Outdoor Experiments
Make Sunsets
Make Sunsets is a U.S.-based company that launches balloons filled with sulphur dioxide, aiming to cool the climate.
Status
| Status | Ongoing |
| Start/End | 2023 / Ongoing |
| Location | California, USA |
| Type | Stratospheric Aerosol Injection |
| Experiment Type | Non-Scientific |
| Funded By | Boost VC, Draper Associates, Pioneer Fund |
Description
Make Sunsets is a private, US-based company founded in 2022 with the goal of implementing stratospheric aerosol injection (SAI) commercially in an effort to lower global temperatures. Since February 2023, Make Sunsets has delivered more than 140 kg of sulphur dioxide to the stratosphere via the launch of more than 160 balloons. The company claims each gram of sulphur dioxide offsets the warming from approximately 1 tonne of carbon dioxide for a year and sells each gram as a “Cooling Credit” to consumers.
In April 2025, the US Environmental Protection Agency Office of Air and Radiation submitted a demand for information from Make Sunsets, questioning whether the group’s small actions to date have had an impact on air quality. Experts have noted that this demand may have motivations rooted in political agendas rather than air quality concerns.
Funding for Make Sunsets comes from Boost VC, Draper Associates, Pioneer Fund, angel investors, and consumers who purchase cooling credits from their website. As of writing, more than 870 people have purchased these credits despite concerns from scientific and policy experts that cooling credits are not an effective approach to SRM.
Key Papers
Burns, W., & Talati, S. (2024). The Solar Geoengineering Ecosystem: Key Actors Across the Landscape of the Field. https://sgdeliberation.org/publications/updated-solar-geoengineering-ecosystem/