10 Billion Dollars Annually to Cool the Planet.. And Scientists Warn of Risks

- One company has a seemingly simple plan to help save the planet, which involves using a food and mineral additive that gives eggshells their hardness, producing nanoparticles from both, and then spraying these particles into the atmosphere to cool the world. The Israeli-American company "Stardust Solutions," founded in 2023 and led by a nuclear physicist who previously worked for the Israeli government, is pushing forward in the race to develop "solar geoengineering," a controversial technology aimed at artificially lowering global temperatures by reducing the amount of sunlight reaching the Earth.

There are many different methods of solar geoengineering, but the one that "Stardust" focuses on is the method of spraying nanoparticles into the stratosphere using high-flying aircraft or balloons, with the goal of reflecting solar energy away from the Earth and back into space. This process is an artificial version of a natural phenomenon.

Sometimes, volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, which can lead to a temporary decrease in global temperatures. In 1991, the eruption of Mount Pinatubo in the Philippines released enough sulfur dioxide into the atmosphere, resulting in a temperature drop of 0.5 degrees Celsius (0.9 degrees Fahrenheit) for more than a year.

As humans continue to burn fossil fuels and cause the planet to heat up, interest is growing in the question of whether solar geoengineering can be moved from the realm of theory to practical application. Yanai Yedvab, CEO of "Stardust," stated that this technology represents a "crucial tool" that governments should consider in light of the alarming rise in global temperatures, but he emphasized that it is not a magic solution to the problem of climate change, nor a substitute for addressing its root causes.

However, many scientists have expressed concerns that solar geoengineering could lead to catastrophic global consequences, such as drastic changes in weather patterns. Some experts also warn that a profit-driven company developing proprietary technology may have enormous and unpredictable repercussions.

On his part, Raymond Pierrehumbert, a professor of planetary physics at the University of Oxford, said: "When the whole world is at stake, the issue of meeting the aspirations of venture capitalists for profit should not enter into decisions about whether any of these technologies should be used, and which of them should be used." Scientists have been studying solar geoengineering for decades, but private companies have started to emerge in this field.

Among the most prominent is "Stardust," which is the best-funded, having raised $75 million from investors. Yedvab and his co-founder Amjad Spector came up with the idea of working in the field of solar geoengineering while searching for ways to help address the climate crisis.

Regarding the spraying of particles in the atmosphere, most research and development in solar geoengineering focuses on sulfur dioxide, in an attempt to mimic the effects of volcanic eruptions. However, sulfur dioxide can have negative effects, including contributing to acid rain and depleting the ozone layer.

Yedvab explained that "Stardust" wanted to develop a material that "is better, safer, and controllable." Earlier this year, the company revealed designs for its particles in a series of scientific papers that are still awaiting peer review.

The company produced two types of particles: the first is made of amorphous silica, which is commonly used as an anti-caking additive in food, toothpaste, and cosmetics, while the second consists of a core of calcium carbonate, the main component of eggshells, surrounded by a shell of amorphous silica. Both compounds occur naturally and can also be produced synthetically.

Yedfab pointed out that they are commonly used materials. For example, amorphous silica was released in the New York City subway in 2016, as part of a test conducted by the Department of Homeland Security to simulate the effects of a potential biological attack.

Yedfab believes that this incident helps clarify the perception of silica as a safe material. He noted that every million tons of particles could lead to a temperature reduction of about 0.5 degrees Celsius, and this amount would need to be replenished annually.

The cost of deploying every million tons would be about 10 billion dollars. He acknowledged that this is a huge amount, but it remains a small part of the damage caused by climate-related disasters.

In addition to concerns about private companies attempting to modify the climate, some are worried about the potential impacts on global climate and weather, as well as on human health. For his part, David Keith, a professor of geophysical sciences at the University of Chicago known for his research on solar geoengineering, stated that Stardust "greatly exaggerates when it claims that the risks of (its) particles are lower than those of sulfur."

Among the concerns is what is known as the "passenger parasite hypothesis," which is the idea that particles in the air may capture metals or other materials that could cause harm when inhaled by humans. Stardust clarified that the design of its particles takes these risks into account.

However, Kelly Wanser, the executive director of the non-profit organization "SilverLining" focused on climate research, stated that it is still unclear whether these particles will work when used on a large scale, and how they might behave within the atmosphere. Berhambert said, "Solar geoengineering deals with some of the less understood aspects of the climate system," adding that any small-scale experiment cannot reveal how Earth's systems would respond to a large-scale deployment.

So far, the company's tests have been limited to the laboratory. External testing represents the next step, but previous experiments suggest that this phase could be highly complex and controversial.

In 2021, plans by scientists from Harvard University to conduct trial flights related to solar geoengineering in the polar region of Sweden were canceled due to strong local opposition. A controversial experiment conducted by the American startup "Make Sunsets" in Mexico in 2022 also led the country to ban solar geoengineering experiments.

"Stardust" hopes to begin external testing within the next few years. Yedvab stated that the company will only conduct these tests "under the supervision and direct guidance of governments."

Nevertheless, "Stardust" is a for-profit company and has a financial interest in using this technology, according to some experts, which has raised concerns. Keith wrote in a blog post last year that "proprietary technology and profit motives directly conflict with the level of transparency needed to legitimize solar geoengineering research."

Scientists say that solar geoengineering could open the door to a wide range of unintended consequences, including the potential to alter rainfall patterns and shift monsoon systems, which could have significant implications for food production. Perhaps the most concerning possibility is what is known as the "termination shock," meaning that once solar geoengineering is initiated, it may need to be continued indefinitely.

Birhambert stated that if the process were to stop suddenly, "the world would find itself facing a catastrophic and sudden rise in temperatures occurring within just a few years." Stardust claims that the impact of its technology can be increased or decreased, meaning that deployment can be gradually scaled back.

Yedfab noted that particles fall out of the atmosphere after about a year, "so the level of cooling remains a continuous and adjustable option in the hands of governments, and termination shock can be avoided." A recent study concluded that the use of this technology would lead to a "profound state of uncertainty at the system level" and to "the potential for increased destabilization of the global climate system."

There are also concerns that this technology could be used as an excuse to avoid making significant reductions in the pollution that causes global warming, which requires a substantial decrease in the amount of fossil fuels we burn.