
Make Sunsets Conducts Climate Engineering Tests Over Baja California, Injecting Reflective Particles
Key Takeaways
- Private geoengineering field tests occurred, including Make Sunsets in Baja California and Stardust Solutions.
- EU warns on solar geoengineering risks while weighing research versus ban.
- Global governance questions emerge as policymakers scrutinize risks and legitimacy of geoengineering.
Make Sunsets in Baja
A U.S. start-up, Make Sunsets, announced during the Christmas holidays that it had conducted a pair of climate engineering tests in “California messicana,” aiming to “colorare i tramonti di rosso cupo” by injecting reflective particles in the lower stratosphere about 20 chilometri dal suolo.
“Editing:Megan Rowling Campaigners working to limit the use of controversial sun-dimming technology have praised the Europe’s foreign ministers for warning of the risks such technology poses, but opinions remain split over whether it merits more research, with the European Union keeping its position open for now”
According to the start-up’s chief executive Luke Iserman, Make Sunsets released “due comunissimi palloni sonda in lattice” in the skies of Baja California, carrying a few grams of anidride solforosa that were supposed to explode at very low external atmospheric pressures.

The Le Scienze account says the conditional is necessary because the aerostats were “del tutto privi di strumentazione” and it was not possible to recover debris, since even a geolocation system was missing.
Le Scienze quotes climatologist Daniele Visioni saying, “Si tratta di una soluzione che non sostituisce l’inderogabile riduzione delle emissioni di gas serra,” while framing the activity as a visibility push and a prompt for policymakers and the scientific community to confront geoengineering.
The same article adds that a 2018 study in “Environment Research Letters” by researchers from Harvard and Yale estimated that a geoengineering program capable of halving incident solar radiation could cost “2,25 miliardi di dollari” in its first 15 years of operation.
EU debate and moratorium
In Luxembourg, EU foreign ministers representing the EU’s 27 member states signed off on a statement agreeing for the first time that they were “concerned that large-scale climate interventions, in particular solar radiation modification (SRM), pose significant risks for the climate, the environment, security and geopolitics”.
The statement, issued in late April, called for “a moratorium on deployment of SRM technologies” and for “the full application of the precautionary principle to geoengineering,” while also urging the EU to engage in international talks on governance arrangements including research.

Giulia Neri of the Centre for Future Generations told Climate Home News that the EU’s statement sends “an important and timely signal on the need for rules governing SRM,” and Matthias Honneger added that ministers in charge of research “might also consider how responsible public research under European oversight can help maintain Europe’s influence”.
Campaigners Mary Chuch and political scientist Frank Biermann welcomed the emphasis on precaution but argued for preventing research that could lead to development and use, with Biermann saying, “As an immediate first step, the European Union must prevent research that could lead to the development and use of solar geoengineering technologies,” and Chuch calling solar geoengineering “inherently unpredictable”.
The article notes that SRM is currently legal in most nations, while a de facto global moratorium has been in place since 2010 under the Convention on Biological Diversity, with exceptions for small-scale scientific research studies.
Private SRM and public cost
Le Monde.fr reports that after nearly two years of research and development, including field experiments, the Israeli-American startup Stardust Solutions secured “$60 million” in venture capital investments from Silicon Valley, about “€51.1 million,” and also began lobbying activities with the U.S. Congress.
“After nearly two years of research and development, including field experiments, it was announced at the end of October that the Israeli-American startup Stardust Solutions had secured $60 million in venture capital investments from Silicon Valley (approximately €51”
The outlet describes Stardust as a for-profit company developing patented technologies for the injection of stratospheric aerosols, warning that “Private geoengineering has a cost, and that cost is public,” while noting the company provided no public data, no independent audit report, and no evidence of public consultation.
Le Scienze had earlier framed governance as the key uncertainty, quoting climatologist Daniele Visioni that “La vera incognita è chi terrà la mano sul termostato,” and linking the stakes to geopolitics, justice, and inequalities.
CORDIS’ IMPLICC project, funded by the EU, studied solar radiation management techniques including “iniezioni di zolfo nella stratosfera” and found that effectiveness on solar forcing is “inferiore al forcing CO2,” while concluding that to balance temperature increases would require “il 10-20 % di ingegneria in più rispetto al previsto.”
Startmag’s excerpted account of a Guardian report says the European Commission’s scientific advisers urged Europe to ban “space mirrors” and other solar geoengineering techniques, while leaving “la porta” open to research into development, and it adds that the report found the “profound uncertainties” of solar geoengineering “non sono compatibili” with the EU’s precautionary principle and duty to do no harm.
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