EPA head demands answers from company putting sulfur dioxide into the air to address global warming

Environmental Protection Agency Administrator Lee Zeldin is demanding a company that deliberately sends sulfur dioxide into the air to combat global warming provide detailed information on its practices. Critics of the practice, which is called geoengineering, say it puts potentially harmful pollutants into the air and needs more oversight. 

The company Zeldin is scrutinizing, Make Sunsets, sells “cooling credits.” The credits pay to launch weather balloons made of biodegradable latex containing hydrogen and sulfur dioxide. According to the company, each $5 credit it sells offsets the warming impact of one ton of carbon dioxide for one year. 

Last year, the company posted on its X account videos of balloon launches. According to the Make Sunsets website, the company has sold 125,717 “cooling credits” since February 2023, delivered by 147 balloons. As the balloon rises, the decreasing air pressure causes it to burst. They try to make the balloon burst above 66,000 feet, upon which they issue the “cooling credits.” 

Worldwide interest

Make Sunsets was founded by entrepreneur Luke Iseman and former account executive Andrew Song. The company is backed by venture capitalists Boost VC, Draper Associates, Pioneer Fund and unnamed “angel investors.” 

The company isn’t the only company looking at various approaches to geoengineering, nor is it a new concept. More than a decade ago, billionaire Microsoft founder Bill Gates was lobbying governments and international organizations to back research into how sulfur dioxide could be used to counteract global warming. 

Last year, the The New York Times reported on an experiment by University of Washington researchers on the deck of a decommissioned aircraft carrier in Alameda, California. The researchers sprayed an aerosol of sea salt to brighten clouds and make them reflect more sunlight. 

This May, experts and advocates of geoengineering – also called solar radiation modification (SRM) – are gathering for a conference on the topic. The “Degrees 2025 Global Forum” features an agenda full of speakers from around the world. 

"Just crazy"

The interest in geoengineering is driven by claims that climate change is producing dangerous outcomes, which many experts dispute. With global emissions continuing to rise despite trillions spent pursuing “net zero” – which is balancing the amount of greenhouse gases released into the atmosphere with the amount removed – geoengineering proponents say it’s a “Plan B” to stop global warming. 

Critics of geoengineering say it’s potentially dangerous and possibly unnecessary. 

Steve Milloy, senior legal fellow with the Energy and Environmental Legal Institute and publisher of “JunkScience.com,” told Just the News that the balloons Make Sunsets is sending up are likely harmless because the scale of the operation is so small. To have any significant impact on global temperatures, Milloy said, the operation would have to put tons of sulfur dioxide into the atmosphere, which would cause harm. 

“All this stuff is just kind of crazy because – well, it's not kind of crazy, it's just crazy. In the first place, it's really not going to work. For it to work, you'd have to do it on such a scale that we would have acid rain again,” Milloy said. 

During the 1970s and 1980s, acid rain became a widespread environmental concern, explored in situation comedies and news reports. Acid rain falls when sulfur dioxide and nitrogen oxides are emitted into the atmosphere and transported by wind and air currents. The two gases react with water, oxygen and other chemicals to form sulfuric and nitric acids. They mix with water condensing in the atmosphere and fall to the ground. 

Dr. Matthew Wielicki, a geologist and author of the “Irrational Fear” Substack, explains in an article on geoengineering that beginning in the 1990s, the U.S. began implementing regulations aimed at sulfur emissions from diesel engines. Ultra-low-sulfur diesel was expensive and drove up the cost of shipping, which drove up the cost of everything, Wielicki explains. Unlike carbon dioxide, which stimulates plant growth, sulfur dioxide, Wielicki wrote, causes genuine environmental harm, including soil acidification, forest degradation, infrastructure corrosion and severe aquatic ecosystem damage.

“This tangible harm justified sulfur regulations," Wielicki warns. "Yet now, geoengineering advocates want to intentionally pump sulfur into our atmosphere, ignoring decades of clear scientific evidence regarding sulfur's proven environmental and health damage.” 

"Partly a cult"

Just the News reached out to Make Sunsets to ask about the safety of their operation and Zeldin’s request for details about its operation, but didn’t receive a response. 

Make Sunsets co-founder Iseman told the MIT Technology Review the company is part entrepreneurial and partly an act of geoengineering activism meant to get attention. 

“We joke slash not joke that this is partly a company and partly a cult,” he told the Review. With the threat of climate change, he said, “It’s morally wrong, in my opinion, for us not to be doing this.” 

In a press release, Zeldin said Make Sunsets is banned in Mexico, and it’s not clear the company has been in contact with state, local or federal agencies. Noting the potential environmental and respiratory health impacts of sulfur dioxide, the EPA states that the gas has been regulated since 1971. 

The EPA told Just the News that Make Sunsets is the only entity in the U.S. currently launching sulfur dioxide balloons with the intention of geoengineering. The agency gave the company a deadline of May 14 to answer its questions. In a letter to the company, the EPA warns that a failure to comply in a timely manner could result in monetary penalties. 

The EPA is asking Make Sunsets to provide information on the physical location of the company, the number of employees, its annual revenues and its expenditures for carbon credits. It’s also asking for detailed information on its balloon launches and their contents, including what gases they contain and how they’re sourced. 

The agency is also asking about any communications the company has had with federal, state and local authorities, and any enforcement actions, such as consent decrees, related to air emissions that apply to Make Sunset’s operations. 

Global implications

Milloy said that the science behind the cooling effect of sulfur dioxide is solid. Research has shown, for example, the 2001 Mount Pinatubo eruption lowered global temperatures for about 15 months after the eruption due to the cooling effect of the particles it put into the atmosphere. 

The problem with geoengineering, he said, is that lowering temperatures by increasing sunlight reflection will impact agriculture, in addition to acid rain. On a global scale, it could create all kinds of problems. 

“Do we really want the Chinese getting involved in this and trying to control our weather?” Milloy asked.