Should We Dim the Skies to Save the World?

The podcast Crazy/Genius returns with the story of a volcano, a toxic cloud, and a radical solution to humanity’s most important problem.

Mount Raung, a volcano in Indonesia, erupts at night.
Volcanic eruptions, like Mount Raung in Indonesia, spray the skies with sulfuric particles that partially block solar radiation. Some climate scientists see it as an inspiration for a bold, if risky, plan to slow global warming. (Antara Foto Agency / Reuters)

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A fleet of jets takes off from airports around the world. They ascend beyond the cruising altitude of commercial airlines until they reach the stratosphere. Then, they spray. A thick stream of sulfuric acid pours forth from the aircraft, bathing the skies in toxic aerosols. Winds spread the noxious cloud around the world, where it lingers for months, even years. The effects down on Earth are unmistakable. On every continent, blue skies are replaced with a pallid veil of white. The Milky Way disappears. There is less sunlight for solar power, more damage to the ozone, and a surge of droughts across southeastern Asia and central Africa.

Also, the Earth cools.

This scene is not an ongoing government conspiracy, or an unreleased prelude to The Matrix, or a diabolical plot by C. Montgomery Burns. It’s a plan that some of the world’s most sober climate experts have earnestly considered. It’s called solar geo-engineering, or, more euphemistically, solar-radiation management. And while we might be years from serious people screaming that it’s something we must do, some scientists today insist that it’s something we must research—in the bleak but plausible scenario that this is the emergency switch humanity will someday have to pull.

In Season Two of the podcast Crazy/Genius, we’re exploring five radical ideas to save the world. Solar geo-engineering has a rather unique combination of radicalness and world-saving potential. So, in our first episode, produced by Kasia Mychajlowycz and Patricia Yacob, we dive deep into its origins in volcanology and explain its clear benefits and myriad risks to humanity.

Today, the global political community is united, not in its ability to combat climate change, but rather in its incapacity to act in ways that will reverse it. In the words of my colleague Robinson Meyer, who appears in the episode: “This kind of failure, writ large, would devastate Earth in the century to come.”

Dimming the skies to save the world might sound like an absurdity, a slice of science fiction. But doing nothing sounds just as dystopian. Thus, solar geo-engineering is a question of proportional risk. In sports, it often behooves the underdog to use high-risk strategies when victory seems unlikely. It’s why desperate hockey teams are well advised to pull the goalie, and why trailing football teams stop punting to the opponent and “go for it” on fourth downs.

Nobody knows for sure how much time humanity has until global warming makes the planet unlivable for large numbers of people. What’s clearer is that such a moment in history is not only thinkable but also, without dramatic technological or political changes, approaching. The scientists I spoke to aren’t frantically yelling, “Pull the goalie!” They’re saying something more like this: It’s getting late in the game, and if we must do the unthinkable, let’s understand the risks—lest we fail to act before all is lost.