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Book Summary: Superfreakonomics Global Cooling, Patriotic Prostitutes and Why Suicide Bombers Should Buy Life Insurance

Authors: Steven Levitt and Stephen Dubner

Substory: What do Al Gore and Mount Pinatubo have in common?

It wasn’t just the cooling potential of stratospheric sulfur dioxide that surprised Caldeira. It was how little was needed to do the job: about thirty-four gallons per minute, not much more than the amount of water that comes out of a heavy-duty garden hose.

Warming is largely a polar phenomenon, which means that high-latitude areas are four times more sensitive to climate change than the equator. By IV’s estimations, 100,000 tons of sulfur dioxide per year would effectively reverse warming in the high Arctic and reduce it in much of the Northern Hemisphere.

That may sound like a lot but, relatively speaking, it is a smidge. At least 200 million tons of sulfur dioxide already go into the atmosphere each year, roughly 25 percent from volcanoes, 25 percent from human sources like motor vehicles and coal-fired power plants, and the rest from other natural sources like sea spray.

So all that would be needed to produce a globe-changing effect is one-twentieth of 1 percent of current sulfur emissions, simply relocated to a higher point in the sky. How can this be? Myhrvold’s answer: “Leverage!”

Leverage is the secret ingredient that distinguishes physics from, say, chemistry. Think back to the Salter Sink, IV’s device for preventing hurricanes. Hurricanes are destructive because they gather up the thermal energy in the ocean’s surface and convert it into physical force, a primordial act of leverage creation. The Salter Sink ruptures that process by using wave power to continually sink the warm water all through hurricane season.

“A kilogram of sulfur dioxide, emitted by a truck or a bus or a power plant into the troposphere, does much less good for you than in the stratosphere,” Myhrvold says. “So you get a huge leverage, and that’s a pretty cool thing. That’s why Archimedes said, ‘If you give me a fulcrum, I can move the world.’”

So once you eliminate the moralism and the angst, the task of reversing global warming boils down to a straightforward engineering problem: how to get thirty-four gallons per minute of sulfur dioxide into the stratosphere?

The answer: a very long hose.

That’s what IV calls this project—a “garden hose to the sky.” Or, when they’re feeling slightly more technical, a “stratospheric shield for climate stabilization.” Considering its scientific forebear and the way it wraps the planet in a protective layer, perhaps it should be called Budyko’s Blanket.

For anyone who loves cheap and simple solutions, things don’t get much better. Here’s how it works. At a base station, sulfur would be burned into sulfur dioxide and then liquefied. “The technology for doing this is well known,” says Wood, “because early in the twentieth century, sulfur dioxide was the major refrigerant gas.”

The hose, stretching from the base station into the stratosphere, would be about eighteen miles long but extremely light. “The diameter is just a couple inches, not some giant-ass pipe,” says Myhrvold. “It’s literally a specialized fire hose.”

The hose would be suspended from a series of high-strength, helium-filled balloons fastened to the hose at 100-to 300-yard intervals (a “string of pearls,” IV calls it), ranging in diameter from 25 feet near the ground to 100 feet near the top.

The liquefied sulfur dioxide would be sent skyward by a series of pumps, affixed to the hose at every 100 yards. These too would be relatively light, about forty-five pounds each—“smaller than the pumps in my swimming pool,” Myhrvold says. There are several advantages to using many small pumps rather than one monster pump at the base station: a big ground pump would create more pressure, which, in turn, would require a far heavier hose; even if a few of the small pumps failed, the mission itself wouldn’t; and using small, standardized units would keep costs down.

At the end of the hose, a cluster of nozzles would spritz the stratosphere with a fine mist of colorless liquid sulfur dioxide.

Thanks to stratospheric winds that typically reach one hundred miles per hour, the spritz would wrap around the earth in roughly ten days’ time. That’s how long it would take to create Budyko’s Blanket. Because stratospheric air naturally spirals toward the poles, and because the arctic regions are more vulnerable to global warming, it makes sense to spray the sulfur aerosol at high latitude—with perhaps one hose in the Southern Hemisphere and another in the Northern.

Myhrvold, in his recent travels, happened upon one potentially perfect site. Along with Bill Gates and Warren Buffett, he was taking a whirlwind educational tour of various energy producers—a nuclear plant, a wind farm, and so on. One of their destinations was the Athabasca Oil Sands in northern Alberta, Canada.

Billions of barrels of petroleum can be found there, but it is heavy, mucky crude. Rather than lying in a liquid pool beneath the earth’s crust, it is mixed in, like molasses, with the surface dirt. In Athabasca you don’t drill for oil; you mine it, scooping up gigantic shovels of earth and then separating the oil from its waste components.

One of the most plentiful waste components is sulfur, which commands such a low price that oil companies simply stockpile it. “There were big yellow mountains of it, like a hundred meters high by a thousand meters wide!” says Myhrvold. “And they stair-step them, like a Mexican pyramid. So you could put one little pumping facility up there, and with one corner of one of those sulfur mountains, you could solve the whole global warming problem for the Northern Hemisphere.”

It is interesting to think what might have happened if Myhrvold was around one hundred years ago, when New York and other cities were choking on horse manure. One wonders if, while everyone else looked at the mountains of dung and saw calamity, he might have seen opportunity.

On balance, Budyko’s Blanket is a fiendishly simple plan. Considering the complexity of climate in general and how much we don’t know, it probably makes sense to start small. With the fire-hose approach, you could begin with a trickle of sulfur and monitor the results. The amount could be easily dialed up or down—or, if need be, turned off. There is nothing permanent or irreversible about the process.

And it would be startlingly cheap. IV estimates the “Save the Arctic” plan could be set up in just two years at a cost of roughly $20 million, with an annual operating cost of about $10 million. If cooling the poles alone proved insufficient, IV has drawn up a “Save the Planet” version, with five worldwide base stations instead of two, and three hoses at each site. This would put about three to five times the amount of sulfur dioxide into the stratosphere. Even so, that would still represent less than 1 percent of current worldwide sulfur emissions. IV estimates this plan could be up and running in about three years, with a startup cost of $150 million and annual operating costs of $100 million.

So Budyko’s Blanket could effectively reverse global warming at a total cost of $250 million. Compared with the $1.2 trillion that Nicholas Stern proposes spending each year to attack the problem, IV’s idea is, well, practically free. It would cost $50 million less to stop global warming than what Al Gore’s foundation is paying just to increase public awareness about global warming.

And there lies the key to the question we asked at the beginning of this chapter: What do Al Gore and Mount Pinatubo have in common? The answer is that Gore and Pinatubo both suggest a way to cool the planet, albeit with methods whose cost-effectiveness are a universe apart.