In order to cool the Earth, scientists have long proposed sawing aerosols in the upper atmosphere to reflect light back into space. Now they have suggested that the best material for this might be diamond dust.
Climate change on Earth and its irreversibility
A multi-institutional team of climatologists, meteorologists and Earth scientists has found evidence that dumping diamond dust from an airplane into the atmosphere could cool the planet. In their study, published in the journal Geophysical Research Letters, the team used 3D climate models to compare aerosols that could be used to cool the planet.
Previous studies have shown that the Earth is at a critical juncture — a warming planet has led to changes in global weather patterns that can only get worse as the planet warms. If this is true, then some people argue that the only solution at this point is to quickly find a way to cool the planet. Some scientists propose deploying millions of devices that extract carbon from the air, which could then be sequestered.
The problem is that if we’ve reached the critical juncture, removing carbon won’t help – we have to find a way to not just reduce warming, but to actively cool the planet. The only way to do this, according to most experts, is to spray aerosols into the atmosphere to reflect sunlight and heat back into space.
Artificial cooling of the planet
The main candidate for this is now sulfur dioxide. Since it is naturally ejected into the atmosphere by volcanoes, scientists have a pretty good idea of what would happen if humans started injecting it artificially. The disadvantage is that it could cause acid rain around the world. It could also damage the ozone layer and probably disrupt weather patterns in the lower atmosphere.
In this new study, researchers wondered which material would be best suited as a cooling medium for the planet. In an effort to get a clue, they built a 3D climate model that showed the impact of adding aerosols to the atmosphere. The software also included the impacts of different aerosols, such as the reflection of light and heat, how the aerosols would eventually settle to the ground, and whether they would stick together in the atmosphere, retaining more heat.
The research team then modeled the impact on Earth of injections of seven candidates: calcite, diamond, aluminum, silicon carbide, anatase, rutile, and sulfur dioxide. It showed that diamond dust would be the best choice — the particles would reflect more light and heat, they would stay in the air for a reasonable period of time, and they would not be prone to sticking together. The researchers note that since diamond dust is chemically inert, it is unlikely to react to form acid rain.
The model suggests that injecting 5 million tons of synthetic diamond dust into the atmosphere per year could cool the Earth by 1.6°C in 45 years. The downside, of course, would be the enormous cost — about $200 trillion dollars.
According to phys.org
