Who gains from saving nature
Ledger 1 : 33 — For each dollar financing nature-based solutions in 2023, about $33 financed activities harmful to nature. (UNEP)
Cases / Carbon capture and climate intervention · Mexico · 2022–2025

Make Sunsets stratospheric balloon launches (Mexico)

Nature's voice · report
No measurement of the harm done to me here is on record.
Did nature suffer? Not measured.
Not on record
  • The record does not name which of my species, waters, soils or forests were harmed.
What the record lacks: 2 none on record · 1 not disclosed · 2 insufficient · 1 not measured · 2 disputed · 2 unclear See the gaps

A start-up founder launched weather balloons in Baja California in April 2022 without permits and later sold USD 10 "cooling credits" tied to releasing sulphur dioxide in the stratosphere. Mexico announced a ban on such experiments in January 2023.

147 balloons / 128,000 creditsBalloons launched and cooling credits sold, February 2023 to April 2025
Figures from the company's website as reported by Inside Climate News in April 2025. Company revenue was not disclosed.

Status As of the latest sources: Mexico announced a ban in January 2023; the EPA requested information from the company in April 2025; no outcome found.

What?
A start-up launched balloons in Baja California in April 2022 without permits or measuring instruments and later sold cooling credits for releasing sulphur dioxide in the stratosphere.
Where?
Baja California, Mexico (first launches); the US Environmental Protection Agency is the regulator that requested information.
When?
First balloons in April 2022; credit sales and 147 launches from February 2023 to April 2025; Mexican ban announced January 2023.
Who?
Gained
  • Make Sunsets — Sold 128,000 credits at USD 10 per credit between February 2023 and April 2025 according to its website; revenue not disclosed.
  • Investors including Boost VC and Pioneer Fund — Put about USD 750,000 into the company, according to the company.
Lost
None on record
Harmed
None on record
Why?
The company's founder described the venture as part business and part provocation.
How?
Weather balloons release sulphur dioxide; each USD 10 credit corresponds to at least one gram, which the company says offsets the warming of one tonne of carbon dioxide for one year.
6 of 6 questions answered from the record

What happened

The record, in order.

Make Sunsets sells "cooling credits" at USD 10 each. According to Climate Home News (2023), each credit stands for the release of at least one gram of sulphur dioxide in the stratosphere, which the company says offsets the warming effect of one tonne of carbon dioxide for one year.

The company's founder, Luke Iseman, launched the first two balloons in April 2022 in the Mexican state of Baja California, before the company was formed. According to MIT Technology Review (2022), he had no permits and the balloons carried no measuring instruments; whether the particles reached the stratosphere is not known. The company said it had raised about USD 750,000 from investors including Boost VC and Pioneer Fund. Iseman described the venture as part business and part provocation.

Kelly Wanser, an executive at the organisation SilverLining, described the credits as speculative and of no value (MIT Technology Review, 2022). According to the company's website in April 2025, 147 balloons had been launched and 128,000 credits sold since February 2023. The company has not disclosed its revenue.

In January 2023 the Mexican government announced that it would ban solar geoengineering experiments, stating that the balloons had been launched without prior notice and without the consent of the Mexican government or the surrounding communities (Climate Home News, 2023). In April 2025 the US Environmental Protection Agency asked Make Sunsets for information; the outcome is not on record.

Other outdoor experiments met resistance elsewhere. Harvard's SCoPEx balloon experiment, planned for 2021 from Kiruna in Sweden, was cancelled after the Saami Council wrote that there was no acceptable reason to allow the project in Sweden or elsewhere and after its advisory committee decided against the flight; the project was abandoned in March 2024 (MIT Technology Review, 2024). The city of Alameda, California, voted unanimously 5-0 in June 2024 to stop a University of Washington cloud-brightening experiment that researchers had begun without permission (NBC, 2024); more than 70 environmental groups had objected.

  1. 2022April: first two balloons launched in Baja California without permits or measuring instruments; January 2022: more than 60 academics call for an International Non-Use Agreement on solar geoengineering
  2. 2023January: Mexico announces a ban on solar geoengineering experiments. February: Make Sunsets' recorded 147-balloon, 128,000-credit sales period begins; Africa's environment ministers' conference (AMCEN) calls for a non-use mechanism
  3. 2024March: SCoPEx abandoned. June: Alameda stops a cloud-brightening experiment
  4. 2025April: EPA asks Make Sunsets for information; company website reports 147 balloons and 128,000 credits sold since February 2023. May: UK agency ARIA funds 21 projects, five with outdoor experiments. July: AMCEN, meeting in Nairobi, calls explicitly for a non-use agreement. October: Stardust Solutions announces a USD 60 million round

What was said

Claims, in the words of those who made them.

Where accounts differ

Each party's account, side by side, with its source. The record does not settle these points; it shows them.

Does one gram of sulphur dioxide released by a balloon offset the warming of one tonne of carbon dioxide for a year?
Company or project
Make Sunsets

Sells each USD 10 credit as releasing at least one gram of sulphur dioxide in the stratosphere, offsetting the warming effect of one tonne of carbon dioxide for one year.

Communities and civil society
SilverLining (executive Kelly Wanser)

Described the credits as speculative and of no value.

Researchers
Scientists cited by MIT Technology Review (2022)

Found the credits speculative.

Is outdoor solar geoengineering experimentation acceptable without prior notice and public consent?
Government and regulators
Government of Mexico

Said the balloons were launched without prior notice and without the consent of the Mexican government or surrounding communities; announced a ban in January 2023.

Communities and civil society
Saami Council

Wrote that there was no acceptable reason to allow SCoPEx in Sweden or elsewhere.

Researchers
More than 60 academics (January 2022)

Called for an International Non-Use Agreement with five principles: no public funding, a ban on outdoor experiments, no patents, no use of technologies developed by third parties, and opposition to institutionalising solar geoengineering as a policy option in international bodies. Their letter names "moral hazard": hope of future geoengineering could weaken emission-cut commitments.

International bodies
African Ministerial Conference on the Environment (AMCEN)

Called for a non-use governance mechanism in 2023 and explicitly for a non-use agreement in Nairobi in July 2025; about sixty Global South countries made a similar call.

Government and regulators
UK agency ARIA

In May 2025 awarded about USD 60 million to 21 projects, five of them with outdoor experiments (Scientific American, 2025).

How it looked

What was shown, beside what was recorded.

Shown

  • A USD 10 credit that releases at least one gram of sulphur dioxide in the stratosphere and offsets the warming effect of one tonne of carbon dioxide for one year
    Make Sunsets, as reported by Climate Home News (2023)

Recorded

  • The first two balloons, launched in April 2022 in Baja California, had no permits and carried no measuring instruments; whether the particles reached the stratosphere is not known
  • Mexico announced in January 2023 that it would ban such experiments
  • 147 balloons launched and 128,000 credits sold between February 2023 and April 2025, according to the company's website
  • The company has not disclosed its revenue

Who gained

Money that reached nature, beside money that stayed elsewhere.

Reached nature or the ground

Not published
No figure published.

Gained elsewhere

Not totalled
Currency: USD · Window: 2022-2025. All figures cover the same period. * Estimate built from cited figures.

Responses on record

  • make-sunsets (2022): The founder described the venture as part business and part provocation (MIT Technology Review, 2022).
  • mexico-gov (January 2023): Said the balloons were launched without prior notice and without the consent of the Mexican government or surrounding communities, and announced it would ban the experiments.

In court and with insurers

Every proceeding and every insurer decision on record.

Lawsuits and rulings

  1. 2025-04–Outcome not on record
    EPA request for information to Make Sunsets
    US Environmental Protection Agency · Regulatory · US Environmental Protection Agency → Make Sunsets

    The EPA requested information from Make Sunsets in April 2025. The outcome is not known.

Insurers

No insurer decision on record.

What nature saw

Outcomes measured on the ground, and nature's note.

Nature's report opens this page. Below: further outcomes measured on the ground.

Particles reached the stratosphere
Not known
The first two balloons carried no measuring instruments
Permits for the first launch
None
April 2022, Baja California (MIT Technology Review, 2022)
Independent evaluation of the credit claim
None found
The credits were described as speculative by SilverLining's executive and by scientists cited by MIT Technology Review

What we don't know

Undisclosed, unproven, untried: recorded as data.
No independent ecological evaluationKey earnings undisclosed

Nature

  • Not measured Harm to nature: No independent ecological evaluation is on record.

Court

  • Unclear EPA request for information to Make Sunsets: outcome not on record.

Accounts

  • Disputed Does one gram of sulphur dioxide released by a balloon offset the warming of one tonne of carbon dioxide for a year?
  • Disputed Is outdoor solar geoengineering experimentation acceptable without prior notice and public consent?

Record

  • Unclear Whether the particles released in April 2022 reached the stratosphere: not known.
  • Not disclosed Make Sunsets' revenue: not disclosed.
  • None on record Outcome of the EPA's April 2025 request for information to Make Sunsets: not known.
  • None on record Where the launches after February 2023 took place: the sources reviewed do not say.
  • Insufficient Reported but not independently verified: that Tennessee (2024) and Montana and Florida (2025) banned solar geoengineering, and that some such state laws draw on the "chemtrail" conspiracy belief.
  • Insufficient Reported but not independently verified: that Boost VC is the fund of Adam Draper.

Did the harm stop?

Mexico announced a ban on such experiments in January 2023. According to the company's website, 147 balloons were launched between February 2023 and April 2025; the sources reviewed do not give their launch locations.

Who paid?

Buyers paid USD 10 per credit. The company said it had raised about USD 750,000 from investors. Company revenue was not disclosed.

Sources

Voices on record: — Company or project— Government and regulators— Courts— Press and investigations— Communities and civil society— Researchers

Connected cases

Related matters, and cases linked to this one through the same organisations, with the role each played in both.
Terms used on this page

Institutions

EPA
The US Environmental Protection Agency.

Carbon and conservation finance

Carbon credit
A certificate representing one tonne of carbon dioxide (or equivalent) that a project says it reduced, avoided or removed. Buyers use credits to balance their own emissions in climate claims.
Offset
Using carbon credits to balance emissions released elsewhere, so that a buyer can claim lower or zero net emissions.

Science and environment

PFOA (C8) and PFAS
PFAS are a large family of human-made chemicals that persist in the environment and the body; PFOA, also called C8, is one of them and was used to make Teflon.
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