What the business is
Startup that releases weather balloons carrying sulfur dioxide to reflect sunlight; its founder is a former Y Combinator hardware director.
The bet
That releasing sulfur dioxide from small balloons would reflect sunlight and cool the Earth faster than research was moving.
Starting capital
BoostVC invested $500,000 (per CNBC); total undisclosed
How it started
Luke Iseman, a serial inventor and former Y Combinator hardware director, believed research into solar geoengineering was too slow. He started releasing sulfur dioxide particles with balloons, raised venture capital and brought on Andrew Song to run sales.
What happened
Make Sunsets planned to launch three latex weather balloons releasing 10 to 500 grams of sulfur dioxide in January, drawing criticism as hasty and unsophisticated, with no international agreements overseeing the field. On Friday 13 January 2023 Mexico's government said it would 'prohibit and, where appropriate, stop' solar geoengineering experimentation.
How it ended up
On 18 January 2023 Make Sunsets said it would cease operations until it has more regulatory clarity, and published a mea culpa post.
What has to be true
Mexico said there were no international agreements covering solar geoengineering, and called such experiments risky for a minority's economic gain.
The lack of an international governance structure was a big concern for industry watchers.
Sunlight reflection might be among the fastest and cheapest ways to cool the planet, but it is not known whether its harms, which may include ozone damage and acid rain, could be worse than warming.
What can be applied
Experiments that change a shared commons need the host country and the scientific community on board first; moving fast on the assumption of forgiveness can end in a forced pause.
Aftermath
As of 18 January 2023, Make Sunsets had paused operations and said it supported scientific expertise and oversight, while its investor insisted it was not closing. The company says emissions cuts are still needed; CNBC notes the US was preparing a five-year research plan on the topic.
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