The dispersion of diamond dust into Earth's atmosphere could neutralize all the warming caused by human activity since the Industrial Revolution, reports LiveScience.
New research indicates that an annual release of 5.5 million tons of diamond dust into the stratosphere could cool the planet by 1 degree Celsius due to the reflective properties of these precious stones. According to NASA, such cooling would significantly help curb global warming, which began in the latter half of the 19th century and currently stands at around 1.36°C.
This study contributes to the field of geoengineering, which seeks ways to combat climate change by reducing the amount of energy received by Earth from the Sun.
"This is a highly controversial topic. There are many scientists who want to ban research—even scientific studies—on this subject," says co-author Sandro Vattioni from the Swiss Federal Institute of Technology in Zurich.
To mitigate the effects of global warming, researchers have long suggested using tiny particles, or aerosols, that reflect sunlight back into space. According to the researchers, these aerosols need to be sprayed into the stratosphere, which lies between 12 and 50 km above Earth's surface. This altitude ensures that the dispersed particles will remain in the sky for a year before falling to the ground.
Such ideas were inspired by the cooling process that sometimes occurs after major volcanic eruptions. Volcanoes release massive clouds of sulfur dioxide. In the stratosphere, this gas transforms into sulfuric acid, which then condenses to form fine sulfate aerosols that reflect sunlight back into space, preventing it from reaching Earth and warming the planet.
Previous studies have explored the possibility of injecting sulfur dioxide into the stratosphere to combat climate change, but several undesirable side effects must be considered, Vattioni explains. Sulfuric acid aerosols absorb a significant amount of solar and terrestrial heat, meaning they could cause warming in the stratosphere, which might affect the circulating winds within it. According to him, any disturbances could spread to the troposphere—the layer of the atmosphere below the stratosphere and above the Earth's surface—and lead to disruptions in global precipitation patterns and circulation.
This is where diamonds could be beneficial, Vattioni noted.
In a modeling study published in October, he and his colleagues found that diamond particles would not cause stratospheric warming or any other noticeable disruptions. This is because diamond powder has an extremely high reflective capacity and does not clump together, which is why some other materials absorb heat instead of sending it back into space.
Several hundred high-altitude planes would need to continuously fly around the Earth, dispersing particles to achieve the required amount for cooling.
"We simply tested the theory with diamonds and did not consider the cost or how these particles could be mined. But obviously, these issues also need to be addressed," says the scientist.
The team compared the cooling effectiveness of diamond particles with that of aluminum and calcite particles using a Earth system model that simulates the complete climatic response to intervention. The researchers determined that to cool the planet by 1 degree, it would be necessary to spray 5.5 million tons of diamond dust annually.
The total project cost would amount to $175 trillion over 65 years.
Recall that geoengineering projects could scorch Europe. Researchers found that "salting" clouds over the Atlantic could lead to catastrophic consequences.