Diamond dust injection may help reduce global warming

Injecting five million tons of diamond dust annually into the stratosphere could lower the Earth's temperature by 1.6 degrees, potentially easing global warming, according to Science.org.

Researchers were inspired by past instances where volcanic smoke and particles cooled the Earth by covering the atmosphere.

They believe diamond dust in the stratosphere could reflect sunlight and reduce heat.

In the fight against global warming, scientists explored controversial geoengineering solutions, including dumping iron into oceans and launching mirrors into space to cool the planet.

One of the proposals is a solar geoengineering method known as "stratospheric aerosol injection," which involves spraying aerosols into the stratosphere to create a cooling effect similar to a volcanic winter, to reduce the sun's effect.

- Historical volcanic eruptions caused global winters

In the past, volcanic eruptions released millions of tons of sulfur dioxide into the stratosphere, where sulfate aerosols formed through reactions with water vapor and other gases.

The aerosols reflected sunlight into space, causing volcanic winters. The most recent example was the 1991 eruption of Mount Pinatubo in the Philippines, which cooled the Earth by 0.5 degrees for several years.

Inspired by that event, scientists considered injecting sulfate aerosols into the atmosphere.

They found, however, that artificial sulfur injections could lead to sulfuric acid rain, damage the ozone layer and disrupt weather and climate patterns in the lower atmosphere.

- Research explores less harmful compounds: Calcite, diamond, aluminum

Climate scientist and postdoctoral researcher Sandro Vattioni and his team from ETH Zurich in Switzerland investigated alternative substances to sulfur dioxide.

The team wanted to find global particles that can remain in the atmosphere longer, do not trap heat by clumping and can reflect sunlight.

To achieve the result, they developed a 3D climate model that analyzes the chemistry of aerosols, their atmospheric movement and thermal responses.

In addition to sulfur dioxide, they tested seven compounds, including calcite -- the main component of limestone, diamond,and aluminum.

Each trial was conducted on a supercomputer, evaluating the effects of each compound for 45 years in real-time for more than a week.

-3D Model: Diamond dust could cool Earth by 1.6 degrees

The results indicated that diamond particles are highly effective at reflecting radiation and can remain airborne longer without clumping.

Additionally, diamonds are preferred because they do not engage in reactions that could produce acid rain, unlike sulfur.

Vattioni noted that to achieve a lasting effect, 5 million tons of diamond dust would need to be injected into the stratosphere annually, potentially cooling the planet by 1.6 degrees.

- Diamond option: $200 trillion, 2,400 times costlier than sulfur

Vattioni noted that sulfur is the second-worst option due to its tendency to absorb light at certain wavelengths, which can trap heat and disrupt climate patterns, similar to El Niño effects.

Some scientists, meanwhile, estimate that spraying diamond dust into the atmosphere annually by 2100 would require about $200 trillion, making it 2,400 times more expensive than sulfur dioxide, leading them to consider sulfur a more efficient choice.

The research was published in Geophysical Research Letters.