Diamond dust geoengineering: Costly cooling with controversy
Scientists in the latest study suggest that dispersing diamond dust using a geoengineering technique known as stratospheric aerosol injection (SAI) could mitigate nearly all human-caused warming and adverse climate changes since the Industrial Revolution.
Although scientists remain divided, and the cost of implementation could reach hundreds of trillions of dollars, it is undeniable that geoengineering (SAI)—particularly its most recognized technique, stratospheric aerosol injection—could immediately impact climate change by reducing the amount of solar energy that reaches Earth. This could provide us time to achieve net-zero carbon dioxide emissions in the long term. The UN warns that we are now "walking on a planetary tightrope" and that carbon emissions must be cut in half immediately to prevent a climate catastrophe.
Diamonds could cool a heated Earth by 1°C annually
Scientists did not initially consider dispersing only diamond dust into the atmosphere; they also evaluated other materials, such as calcite, aluminum, silicon carbide, and sulfur dioxide. In a new study published on December 16 in the scientific journal Environmental Research: Climate, researchers from the Institute for Atmospheric and Climate Science in Zurich, Switzerland (ETH), confirmed that diamonds are the most effective material for atmospheric dispersal.
They calculated that launching 5 million metric tonnes of diamond dust into the stratosphere each year could cool the planet by 1°C due to the reflective properties of these precious stones. This amount of cooling would significantly help limit global warming, which began in the latter half of the 19th century and currently stands at approximately 1.36°C, according to NASA data.
The team also compared diamond particles' cooling efficiency with aluminum and calcite particles. They found that the diamond dust needed to cool the planet by 1°C—5 million tonnes annually—constituted about one-third of the other materials required to achieve the same cooling effect.
Sulfur dioxide could cause acid rain, among other issues
Researchers highlighted that diamond particles possess exceptional light and heat-reflecting properties, enabling them to stay suspended in the atmosphere for an ideal duration without clustering. According to Sandro Vattioni, a co-author of the study and a researcher in experimental atmospheric physics at ETH Zurich, diamond dust's highly reflective nature and its resistance to clumping are due to its high resistance to clumping. In contrast, other materials tend to absorb heat rather than redirect it back into space, as noted by Live Science.
Scientists had previously explored the possibility of pumping sulfur dioxide into the stratosphere to control climate change. They discovered that although sulfuric acid aerosols absorb a substantial amount of solar and terrestrial heat, they could lead to undesirable effects—such as acid rain and damage to the ozone layer—while diamond dust is chemically inert. Scientists have now discovered that diamond particles would not cause stratospheric warming or other significant disruptions.
The diamond method could cost nearly $200 trillion
The new study did not estimate the production costs of diamonds for geoengineering purposes. Still, synthetic diamonds would likely be cheaper than mined diamonds, according to Vattioni, as quoted by Live Science. However, the costs and energy demands of these different materials remain unclear. A previous study (from 2020) estimated that SAI with sulfur dioxide from 2035 to 2100 would cost $24 billion (CAD) annually, and the cost of aluminum and calcite would likely fall into the same range, Vattioni said. The diamond bill would be significantly higher—the 2020 study calculated a total cost over 65 years at $234 trillion (CAD).
Weather-altering techniques are controversial, even for scientists
For now, there is considerable uncertainty surrounding geoengineering (SAI), and scientists are far from implementing it. Some experts oppose conducting this type of research altogether due to unforeseen consequences it may have and because they claim it diverts funds from other climate research.
"We really run the danger of passing some irreversible climate tipping points and ecological tipping points, and SAI could potentially help to avoid passing these tipping points until we have reached the net zero goal," commented Sandro Vattioni, a researcher in experimental atmospheric physics at the Swiss Federal Institute of Technology in Zurich (ETH Zurich), on the Live Science portal.
