There is a plan B to reverse global warming by shooting diamonds. But it costs more than $200 billion.

Despite all global efforts, greenhouse gas emissions continue to rise. What will we do if everything fails? Could we go back if temperatures rise above the 1.5°C limit set by the Paris Agreement? In Switzerland, a group of scientists believe that Plan B is solar geoengineering. And diamond dust is our ace in the hole for cooling the planet.

A glamorous proposal. Researchers from ETH Zürich propose releasing millions of tons of diamond dust into the stratosphere as a temporary solution to global warming.

According to calculations published in the journal Geophysical Research Letters, emissions of five million tons of diamond dust each year would reflect enough sunlight to reduce global temperatures by 1.6°C over 45 years, mitigating the worst impacts of climate change.

Volcanic inspiration. This method simulates the cooling effect of the most powerful volcanic eruptions in history. When a volcano releases sulfur dioxide into the atmosphere, it creates aerosols that reflect sunlight. If this happens in large numbers, the eruption will temporarily lower temperatures across the planet.

But unlike sulfur dioxide, diamond dust is chemically inert and does not damage the ozone layer or cause acid rain. In addition, its optical properties are ideal for reflecting sunlight.

Economic challenge. Then there is the question of price. The estimated cost of maintaining this initiative until the end of the century, scientists have calculated, is more than $200 trillion (ten times the GDP of the United States or China), which represents a significant obstacle to its implementation.

And yes, the research always applies to synthetic diamonds. Although the company is also exploring more common and easier-to-manufacture materials such as calcite and alumina, which could offer similar benefits on a smaller budget.

A desperate measure. Like a hammer behind glass that says “break in case of emergency,” the authors see their own idea as a lifeline if net-zero emissions commitments, renewable energy facilities and carbon capture technologies are not advanced enough to stop global warming.

While models show promise, releasing millions of tons of diamond dust into the atmosphere could have long-term environmental consequences that scientists and their models have missed. However, the authors argue that more research is needed to assess the feasibility and environmental impacts of geoengineering against climate change.

Image | woodleywonderworks (Flickr, CC BY 2.0)

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