Mexico Bans California Climate Startup’s Experiments to Cool Atmosphere

Make Sunsets, a firm led by tech entrepreneur Luke Iseman, had raised $750,000 in venture capital and other funds with the idea of selling “cooling credits” to U.S. firms, according to Mr. Iseman. He said the money would be used to release sulfur dioxide into the stratosphere, with the idea that the particles—if spread across a wide area—would reflect sunlight away from the Earth and cool the atmosphere. The company promised that a “cooling credit” would offset the equivalent of a ton of carbon dioxide for a year.

The so-called solar-geoengineering project launched one balloon in 2022 and was planning more launches this month from a site in the Mexican state of Baja California Sur.

Critics of solar geoengineering say not enough is known about how the particles will interact with other chemicals in the atmosphere and whether there will be unintended environmental effects.

On Jan. 13, Mexico’s Ministry of Environment and Natural Resources, or Semarnat, issued a statement stating it would prohibit the project from going forward.

The agency said any large-scale projects—and those that are seemingly large-scale but under development—involving solar geoengineering within Mexico would be halted.

Mexico’s Semarnat said it opposes the launches because there are currently no international agreements that address or regulate solar geoengineering activities. In 2010, delegates to the United Nations Convention on Biodiversity agreed to a nonbinding moratorium on geoengineering, which permitted small-scale research. Mexico is a signatory to the convention, while the U.S. isn’t.

“I expected and hoped for dialogue,” Mr. Iseman said from a small town in the Mexican state of Baja California Sur. “I’m surprised by the speed and scope of the response.” Mr. Iseman didn’t ask for permission from the local government or consult locals about the experiments, according to the Mexican government.

Mr. Iseman said he launched a single weather balloon in April carrying several grams of sulfur dioxide, and that he was planning to launch several more balloons this month with larger amounts. He added that he was using weather balloons purchased online, and sulfur dioxide from an industrial supplier. The Make Sunsets founder said he was disappointed by the Mexican government’s response and agreed to pull the plug on his effort.

Mr. Iseman, who graduated from the Wharton School at the University of Pennsylvania, said he started the project because he felt existing efforts were stalled by government inaction. He said he informally consulted with scientists about geoengineering, but devised the designs and plan on his own.

Researchers who examined Make Sunsets’ plan said the small amount of sulfur dioxide carried by the weather balloons probably wouldn’t have resulted in much atmospheric cooling. At the same time, the researchers said the concept of solar geoengineering might have some merit once more research is conducted.

Although much discussed, solar geoengineering has never been tested in the field, and it risks causing other effects in the atmosphere, according to climate scientists. A 2019 study by Harvard University scientists estimated that climate warming could be cut in half using reflective airborne particles. However, there might be unexpected reduction in rainfall in some parts of the world, according to the study, published in the journal Nature Climate Change. 

In March 2021, a committee of the National Academies of Sciences, Engineering, and Medicine recommended that the U.S. invest as much as $200 million in a new solar-geoengineering research program, subject to public input and with careful governance over outdoor experiments.

In April 2021, a field experiment involving a balloon release over Sweden—designed by Harvard University researchers and funded by private philanthropists—was halted amid opposition by environmental and indigenous groups.

Last year Congress asked the White House Office of Science and Technology Policy and the National Oceanic and Atmospheric Administration to develop a set of guidelines on solar-geoengineering research that will be issued this spring, according to an OSTP spokesperson.

At the same time, the agency said the research guidelines aren’t a substitute for reducing greenhouse gases produced by industrial activity, gases that are rapidly warming the atmosphere, oceans and land, according to the Intergovernmental Panel on Climate Change. 

“The Biden-Harris Administration strongly affirms that immediate, sustained, and effective reductions of global greenhouse gas emissions, effective and responsible CO2 removal, coupled with robust adaptation, are required to slow the pace of climate change and limit warming to 1.5 degrees Celsius,” said the OSTP spokesperson.

For his part, Mr. Iseman said he is not finished with solar geoengineering, a concept he says he learned about by listening to an audio version of “Termination Shock,” a 2021 sci-fi novel by author Neal Stephenson in which a billionaire launched sulfur particles into the atmosphere with cannons from a site near the Texas-Mexico border.

“One of my dreams is that we could, in some distant future, grow Make Sunsets legally and responsibly,” Mr. Iseman said.

Write to Eric Niiler at [email protected]