GabyThis idea sounds like it was borrowed from a science fiction blockbuster. But it’s not: real scientists are seriously weighing its pros and cons. A team at the Institute of Atmospheric and Climate Science at the Swiss Federal Institute of Technology Zurich thinks spraying millions of tons of diamonds into the sky could be the climate solution the world has been searching for. There’s one catch: the project is incredibly expensive (we’ll get to the exact figure shortly). The team calculated the cost while studying how spraying various aerosols into the stratosphere would cool the Earth and found diamonds performed much better than other solids they modeled. Their model showed that releasing 5 million tons of diamond dust into the stratosphere each year could cool the planet by a staggering 1.6 °C.
What conclusions did the scientists reach? In their new study, the team tested whether dispersing sunlight-reflecting particles via stratospheric aerosol injection (SAI) could cool the planet. Most previous work has focused on injecting sulfur dioxide (SO2) into the atmosphere — the same process that happens in volcanic eruptions. A paper published in Geophysical Research Letters says that approach has several limitations. Sulfur dioxide not only causes acid rain but can also damage the ozone layer and disrupt weather patterns.
To address this, the researchers created a three-dimensional climate model that simulated spraying six solid substances into the stratosphere: diamond, calcite, aluminum, silicon carbide, anatase, and rutile.
This model let the scientists analyze how each particle absorbs or reflects heat, how long it would remain in the atmosphere, and whether particles would clump together. The results showed that diamond dust reflects sunlight most effectively, stays airborne longer, and resists clumping. Because diamonds are chemically inert, they wouldn’t cause acid rain, the Daily Mail reported.
“The side effects on circulation and climate, especially from injecting diamonds, could be significantly reduced compared to SO2, making diamond particles the most suitable for SAI in terms of optical properties compared to other materials studied,” the team explained. However, cooling the planet by 1.6 °C — enough to avoid the worst consequences of global warming — would require massive quantities of diamonds. In an interview with Science, lead author Sandro Vattioni said achieving that effect over 45 years would require spraying 5 million tons of diamond particles into the stratosphere each year, a program that could cost around $200 trillion by the end of the century.
What does that mean? The numbers make one conclusion clear: spraying diamonds into the sky is unlikely to happen any time soon. Still, the research provides a starting point for further exploration. The team proposes additional studies on particle agglomeration in turbulent aircraft trails and on measuring the optical properties of candidate solid materials.
Global greenhouse gas emissions keep rising, and Earth’s temperature continues to climb. Last month was the second-hottest September on record, with the average global air temperature reaching 16.17 °C. Several months in 2024 have already set new highs, including January, February, March, April, May, and June. Climate scientists around the world are urgently searching for ways to tackle the crisis. First and foremost, as is well known, we need to remove greenhouse gases from the air and limit future emissions.
