Breaking News
Investing Pro 0
Free Webinar - Master Indicators: Maximized Trading Potential! | Thursday, June 8 | 12:30PM EDT Enroll Now

How two weather balloons led Mexico to ban solar geoengineering

Published Mar 27, 2023 06:33AM ET Updated Mar 27, 2023 04:10PM ET
Saved. See Saved Items.
This article has already been saved in your Saved Items
2/2 © Reuters. Luke Iseman launches a balloon in Baja California, Mexico, April 11, 2022. Luke Iseman/Handout via REUTERS 2/2

By Cassandra Garrison

MEXICO CITY (Reuters) - On an April day, the founder of a U.S. startup called Make Sunsets stood outside a camper van in Mexico’s Baja California and released two weather balloons containing sulfur dioxide into the air, letting them float towards the stratosphere.

Entrepreneur Luke Iseman said the sulfur dioxide in the balloons would deflect sunlight and cool the atmosphere, a controversial climate strategy known as solar geoengineering. Mexico said the launch violated its national sovereignty.

Iseman, 39, said he does not know what happened to the balloons. But the unauthorized release, which became public in January, has already had an impact: setting off a series of responses that could set the rules for future study of geoengineering, especially by private companies, in Mexico and around the world.

The Mexican government told Reuters it is now actively drafting “new regulations and standards” to prohibit solar geoengineering inside the country. Mexico also plans to rally other countries to ban the climate strategy, a senior government official told Reuters.

While the Mexican government announced its intention to ban solar geoengineering in January, its current actions and plans to discuss geoengineering bans with other countries have not been previously reported.  

"Progress is being made... to prepare the new regulations and norms on geoengineering, that is, to advance an official Mexican standard that prohibits said activity in the national territory," Mexico’s environment ministry said in a written statement to Reuters.

The backlash from Mexico arrives as growing numbers of scientists and policy makers are urging further study of solar geoengineering, recognizing that emissions cuts alone will not limit dangerous climate change and that additional innovations may be needed.


Climate policy experts said Mexico is in a position to help set the rules for future geoengineering research.

“A country like Mexico could start pulling together other countries and say: ‘Let’s work on this together and see how we can ban it together or make it happen properly together,’” said  Janos Pasztor, executive director of the Carnegie Climate Governance Initiative (C2G), which advises on governance of solar geoengineering and other climate-altering technologies.

The Mexican environment ministry statement said it would explore using the Convention on Biological Diversity's call for a moratorium on “climate-related geoengineering activities” to enforce its ban.

Agustin Avila, a senior environment ministry official, told Reuters Mexico will also try to find common ground with other countries on geoengineering at the COP global climate summit in the United Arab Emirates this year.

The Mexican government said Make Sunsets’ balloon launch highlighted the ethical problems of allowing private companies to conduct geoengineering events.

"Why is this company, located in the United States, coming to do experiments in Mexico and not in the United States?" said Avila.

Iseman told Reuters in an email he chose Mexico because "most researchers report that particles launched into the stratosphere near the tropics will create more cooling by staying up longer." Also, he had a truck and camper in Baja and thinks the region is beautiful, he wrote.

David Keith, a professor of applied physics and public policy at Harvard University who has dedicated much of his research to solar geoengineering, called Iseman's launch a "stunt."

Iseman has a background in business, not science, but said he consulted with climate scientists. Other innovative startups were ridiculed in their early days, he said. "If the 'responsible experts' were solving the problem, we wouldn't have to," he said in an email.

Until Mexico's dispute with Make Sunsets, solar geoengineering had been gaining attention from policy makers and scientists as a possible solution to climate change, and limited research funding.

The strategy, also known as  Solar Radiation Management, seeks to mimic the natural cooling effects of volcanic eruptions when ash clouds reflect back enough sunlight to reduce the warming of the earth by using planes or balloons to disperse tiny particles in the stratosphere.   

Last month, 60 scientists including former NASA climate scientist James Hansen signed a letter in support of further research.  

The Degrees Initiative, a UK-based non-government group, awarded $900,000 for research into the impacts of solar geoengineering on weather patterns, wildlife and glaciers to scientists from Chile, India, Nigeria and other countries.

The U.N. Environment Program in late February also recommended further study of geoengineering.

Yet some scientists remain opposed to further research, arguing that large-scale interventions in the atmosphere risk triggering extreme and unpredictable weather changes, including major droughts that would severely impact agriculture and food supply.

In 2021, the Swedish government grounded a Harvard-led study by Frank Keutsch and Keith, which planned to spray calcium carbonate dust into the atmosphere to deflect sunlight after indigenous Saami people accused researchers of lacking respect for "Mother Earth."

Frances Beinecke, a veteran environmental activist and board member of the Climate Overshoot Commission, a think tank focused on developing strategies to reduce the risk of overshooting 1.5 C in warming, said the Make Sunsets episode underscores the urgency of developing a regulatory framework that would allow further study of geoengineering and set safe and equitable rules for its use.

“The Mexico example illustrated to us that it’s not only governance to consider whether or not to utilize it, but you need governance in the research phase,” she said. “People can’t just go all over the world and launch field experiments without some kind of oversight.”

Iseman said he would welcome clearer regulation but that the international community is moving "too slowly."

Mexico has not set a date for implementing its ban, a spokeswoman for the environmental ministry said.

And it's unclear what effect a ban might have. Keith argues a ban is unenforceable. "You can't write legislation that says you can't put sulfur in the stratosphere since every commercial flight does that," he told Reuters.

Others note that a ban on geoengineering on Mexico's territory would offer no protection from the planet-scale impact of future experiments by any of its neighbors. 

“It could happen literally next door. In terms of impacts on the world, it's the same," Pasztor said

Meanwhile, Make Sunsets said in a Feb. 21 blog post it had performed three additional launches near Reno, Nevada.

The National Oceanic and Atmospheric Administration (NOAA) said Make Sunsets did not report the launches. "The Weather Modification Act requires that any activity performed with the intention of producing artificial changes in the composition, behavior, or dynamics of the atmosphere be reported to the NOAA Weather Program Office before the commencement of such project or activity," NOAA told Reuters.

Iseman said he did seek clearance from the Federal Aviation Authority, but did not disclose the balloons contained sulfur dioxide. "As far as I can tell, there isn't any rule that would require us to do so - or even anyone who it would be relevant to notify," he said. 

(This story has been corrected to say that David Keith was involved in the Harvard study, not lead it, in paragraph 23)

How two weather balloons led Mexico to ban solar geoengineering

Related Articles

Add a Comment

Comment Guidelines

We encourage you to use comments to engage with other users, share your perspective and ask questions of authors and each other. However, in order to maintain the high level of discourse we’ve all come to value and expect, please keep the following criteria in mind:  

  •            Enrich the conversation, don’t trash it.

  •           Stay focused and on track. Only post material that’s relevant to the topic being discussed. 

  •           Be respectful. Even negative opinions can be framed positively and diplomatically. Avoid profanity, slander or personal attacks directed at an author or another user. Racism, sexism and other forms of discrimination will not be tolerated.

  • Use standard writing style. Include punctuation and upper and lower cases. Comments that are written in all caps and contain excessive use of symbols will be removed.
  • NOTE: Spam and/or promotional messages and comments containing links will be removed. Phone numbers, email addresses, links to personal or business websites, Skype/Telegram/WhatsApp etc. addresses (including links to groups) will also be removed; self-promotional material or business-related solicitations or PR (ie, contact me for signals/advice etc.), and/or any other comment that contains personal contact specifcs or advertising will be removed as well. In addition, any of the above-mentioned violations may result in suspension of your account.
  • Doxxing. We do not allow any sharing of private or personal contact or other information about any individual or organization. This will result in immediate suspension of the commentor and his or her account.
  • Don’t monopolize the conversation. We appreciate passion and conviction, but we also strongly believe in giving everyone a chance to air their point of view. Therefore, in addition to civil interaction, we expect commenters to offer their opinions succinctly and thoughtfully, but not so repeatedly that others are annoyed or offended. If we receive complaints about individuals who take over a thread or forum, we reserve the right to ban them from the site, without recourse.
  • Only English comments will be allowed.
  • Any comment you publish, together with your profile, will be public on and may be indexed and available through third party search engines, such as Google.

Perpetrators of spam or abuse will be deleted from the site and prohibited from future registration at’s discretion.

Write your thoughts here
Are you sure you want to delete this chart?
Post also to:
Replace the attached chart with a new chart ?
Your ability to comment is currently suspended due to negative user reports. Your status will be reviewed by our moderators.
Please wait a minute before you try to comment again.
Thanks for your comment. Please note that all comments are pending until approved by our moderators. It may therefore take some time before it appears on our website.
Comments (1)
John Bozanich
John Bozanich Mar 27, 2023 2:48PM ET
Saved. See Saved Items.
This comment has already been saved in your Saved Items
yeah like there have not already been millions of tons of chemicals sprayed above us before our very eyes since 1997.. and practically everyday.. and how many even notice let alone know the devastating consequences to ozone layer depletion and fallout pollution of ecosystem and humans.
Are you sure you want to delete this chart?
Replace the attached chart with a new chart ?
Your ability to comment is currently suspended due to negative user reports. Your status will be reviewed by our moderators.
Please wait a minute before you try to comment again.
Add Chart to Comment
Confirm Block

Are you sure you want to block %USER_NAME%?

By doing so, you and %USER_NAME% will not be able to see any of each other's's posts.

%USER_NAME% was successfully added to your Block List

Since you’ve just unblocked this person, you must wait 48 hours before renewing the block.

Report this comment

I feel that this comment is:

Comment flagged

Thank You!

Your report has been sent to our moderators for review
Continue with Google
Sign up with Email