). Together, they offset the warming of 9,415 tons of CO₂ for a year, the same as 427,954 mature trees that last for a year. 🌳 Huge thanks to our customers for helping us cool Earth. Launch details below: 1 of 8 Balloons Launch Date: Sept 9th, 2025 Balloon Weight: 1,495 grams SO2 Payload: 1,305 grams Injection Altitude: 31,386 meters

Last Friday, we cooled the planet. We launched 10 biodegradable latex balloons carrying measured amounts of sulfur dioxide and hydrogen. 🎈 9 confirmed hits (20km+), 1 likely reached altitude but tracker cut out. Telemetry confirmed 14,010 Cooling Credits neutralizing the warming of 14,010 tonnes of CO₂ for a year. That’s the cooling power of 636,818 mature trees lasting a year. Full launch-by-launch breakdown in the thread ⬇️ 1st of 10 Balloons Launch Date: August 8th, 2025 Balloon Weight: 1,485 grams SO2 Payload: 1,565 grams Injection Altitude: Last reading 5,296 meters Delivery: Kaymont HAB-TX-1500 weather balloon Note: Telemetry likely failed

You don’t have to be a chemist to understand why. The same chemical can have very different impacts at different altitudes, concentrations, and contexts. And yet, we rarely apply the same logical lens when it comes to intentional stratospheric aerosol injection (SAI). We hear “SO₂” and suddenly assume the worst, forgetting that people are already burning tens of millions of tons of sulfur each year at ground level with all sorts of known health impacts.

Last Friday, 2 more balloons with sulfur dioxide and hydrogen reached the stratosphere (20km+). That brings us to 207 launches since 2022, offsetting the warming of 3,310 tons of CO₂ for a year — the same as ~719 cars off the road for a year. Details in the replies.

Thank you @nic_carter. If people want to understand the physics, here is how 2000 Cooling Credits offsets the warming effect of 2,000 tons of CO2 for a year makesunsets.com/blogs/news/c…

This week, we launched 3 biodegradable natural latex balloons to the stratosphere and released reflective sulfur aerosols to cool the Earth. Together, they offset the warming of ~4,315 tons of CO₂ for one year (≈ ~938 cars/yr). Watch the timelapse ↓ Engage & win Cooling Credits Moon hunt: spot the Moon in the video and reply with a screenshot — first one wins. Best frame: post your favorite still; most likes by Mon. 11/10, 5pm PT wins. Winners get enough Cooling Credits to offset their carbon footprint for a year. 1 of 3 — Halloween launch • Date: Oct 31, 2025 • Balloon mass: 1,515 g • SO₂ payload: 785 g • Injection altitude: 22,326 m • Platform: Kaymont HAB-TX-1500

Last Friday, we launched 5 balloons and confirmed that 4 reached the stratosphere. In total, 13.76 pounds of sulfur dioxide was sent up. This is equivalent to 297,142 🌲 that last for a year or offsetting the warming effect of 6,240 tons of CO2 for a year!

I get that the notion of “injecting particles into the sky” raises eyebrows. It’s natural to worry about “messing with nature,” but I ask: where’s the conversation around all the other ways we’re messing with nature—often in far more harmful ways, at ground level, with little to no control?

We had the youngest person (7 years old) ever to cool Earth by stratospheric aerosol injection this week. She deployed 680 Cooling Credits, equivalent to planting 32,380 trees that last for a year.

So let’s start with the facts: Quantity: 238 pounds in total, over two years, distributed high in the stratosphere. Impact: Offsets the warming equivalent of a forest of 5.16 million trees for one year. Trade-off: If you compare deploying a controlled, measured dose in the stratosphere to the benefits gained, it’s a clear win—when done responsibly.

1/ We launched two drones today to test autonomous return-to-home… and both succeeded! ✅ Here’s Video 1: A drone reaching ~41,322 ft, separating from a balloon, and beginning its 18-mile journey back. 📹👇 🧵⬇️ More videos in the thread

Three more balloons reached the stratosphere to offset the warming caused by 4,020 tons of CO2 for a year. This is the equivalent of masking the warming caused by 873 US gas-powered cars for a year. Or the equivalent cooling of 191,428 trees that last for a year. Note: @CBC was there to document the first two launches.

From 10/20/24 to 10/24/24 we deployed 4 x🎈 carrying 6,115 grams of sulfur dioxide into the stratosphere. This is the equivalent cooling effect of 291,190 trees that last for a year. We were not able to capture video of the 1st video, but we had over 100 people witness the launch at @makerfaire. For the 2nd and 3rd deployments, @tomaspueyo helped and the last one was done by us.

Not a moonshot. Sunscreen for Earth.

These balloons are too small, but if people show more interest, we can scale up to 1-ton payloads of SO2 per balloon.

Ozempic for climate change.

What makes you think we'll stick with these smaller balloons? NASA has balloons that can carry over 1 metric ton of payload. Also, 1.2 million balloons are not a lot. ATL Airport has ~800k takeoffs and landings per year. Sure, it's the busiest airport in the world, but it's just one airport. We could have multiple launch sites and not have to worry about metal tubes filled with humans in them flying close to the speed of sound.

We launched 5 more balloons this month to fulfill our customers' orders, delivering ~16.8 pounds of SO2 to the stratosphere. This is equivalent to 363,095 🌲 that last for a year! Here's the 1st one of the day. 🎈🧵1

Yes, we did. Here's a write-up on the difference of application: cremieux.xyz/p/from-pollutio…

We had a five-year-old* princess 👸 deliver 890 ton-years of cooling into the stratosphere (100,755 feet) for a year on 9/14/24. This was the first of three balloons. The SO2 delivered into the stratosphere is equivalent to the cooling effect of 42,380 trees that last for a year. *youngest person to cool Earth via stratospheric aerosol injection

No, an LLM gathered academic papers and quantified the amounts needed for the side effects people are concerned about vs. the proposed amount to cool Earth by 0.5°C for over 20 years.

The US Government would totally buy that, the radar signature of balloons is pretty tough to detect. The Chinese balloons you might have read in the news were able to get deep into US territory before the F-22s shot them down. They were the size of stadiums. Currently, our biggest balloons are 15-20 feet in diameter. You shouldn't be wasting your anti-balloon rocket drones on us, sell to the US and S. Korean government.

Can you point out what the computer made up, please? Thanks! cc: @ConsensusNLP

Last week, we deployed two biodegradable natural latex balloons filled with sulfur dioxide and hydrogen gas to cool the Earth, with the help of one of our customers, the CTO of a lithium extraction technology company for any brine source. Both balloons went over 30 km (18.64 miles) into the stratosphere before releasing the reflective clouds. These two balloons offset the warming effect of 2,820 tons of carbon dioxide for a year. Details and video of the two launches below. 1 of 2 Balloons Launch Date: Oct. 24th, 2025 Balloon Weight: 1,515 grams SO₂ Payload: 1,835 grams Injection Altitude: 30,704 meters Delivery: Kaymont HAB-TX-1500 weather balloon

On 11/27/24, four 🎈's with 5,605 grams of SO2 made it to the stratosphere. This offset the warming effect of 5,605 tons of CO2 for a year. This is the equivalent cooling effect of 266,904 🌲's that lasts a year.

Skills issue.

Climate tech "leaders," reality check time. Your ESG budgets are vanishing, Trump is gutting IRA, cheap offsets are a joke, and expensive ones won’t scale in time. Meanwhile, emissions keep rising and we've sustained 1.5C for over a year. You failed. Instead of clinging to a broken strategy, maybe try something that actually works—cheap, natural, and scalable cooling. 🌍⬇️ Read this, then ask yourself: Are you here to signal, or are you here to fix the planet? unchartedterritories.tomaspu…

All three made it into the stratosphere and we got LoRa working.

In Feb, we deployed ~35.8 pounds of SO2 into the stratosphere, the equivalent to 773,333 mature trees lasting a year. It was our second-largest deployment in a month. To help us cool Earth on a bigger scale, visit makesunsets.com/products/joi… Thanks for watching!

This month marks the two year anniversary of the first commercially deployed stratospheric aerosol injection on US soil, @TIME covered the story.

Zeke we should chat, as you know our deployment sizes are insignificant from a geophysical impact, but, more people know about stratospheric aerosol injection than they did 18 months ago because of us building in the open and talking to the press, warts, and all. We would love to work with Stripe Frontier to push the research with larger field deployments and share that data with scientists to improve their climate models with real in situ data. So far 560 people have paid us to do this, 90% are what I call "climate dads" like yourself. $1 million to launch a 1,000 kg balloon into the stratosphere with SO2 and we will set up a fiscal sponsor that is a 5031c, you can pick the scientists and we'll build the tech to deploy and will not take any profits. This is our pathway to scale and you can help push the frontier. If this doesn't make sense, what does?

So, does this mean we should ignore risks altogether? Absolutely not. We need to scale up deployment carefully and get more data on stratospheric dynamics, long-term climate modeling, and decide if people want this. But the knee-jerk “SO₂ = acid rain” fear isn’t the whole story. Context (dosage, altitude, method of release) is everything.

The balloon released only a few grams of SO2, but the act was a brazen demonstration of something long considered taboo—injecting gases into the stratosphere to try to slow global warming. Once released, SO2 reacts with water vapor to form droplets that become suspended in the air—a type of aerosol—and act as tiny mirrors, reflecting incoming sunlight back to space. Luke Iseman and Andrew Song, founders of solar geoengineering company Make Sunsets, had sold “cooling credits” to companies and individuals; a $10 purchase would fund the release of a gram of SO2, which they said would offset the warming effects of a metric ton of atmospheric carbon dioxide for a year. scientificamerican.com/artic…

Two days before the launch, we got this VM from the @FBI on Friday afternoon. We did it anyway and called them back on Monday.

Last Friday, we deployed 5 biodegradable natural latex balloons with measured amounts of sulfur dioxide and hydrogen. 2 of the balloons might have reached the stratosphere, but could not be verified by telemetry, one balloon lost power around 57,734 ft (17,597m) and the other the is unknown and last altitude transmitted was at 61,473 ft (18,737m). In total, 4,636 Cooling Credits were confirmed by telemetry to reach the stratosphere (20km+), which offsets the warming effect of 4,636 metric tons of carbon dioxide for a year. Here is a thread on all 5 launches and more details about each launch. 1st of 5 Baloons Launch Date: July 11th, 2025 Weight of balloon: 1,500 grams SO2 payload: 1,605 grams Delivery method: Kaymont HAB-TX-1500 weather balloon Notes: could not confirm via telemetry due to power loss and did not reach target altitude of 20,000 meters. Last reading was at 57,734 ft (17,597m).

We reached the stratosphere!

Happy New Year! First balloon launches of 2025. We had a special guest, Nick from @freethinkmedia, aka Hard Reset, who helped us launch balloons filled with SO2 and Hydrogen. Follow them for the upcoming video. We launched 3 balloons that day. Here's the 1st 🎈🧵

Here's how to keep track! makesunsets.com/blogs/news

Made history today.

3rd 🎈

In short: SAI is about putting carefully measured amounts of sulfur dioxide into the stratosphere, not spewing random clouds of SO₂ into the air. If we’re serious about stopping climate change, we need all the cards on the table—including, yes, a bit of sulfur dioxide in the right place.

Great question! Plenty of people are doing that, but it doesn't seem to be happening fast enough, we need to be planting a trillion trees yesterday. I noticed that you're associated with @NicoleShanahan and she recently had @WriterPaulBond on a podcast. He recently wrote about us too, take a look, we'd love to share what we're working on on your podcast. Lots of misinformation and Paul did a great job tackling this topic justthenews.com/politics-pol…

Okay, now do CO2.

It was a half-good idea, they should have shifted the emissions higher, though makesunsets.com/blogs/news/m…

Or hear me out, we can do both. Planting 49,000 trees takes a while. This took less than 20 minutes to deploy and another 3 hours to get to the stratosphere. @yishan is heading up the tree planting, we'll give the world some sunscreen so we reduce the forests from burning and they can achieve their tree planting goals. I hear you on the acid rain. I live on the same planet as you, here is an article @ASong408 wrote that addresses these concerns cremieux.xyz/p/from-pollutio…

The same reason why you wear a welding mask when welding.

🚨 Stratospheric Aerosol Injection: The Emergency Climate Solution We Can’t Ignore 🚨 2024 was the first full year above 1.5°C warming. Stratospheric aerosol injection (SAI) is no longer optional—it’s an urgent necessity to slow climate collapse.

LFG.