To stop global warming we may need to start thinking outside the box
In the summer of 1858, a putrid odor of raw sewage arose from the River Thames in London and choked the city in its sickly grip. The Great Stink, as it came to be known, spurred Britain's lawmakers to rush a bill through Parliament to provide the money to build a modern sewer system -- one that would discharge sewage downstream from the river's drinking water intake. Construction of similar structures in the same era in a number of European and American cities, including Paris and Chicago, ended epidemics of typhoid and cholera, which victims contracted by drinking water contaminated with feces. If the Victorians could eliminate these diseases through careful disposal of human waste, why can't we counter climate change by extracting carbon dioxide from the atmosphere and burying it where it can do us no harm?
That radical proposal lies at the core of Fixing Climate, the latest in a spate of books on the seemingly intractable problem of global warming. While most writers stress the need to cut greenhouse gas emissions, the authors of Fixing Climate -- Columbia University earth scientist Wallace Broecker and the science writer Robert Kunzig -- suggest instead that we view carbon dioxide as a form of sewage: a pollutant with which we have carelessly contaminated the atmosphere, but one that we can remove with the right technology. Doing so is necessary, they argue, because the chance that we will succeed in paring back our carbon emissions with the speed required to avert disaster is quite small.
Broecker and Kunzig embrace a techno-fix that would require us to scrub our carbon dioxide waste from the atmosphere and sock it away in rocks. Their proposal is typically American: upbeat in its can-do spirit, yet pragmatic. The pair are not breast-beating penitents. In fact, they open their book with an eloquent ode to the beauty of the piston engine, acknowledging that fossil fuels have enabled the average American to live as well as a preindustrial king. Yet it's time to shovel away the scum. "We need to create the means for taking our carbon back out of the air and putting it underground, where it came from," they write.
If anyone should be taken seriously on the topic of climate change, it is Wallace Broecker, who has spent more than 50 years studying the climate of the past 200,000 years, and who was one of the first to warn, more than three decades ago, of the dangers of global warming. Born in 1931 ("the same year as Twinkies," the book points out), he arrived in 1952 at what is now Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York. He has spent his entire career there, publishing more than 400 papers and winning numerous prizes, including the National Medal of Science. Over the years, Broecker has developed ways to calculate the rate of gas exchange between the atmosphere and the ocean -- in particular, oceanic uptake of carbon dioxide -- and devised what is known as Broecker's Conveyor Belt, a global scheme of ocean circulation that is thought to drive climate patterns the world over.
As background to their proposal, Broecker and Kunzig devote about a third of their book to explaining the complex history of climate change science; a laudable effort, though at times my eyelids did begin to droop. To their credit, they enliven the text with asides on the notable figures who first figured out the science at hand (among them the Swedish physicist Svante Arrhenius, whose "ravishing young wife, Sophia" deserted him in 1894 after a year of marriage in the midst of his calculations on planet-warming carbon dioxide).
The book's real focus, though, is a climate fix hatched by Klaus Lackner, now a physicist at the Earth Institute at Columbia University. Lackner's company, Global Research Technologies, announced in the spring of 2007 that it had built a prototype "air-capture technology product" to suck CO2 out of the atmosphere. When Broecker first heard Lackner talking about his ideas in 1999, he recalled thinking, "This guy is nuts." Lackner, then an associate director of Los Alamos National Laboratory, argued that we should attempt to accelerate the natural chemical breakdown of rocks. The plan: grind up billions of tons of magnesium- or calcium-rich rocks, chemically combine them with carbon dioxide to form another type of rock -- a harmless carbonate -- and then find a place to put the resulting mountains of the stuff. Later on, Broecker found Lackner's tendency to think big-and his willingness to attack a problem from first principles -- "more exciting than crazy," and lured him to Columbia.
In fact, there is nothing all that revolutionary about pulling carbon dioxide out of the air; it is done on every space shuttle and submarine to prevent crews from asphyxiating on their own exhaled breath. Lackner built his prototype on a budget of $5 million from the late Gary Comer, the founder of Lands' End. In this device, crushed rocks have been replaced by a plastic compound that reacts with CO2 to form sodium bicarbonate: essentially, baking soda. If Lackner's vision comes to fruition, 20-foot-tall carbon-sucking towers-each resembling an erect Tower of Pisa-could be arrayed all over the planet. The final step in this massive cleanup project would be to extract CO2 from the bicarbonate and inject it into the ground in liquid form.
Each tower would extract about one ton of carbon dioxide a day, so it would take an awful lot of towers to scrub the 80 million tons we emit daily. The sheer scale of the problem dwarfs any single solution, but in Broecker and Kunzig's view, Lackner's invention is "the only hope." Their reasoning is simple: the towers can be placed anywhere -- far easier and more practical than attaching a CO2 scrubber to every car and airplane on the planet. And because CO2 disperses quickly through the entire atmosphere, removing it in one spot helps the whole world.
By contrast, say Broecker and Kunzig, collecting CO2 from the flues of power plants would entail transporting the gas perhaps hundreds of miles to a dumping ground. Nevertheless, this too promises to be an important means for steering us from the path of doom, should we manage to make it happen. In January, the Department of Energy scrapped plans for FutureGen, a coal-fired plant that was to collect and dispose of its own CO2 emissions.
The Norwegian oil company Statoil currently captures CO2 from its drilling operations at the Sleipner natural gas field in the North Sea, and it then injects a million tons of the gas each year under the seabed. There are plenty of other places to put the heat-trapping gas. Iceland, for example, is made entirely of basalt, a volcanic rock rich in calcium silicates, which bind with CO2. This fall, Reykjavik Energy plans to begin pumping carbon dioxide half a mile deep into basalt deposits. Vast banks of basalt also exist elsewhere: in the United States, volcanic rock covers more than 60,000 square miles of Washington, Idaho, and Oregon.
Detractors will inevitably dub such schemes misguided or deluded. Tim Flannery, for one, argues in his 2005 book, The Weather Makers, that the volume of carbon dioxide we create is "so prodigious that it seems impossible for Earth to tuck it away without suffering fatal indigestion." The authors of Fixing Climate are not oblivious to the scale of the problem or the expense of the solution. If we choose Lackner's original proposal, then large mounds of carbonate must be piled or buried somewhere. That would transform the landscape, but so would covering hundreds of square miles with solar panels. "There is no free lunch in solving the CO2 problem," Broecker and Kunzig say.
As for Lackner's current proposal to array carbon-capturing towers across the globe, they admit that it sounds utopian. "If the amount [of CO2] the world produced in a single year were spread over Manhattan, it would rise three-quarters of the way up the Empire State Building. On the other hand, if all the wastewater produced in the United States alone were spread over Manhattan, even the radio antenna on top of the Empire State would be far beneath the waves. Yet somehow in the twentieth century we managed to get our sewage problem under control." With our own Great Stink now threatening to overpower the entire planet, we owe it to ourselves and our descendants to consider the merits of such ambitious technological fixes before we suffocate in our own stifling waste.
