Study Proposes Diamond Injection to Cool the Planet

Heist movies are rarely about solving climate change, and for good reason. It’s hard to imagine George Clooney racing down the highway with a truckload of stolen diamonds, saying, “Hey, let’s crush these sparkly gems into powder and scatter them through the stratosphere to cool the planet.”

Calculating Diamonds for Global Cooling

However, a team of researchers led by climate scientist Sandro Vattioni from ETH Zurich in Switzerland has done the calculations on which materials would be most suitable for stratospheric aerosol injection (SAI), a method of global cooling. They found that trillions of dollars’ worth of diamond nanoparticles might do the job.

Before you gather a crew for a diamond heist, remember that no one is suggesting SAI as the best way to avoid climate disaster. There are still safer, cheaper options, such as reducing fossil fuel combustion.

However, studies like this are useful to keep in our back pocket. They might help us avoid worst-case scenarios or costly mistakes. They could even lead to insights into distant exoplanet atmospheres.

For decades, scientists have considered whether injecting reflective particles into the atmosphere could provide just enough shade to counteract the warming effects of greenhouse gases.

Among the options, sulfur dioxide (SO2) has drawn a lot of attention, largely due to its presence in volcanic emissions, which has allowed researchers to study natural experiments over the years.

The Downsides of Sulfur Dioxide

While injecting millions of tons of SO2 into the atmosphere might lower global temperatures by a few degrees, the side effects could be significant. Ozone depletion, stratospheric warming, and the return of acid rain are just a few of the consequences to consider.

Now, Vattioni and his team suggest that the physical properties of sulfur particles may make them less ideal for reflecting sunlight in the first place.

By incorporating the behavior, thermodynamics, and chemistry of seven hypothetical aerosols into climate models, the researchers ranked each material based on heat absorption, reactivity, and reflectivity.

Diamonds as a Viable Alternative

An important factor often overlooked is the tendency of particles to clump together or settle when suspended in the atmosphere. Particles that settle too quickly might not reflect enough sunlight to sufficiently cool the planet. Those that clump too easily could trap heat, warming the stratosphere and altering air currents or moisture capacity.

Among the materials studied — including two types of titanium dioxide, alumina, calcite, diamond, silicon carbide, and sulfur dioxide — injecting five million tons of 150-nanometer-wide diamond particles into the atmosphere proved to be the most effective.

Not only would each diamond particle stay suspended long enough to be effective, but they also wouldn’t clump together or form toxic substances like those that contribute to acid rain.

As for sulfur particles, only rutile, a form of titanium dioxide, fared worse in terms of cooling efficiency.

The one advantage SO2 has is its cost. At around $250 per megaton, sulfur-based aerosols are much cheaper than diamond dust, which would cost about $600,000 per megaton, quickly driving the total price into the tens or hundreds of trillions.

Given the challenges of applying laboratory measurements and computer models to real-world conditions, the study’s predictions are far from certain. In fact, the findings underscore just how far we are from implementing SAI as a solution to global warming.

Which means George Clooney may need to make room in his heist van for a new accomplice with a penchant for tiny diamonds.

Read the original article on: Science Alert

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