The Ultimate Sunblock

How to Cool the Planet: Geoengineering and the Audacious Quest to Fix Earth's Climate by Jeff Goodell Houghton Mifflin Harcourt, 272 pages, $26.00

During the 1950s, the atomic scientist Edward Teller was eager to prove that nuclear bombs could be used in construction as earthmovers, and in 1958 he won the approval of the U.S. Atomic Energy Commission for Project Chariot, a proposal to explode several multi-megaton hydrogen bombs near Point Hope, Alaska, just above the Arctic Circle. In less than two seconds, explosions equal to 160 times the power used on Hiroshima would dig a new, half-mile-long deep water harbor to help export coal.

"What objections could there possibly be to this large-scale atomic harbor-blasting project?" asked the editors of the Fairbanks Daily News-Miner. As it turned out, there could be objections. For instance, the Inupiats, who had been living on Point Hope for about 5,000 years, were less than enthusiastic. But progress is progress. "When we have the harbor we can create coal mines in the Arctic," Teller reportedly said, "and they can become coal miners."

In the end, the locals couldn't be sold on a harbor that would be iced in for nine months of the year. (Ah, NIMBYs, what can you do?) The Soviets, however, tested peaceful nuclear explosions until 1988. And Teller never lost his faith that Big Machines could win the day; he went on to champion Ronald Reagan's Star Wars missile-defense system.

Teller's ghost haunts journalist Jeff Goodell's How to Cool the Planet, an exploration of new ideas for geo-engineering, or large-scale, intentional intervention in the earth's climatic system to solve the problem of global warming. A hair-raising question hovers over these schemes: What would someone like Teller do if he had the ability and opportunity to terraform the entire planet? Would he treat all of humanity like Inupiats?

It sounds like a premise for a sci-fi short story, but in fact it's an urgent practical question. As Goodell chronicles, geo-engineering has gone from a fringe idea to mainstream discussion with astonishing speed. More scientists are getting serious about interceding directly to mitigate the worst effects if climate change gets out of hand. If they're to be believed, it won't even take very long or cost very much. We're all in Point Hope now.

A quick taxonomy is in order. Geo-engineering ideas are all over the map, and quite a few are just wacky -- say, shooting a nuke at the moon to kick up a cloud of sun-blocking dust -- but two basic ideas are being taken seriously.

The first is what the British Royal Society has termed "solar radiation management," sometimes known as "solar shielding." The idea is simple: If the earth is getting too warm, prevent some of the sun's rays from reaching it. According to the best available modeling, blocking just 2 percent of the sun's radiation would counteract a doubling of atmospheric carbon dioxide. Though there are a variety of ways to go about this -- you may have heard about space mirrors -- two have gained traction. The first and most popular involves shooting sulfur particles into the upper atmosphere to imitate the shading effect of a volcanic explosion. The particles themselves would rain out harmlessly after a few years, so the supply would have to be continually replenished with planes, blimps, or extremely long hoses. (Yes, really, hoses.) The second is brightening the tops of clouds to make them more reflective, thus deflecting more sun, which can allegedly be done by injecting them with super-fine water droplets. Unlike sulfur particles, whose effects would be global, cloud brightening would have effects on a local or regional scale.

The other frequently discussed form of geoengineering, somewhat less Dr. Evil-ish, is pulling carbon dioxide directly out of the air. One promising solution along those lines is biochar, biomass that's been pyrolized (burnt in the absence of oxygen) to form a porous charcoal that traps carbon and enriches the soil. Or there's the direct route: David Keith at the University of Calgary is building a machine that pulls carbon out by mixing air with a sodium-hydroxide spray and a bunch of other chemical processes too complicated to get into. Others have championed the idea of seeding the ocean with iron, to stimulate the growth of phytoplankton, which absorb carbon dioxide and, the theory goes, sink to the bottom of the deep ocean, thereby sequestering the carbon.

It's heady stuff, boggling in its scope and potential ramifications but almost entirely speculative. There have been few serious field experiments, so most of what's known (to use the term loosely) comes from computer modeling. Despite the fateful consequences, geoengineering remains frustratingly abstract. Readers of Goodell's journalism in Rolling Stone or his previous book Big Coal will be familiar with his gift for finding compulsively readable human stories inside weighty issues of politics and science, but even so, it's a small miracle that he's wrestled such an engaging and darkly entertaining narrative out of this topic.

Goodell's trick is to keep the focus on his cast of characters, which is surprisingly colorful. Where we might expect Dr. Strangelove, we instead find earnest, civic-minded scientists like Ken Caldeira, who spent his youth as a longhair at anti-nuke rallies and today campaigns for carbon-emissions cuts. Inevitably, there are also entrepreneurs too impatient to make a buck to wait on the science, like Russ George, who until countries started denying him port was ready to dump iron in the ocean and sell carbon credits off it. Given the world-historical consequences, it's both terrifying and fascinating that so much in geoengineering turns on the proclivities of a small number of idiosyncratic individuals.

Around the characters, however, float questions -- big questions about progress, responsibility, the future of humanity. Goodell painstakingly and judiciously elucidates these issues, but the experience is ultimately unnerving. The questions seem at once inescapable and unanswerable. I came away from the book with fewer settled opinions about geoengineering and an elevated sense of dread.

To begin with, consider that by some estimates a large-scale, controlled scientific experiment with solar radiation management could take up to 10 years. In the meantime, who controls the research? Who funds it? Who has access to the information it reveals? Will it take place behind closed doors in the Department of Defense or in public, in a transparent, open-source spirit?

If it does become possible to alter the climate by design, who decides who does it, and when, and how much? The scientists working with sulfur particles say it would take just two or three years and $10 billion per year or so to significantly alter the earth's temperature. That's relatively cheap -- not out of reach for a country, a coalition, or even a wealthy individual. If the Alliance of Small Island States -- a group of countries that might disappear beneath the waves as a result of global warming -- were to pool their resources and buy some big hoses and sulfur, what international law or treaty would stop them, and who would enforce it? Who would or could stop a powerhouse like China or the United States? The United Nations? There are echoes of nuclear negotiations here, but no precise historical analog. One way or the other, keeping geoengineering under control will mean some kind of global governance.

On a political level, what will knowledge of geoengineering do to public will to reduce carbon emissions? The dark fear of almost everyone involved is that the prospect of geoengineering will be used as an excuse to escape the difficult choices involved in revamping the world's energy, agriculture, and urban-design systems. The scientists themselves are mostly realistic about the risks and potential, but what happens when geoengineering reaches pop culture? If SuperFreakonomics is any guide, sobriety will not be the operative principle.

What happens to the law once humanity is officially in charge of the climate? Are we then liable for what takes place in it? Controlling climate, which scientists say is a simpler system than one might think, is not the same as controlling weather, which is more chaotic. But if another U.S. city is destroyed by a storm, will an angry and litigious public understand the distinction? If a geoengineering experiment goes awry, typhoon season is disrupted, and millions in Asia die from drought, what would liability even look like?

Knotty ethical issues abound. If humanity takes control of the climate, do its existing inequities become a collective moral responsibility? After all, even the pre-industrial climate was, in some sense, unfair -- some areas too hot, too arid, too wet, or too cold, life harder for some than for others. Do we try to restore an old climate or create a new one, and who decides which is better? If history is any guide, it will be the wealthy with their hands on the levers. Climate imperialism, anyone?

These issues are sufficiently complex and inscrutable that the answers may not reveal themselves until events force our hand. Several of the people interviewed by Goodell express a kind of fatalism: This stuff is going to happen one way or another, so we might as well try to learn something about it. But even learning, knowing, is its own risk, a gamble that can't be un-gambled.

Goodell ends with a hopeful image of what geoengineering could be: not a technomaniacal, Cold War–style Teller project but something done with care, transparency, respect, and even reverence -- less like blowing up hydrogen bombs under Alaska, more like organic gardening. But humans have gardened for centuries, and getting it right took some practice. If the climate garden is poorly tended, a lot more than zucchini could end up dying.