What was once dismissed as a far-fetched conspiracy theory is now making its way into mainstream scientific discussions: spraying reflective particles into the atmosphere to fight “climate change.”
The geoengineering method, known as stratospheric aerosol injection (SAI), has long derided as a “conspiracy theory”, but now mainstream scientists are promoting it as a viable way to “buy us some time” to combat the alleged threat of “climate change.”
Scientists now propose using diamond dust—tiny reflective particles—to offset nearly all the warming caused by human activity since the industrial revolution. The idea, they say, could temporarily cool the planet by 1.8 degrees Fahrenheit (1 degree Celsius), slowing the pace of climate change while governments work toward achieving net-zero carbon emissions.
“It’s a very controversial topic,” said Sandro Vattioni, a researcher in experimental atmospheric physics at ETH Zurich and co-author of the study. “There are many scientists who want to forbid doing research—even research—on the topic.”
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| The new study did not estimate the cost of producing diamonds for geoengineering, but synthetic diamonds would likely be cheaper than mined diamonds, Vattioni said. |
The study, published in October, modeled the effects of injecting 5.5 million tons (5 million metric tons) of diamond dust into the stratosphere annually. The stratosphere, a layer of Earth’s atmosphere between 7.5 and 31 miles above the surface, provides a stable environment where the particles could remain suspended for over a year, reflecting sunlight back into space.
The idea of stratospheric aerosol injection takes inspiration from the natural cooling effects observed after major volcanic eruptions. Volcanoes eject sulfur dioxide, which transforms into sulfate aerosols in the stratosphere. These fine particles reflect sunlight, cooling the planet temporarily. However, using sulfuric aerosols to combat climate change has significant downsides, Vattioni explained.
Sulfuric acid particles can absorb heat, potentially warming the stratosphere and disrupting global wind and precipitation patterns. These effects could cascade down to the troposphere, causing unintended environmental and weather consequences.
Diamonds, according to the study, avoid these pitfalls. Their high reflectivity and resistance to clumping make them an ideal candidate for geoengineering. Unlike sulfur-based aerosols, diamond particles reflect sunlight without absorbing heat or warming the stratosphere. This minimizes the risk of disturbing global weather systems.
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| Commercial airplanes and experimental aircraft, such as NASA’s Stratospheric Observatory for Infrared Astronomy (pictured above) can operate in the stratosphere. |
“The material properties of diamond powder make it particularly well-suited for this purpose,” Vattioni said.
Despite its promise, the scheme would not come cheap. Spraying millions of tons of diamond dust annually would cost an estimated $175 trillion, raising questions about whether such an investment is feasible—or ethical.
Critics argue that geoengineering efforts could divert resources and attention from reducing greenhouse gas emissions, leaving humanity dependent on short-term solutions instead of addressing the root causes of climate change.
Others worry about potential unintended consequences, including the political and ethical implications of deliberately manipulating Earth’s climate.
