Under a White Sky: The Nature of the Future

by Elizabeth Kolbert

Once captured, CO2 has to go somewhere, and where it goes has to be secure. “The good thing about basaltic rock is it’s so easy to explain,” Wurzbacher observed. “If someone asks you, ‘Hey, but is it really safe?’ the answer is very simple: within two years it’s stone, one kilometer underground. Period.” Suitable underground storage sites aren’t rare, but they aren’t common, either, meaning that, should large-scale capture plants ever be built, they’ll either have to be located in places with the right geology or the CO2 will have to be shipped long distances.

Pulling CO2 from the air takes money. Right now, a lot of money. Climeworks charges $1,000 a ton to turn s...

Even at $100 a ton, burying a billion tons of CO2—a small percentage of the world’s annual output—would run to $100 billion.

“Maybe we are too early,” Wurzbacher mused, when I asked whether the world was prepared to pay for direct air capture. “Maybe we’re just right. Maybe we’re too late. No one knows.”

Reforestation, when combined with underground injection, yields a technique that’s become known as BECCS (pronounced “becks”), short for “bioenergy with carbon capture and storage.”

With BECCS the idea is to plant trees (or some other crop) that can pull carbon from the air. The trees are then burned to produce electricity and the resulting CO2 is captured from the smokestack and shoved underground.

For the trillion-tree project, something on the order of 3.5 million square miles of new forest would be needed. That’s an expanse of woods roughly the size of the United States, including Alaska. Take that much arable land out of production and millions could be pushed toward starvation.

As Olúfẹ́mi O. Táíwò, a professor at Georgetown, put it recently, there’s a danger of moving “two steps backward in justice for every gigaton step forward.”

The burning trash, the acres of glass, the boxes of bumblebees, the vegetables raised on chemicals and captured CO2—was it all totally cool or totally crazy? I paused for a second, then popped the tomatoes into my mouth.

In recorded history, there have been only a handful of magnitude sevens (a hundred billion cubic meters) and no eruptions of magnitude eight. Among the sevens, the most recent—and, hence, the best chronicled—is the eruption of Mount Tambora, on the Indonesian island of Sumbawa.

The premise behind solar geoengineering—or, as it’s sometimes more soothingly called, “solar radiation management”—is that if volcanoes can cool the world, people can, too. Throw a gazillion reflective particles into the stratosphere and less sunlight will reach the planet. Temperatures will stop rising—or at least not rise as much—and disaster will be averted.

Even in an age of electrified rivers and redesigned rodents, solar geoengineering is out there. It has been described as “dangerous beyond belief,” “a broad highway to hell,” “unimaginably drastic,” and also as “inevitable.”

“When I started this, I was perhaps, oddly, not as worried about it,” he observed a few minutes later. “Because the idea that geoengineering would actually happen seemed quite remote. But, over the years, as I see our lack of action on climate, I sometimes get quite anxious that this may actually happen. And I feel quite a lot of pressure from that.”

“The best possible material probably is diamond,” Keutsch told me. “Diamonds really will not absorb any energy. So this would minimize the change in stratospheric dynamics. And diamond itself is extremely unreactive. The idea that this is expensive—I don’t care about that. If we had to engineer this on a big scale because it solves a big problem, we would figure out a way to do it.” Shooting tiny diamonds into the stratosphere struck me as magical, like sprinkling the world with pixie dust.

Mathematical modeling has confirmed the mineral’s advantages, Keutsch told me. But until someone actually throws calcium carbonate into the stratosphere, it’s hard to know how much to trust the models. “There’s no other way around it,” he said.

The first government report on global warming—though the phenomenon was not yet called “global warming”—was delivered to President Lyndon Johnson in 1965. “Man is unwittingly conducting a vast geophysical experiment,” it asserted.

Carbon emissions in the 1960s were growing fast—by about five percent a year. And yet the report made no mention of reversing or even just trying to slow this growth. Instead, it advised that “the possibilities of deliberately bringing about countervailing climatic changes…be thoroughly explored.” One such possibility was “spreading very small reflecting particles over large oceanic areas.

None of the authors of the report is still alive, so it’s impossible to know why the committee jumped straight to a multimillion-dollar dump of reflective particles. Perhaps it was just the zeitgeist. In the 1960s, climate- and weather-control proposals were all the rage, both in the United States and the USSR.

In a book titled Can Man Change the Climate? an engineer named Petr Borisov suggested melting the Arctic ice cap with a dam across the Bering Strait. Hundreds of cubic miles’ worth of cold water could then, somehow or other, be pumped from the Arctic Ocean into the Bering Sea, which would draw in warmer water from the North Atlantic and, according to Borisov’s calculations, produce milder winters not just in the polar regions but also in the mid-latitudes. A rendering of the proposed dam across the Bering Strait “What mankind needs is a war against cold, rather than a ‘cold war,’ ” Borisov declared.

Man Versus Climate, a survey of this and other Soviet proposals translated into English by a Moscow-based outfit called Peace Publishers, ended with the declaration: New projects for transforming nature will be put forward every year. They will be more magnificent and more exciting, for human imagination, like human knowledge, knows no bounds.

In 1974, Mikhail Budyko, a prominent scientist at the Leningrad Geophysical Observatory, published a book titled Climatic Changes. Budyko laid out the dangers posed by rising CO2 levels but argued that their continued climb was inevitable: The only way to hold down emissions was to cut fossil-fuel use, and no nation was likely to do that.

The foresight

“In the near future, climate modification will become necessary in order to maintain current climatic conditions,” Budyko wrote. —

The best way forward, he argues, is to do everything: cut emissions, work on carbon removal, and look a lot more seriously at geoengineering.

David keith