Published 28 June 2010 by Ashutosh Jogalekar

Paul Crutzen’s Other Big Idea

Nobel Laureate Paul Crutzen will be at Lindau this year, along with his fellow recipient F. Sherwood Rowland. The two along with Mario Molina contributed to one of the most significant intersections of science with politics and public policy in the twentieth century when they discovered the effects of chlorofluorocarbons and other chemical compounds on the all-important ozone layer. Crutzen is well-known for that contribution.

What Crutzen is not that well-known for may perhaps make him even more famous after a few years. In 2006, Crutzen published an article in the journal Climate Change that proposed a cheap and audacious-sounding technological fix to ameliorate the harm done by global warming. He proposed releasing millions of tons of sulfate and sulfur dioxide particles into the upper atmosphere which would cool the earth by reflecting sunlight. His scheme is part of what is now called ‘geoengineering’- willfully changing the climate of our planet to counteract the harmful effects of global warming. If Crutzen talks about geoengineering this year at Lindau, it will very likely be one of the most provocative talks at the meeting, and students should make sure they ask him lots of questions about it.

Let’s admit it. If we want to talk about the craziest-sounding ideas dreamt up by mad scientists with disheveled hair and demented glints in their eyes, geoengineering would admirably fit the bill. This is the stuff that pulpy science fiction is made of, when horrible accidents engineered by technology-obsessed scientists cast humanity into eternal doom. Yet, geoengineering is now seriously being considered by top scientists and policy makers. It also has a long history that is permeated by some of the most brilliant minds of the twentieth century. Science fiction it may sound like, but it’s being treated as serious science by serious people. Some have predicted that the issue of geoengineering will be catapulted in a few years into one of the most visible public debates of our times, regularly bandied about in the mainstream media. It will become a topic rich with scientific, political, social and moral dilemmas. Given the potential impact and importance it can have, I personally feel very likely that this will happen.

So what is geoengineering? It is simply the application of technology to engineer our environment to our benefit. If this does not sound like a novel definition, it probably isn’t. Human beings have been changing their environment using technology for thousands of years. The invention of agriculture and architecture and the breeding and domestication of animals are all examples of engineering our surroundings to suit our needs. Yet the word geoengineering deserves a modern definition in its own right simply because of the magnitude and audacity of ideas it dares to conjure up. Crutzen’s sulfur dioxide scheme constitutes one of them. Not bold enough? How about building giant hoses that will release sulfates tens of kilometers high up? Still too boring? How about dropping billions of tons of iron compounds into the world’s oceans to encourage the growth of CO2-eating algae? Covering the oceans up with gigantic white plastic sheets to reflect sunlight? And these seem to be some of the more conservative ideas floating around. One of the main problems that people seem to have with geoengineering schemes is that they think these schemes will add another dangerous and uncertain variable to a game we have already played with our planet beyond reason. And yet if we think about it, playing with the earth does not sound so bad when we ponder our present situation and its consequences.

Let’s take a hard look at the facts. Mankind has warmed the planet by emitting carbon dioxide and other greenhouse gases on an unprecedented scale. This contribution has already engineered the planet in its own way by radically changing the environment and making the future uncertain for further generations. Drastically reducing CO2 emissions seems to be the one way to possibly stall the impact, even if we probably cannot completely neutralize it. But human nature being what it is, it has proven immensely difficult to adopt global policies that would reduce emissions. Kyoto was a dismal failure. Last year at Lindau, Rajendra Pachauri who is the chairman of the IPCC was glowingly optimistic about the 2009 Copenhagen conference. Now we know that although there were weak assurances and promises, that meeting too ended in failure. The bottom line is, the world still runs on fossil fuels, and many think it’s going to be decades if not more before all the inequities and differences among the peoples of our planet will make it possible to approach anything comprising significant consensus in reducing fossil fuel emissions. Clearly it’s a Sisyphean task to convince humans to give up their ambitiously high standards of living. Till then it could be too late.

But if human beings find it hard to reach a consensus, they don’t find it that hard to come up with other creative ideas to address the key issues. If we could modify the weather by other means and buy ourselves some time at the very least, shouldn’t we do it? The twentieth century is replete with attempts by scientists to come up with ways to change the climate for a variety of reasons, far before global warming was ever on the agenda. Probably the most high profile reason was being able to influence local weather patterns as a form of warfare; if you could radically engineer the weather around enemy formations, you could throw all their war preparations into chaos. Such type of thinking pervaded Cold War strategy. And it got a boost from one of the most brilliant humans being who ever lived.

John von Neumann, mathematical wizard who could multiply six-digit numbers in his head and recite the entire telephone book when he was six years old in his native Hungary, has become an anecdote-generating legend. Almost any anecdote about this great man and the quickness of his mind is likely to be familiar or sound like a cliché, so I will refrain. The sheer diversity of fields- pure mathematics, physics, nuclear weapons design, economics, computing, biology- to which he made lasting contributions boggles the mind and is without a doubt unprecedented. He made so many important contributions to so many important fields that even now one suspects if there was a conspiracy of geniuses who all published papers and ideas under the same name. In only one lifetime, while establishing the mathematical foundations of quantum theory, inventing game theory, designing the plutonium implosion bomb, laying out the blueprint for genetic replication, exploring the workings of the brain and becoming a father of computer science through his invention of what we call ‘software’, von Neumann ended up contemplating the use of the computer for weather prediction almost as a pastime. A prized consultant to top-secret government agencies, von Neumann had grandiose schemes for first predicting and then manipulating the weather using intensive computer modeling. Although his diabolical schemes to wage war (probably fortunately) did not come to pass, von Neumann’s ideas were the forerunner for some of the earliest computer models of climate, culminating in the sophisticated General Circulation Models (GCMs) that modern day climate scientists use.

Von Neumann died in 1957 in great pain from cancer, heavily surrounded by military security personnel in fear that he may divulge nuclear secrets while medicated. As if one brilliant Hungarian was not enough, another brilliant Hungarian materialized to don von Neumann’s mantle.

Nobody looms as large over geoengineering as the brilliant and impetuous Edward Teller, the ‘father of the hydrogen bomb’. Teller was so obsessed with nuclear weapons that he has become almost a clichéd caricature of the mad scientist, supposed to be one of the inspirations for the character of Dr. Strangelove in Stanley Kubrick’s famous nuclear satire. As the greatest nuclear weaponeer in history, Teller never shied away from making nuclear bombs bigger, better, smaller and more powerful. Throughout his life Teller was known for two things, his scientific brilliance and his tortured relationship with his fellow scientists. After his testimony in the trial of Robert Oppenheimer made him a virtual outcast from the scientific community, Teller began to hobnob with powerful military and political leaders who wanted bigger and better nuclear weapons. Teller’s love for nuclear weapons led him in the fifties to propose ‘Project Plowshare’. Project Plowshare figures big in the history of geoengineering. It was literally a plan for sculpting the earth to suit human needs. It envisaged everything from blasting gigantic harbors in seconds to diverting the course of entire rivers to turn deserts into lush grasslands, all made possible by megaton nuclear bombs. Such grand planning was typical of the Cold War belief in technology, a belief which lasts even today. The Soviets also explored such plans and publicized them as glorious Communist dreams intended to bring the benefits of technology to the masses. Nuclear weapons had acquired a bad rap because of their destructive effects. Now Teller wanted to put a positive spin on them. But Teller’s motives were not completely benevolent. If Project Plowshare became popular, it would lead to more nuclear testing and hence to more nuclear building, both of which were Teller’s cherished goals.

Edward Teller (1908-2003)

One of the first experimental projects that Project Plowshare had in mind was excavating a giant harbor in what was considered a remote region of Alaska. In just a few weeks Teller was transformed into a marketing executive who strove hard to convince the local population including the local Inuit natives about how nice such a harbor excavated by a huge nuclear blast in two seconds would be for them. He even said he could sculpt a harbor in the shape of a polar bear. Teller insisted that fallout, which was the biggest threat from nuclear detonations, would be limited. He did not really give much thought to the details of the region and the fact that the Soviet Union was only 180 miles from the harbor’s location. Fortunately, Teller’s plan was killed in the water when a geologist named Don Foote mapped the entire region and its rich biodiversity and showed that not only would the livelihood of the Inuits be completely destroyed, but that uncertainty in wind patterns would likely draft the radioactive fallout toward the Soviet Union, a geopolitical disaster. A disgruntled Teller still did not give up on his dreams of changing the face of the planet, and planned for a small experiment in the Nevada desert that would perhaps convince the naysayers. The goal was quite elemental, to see how big a hole a nuclear weapon would dig. In 1962, a 1.5-megaton bomb excavated a crater more than a thousand feet in diameter and 300 feet in depth in about two seconds. Unfortunately, fallout from the blast was carried by the wind as far as Canada. Finally, after more than a decade and hundreds of millions of dollars in spending, Project Plowshare was dead. The crater still exists and is a tourist attraction.

But Teller’s highly fertile mind never remained still. Throughout his life he kept on coming up with highly creative and more than a little wacky ideas of accomplishing technological feats using nuclear weapons. I think Teller’s whole frame of mind is aptly summed up by Carl Sagan, who said that Teller’s problem was that he genuinely liked nuclear weapons. Thus he wanted to use them for almost any problem. Want to turn coal into diamonds? Use the pressure from a nuclear blast. Teller even insisted using nuclear weapons for pure science research. Want to analyze moon dust? Explode a nuke on the moon and analyze the resulting spectrum. Until his death in 2003 at the ripe old age of 95, Edward Teller continued to be enamored of technology as the solution to mankind’s greatest problems. His vision, even if it has been transformed into something a little more gentle and realistic, still lives on in the minds of geoengineers.

So who are these people and what do they want to do? Geoengineering schemes seem to fall into two categories. We know the first one as ‘carbon sequestration’ and it sounds more benign. It seeks simply to suck the excess CO2 out of the air and store it in one form or the other, either underground or in other locations. However, the word ‘simply’ does not do justice to the complexity of the problem. CO2 is a high-entropy material that has been generated from low-entropy fossil fuels such as coal. Essentially reverting the process might require much more energy than is saved. Plus, where is this energy going to come from? From fossil fuels which are going to release more CO2 themselves? That would be futile. So scientists are trying to come up with other creative ideas. One of the more creative ideas is being tested by David Keith, a physicist at the University of Calgary. Keith’s process to trap CO2 relies on high-school chemistry. Lye or sodium hydroxide will react with the CO2 from air to form sodium carbonate. This in turn will react with calcium oxide to form calcium carbonate. In his lab Keith is running experimental CO2 absorption columns. Success until now has been spotty; the reduction in CO2 is typically only 5 ppm, but the technology is worth exploring.

The second category of proposals would make science fiction fans stand up, because these are the ones aimed at actually modifying the planet’s atmosphere in one way or the other. Crutzen’s proposal to inject sulfur dioxide particles in the stratosphere is a running candidate. One reason why it is taken seriously is because there is a precedent in which the earth actually geoengineered itself. In 1991, the volcano Mount Pinatubo in the Philippines erupted and put millions of tons of sulfur dioxide particles in the atmosphere. True to calculations and predictions, the planet actually cooled by a fraction of a degree. The most likely location for doing this kind of cooling experiment is the Arctic, which is rapidly losing ice. The problem with ice is that it constitutes positive feedback which makes the global warming problem worse; less ice means less reflection of sunlight which means higher temperatures which means even less ice and so on. Consequently, cooling the atmosphere above the arctic would mean more ice, which would kick-start the reverse cycle, increasing reflectivity and cooling the planet further. The amount of sulfur dioxide needed and its cost is not too much compared to what’s at stake. The main problem that some people see with this scenario is that it’s a band-aid, since it won’t actually curb CO2 emissions. Also, CO2 doesn’t just cause global warming. It also causes other serious problems like ocean acidification, which is killing off entire species and catastrophically disturbing ocean biodiversity and balance. Sulfur in the atmosphere is not going to mitigate these other issues. The good thing though might be that these increasing CO2 levels would be absorbed by plants, encouraging foliage which will suck up even more CO2. This brings us to the other geoengineering scheme- seeding the oceans with iron compounds. These compounds will encourage the growth of algae which will eat up the excess CO2. Algae might also serve another purpose. The British scientist James Lovelock who is the originator of the “Gaia” theory pointed out that algae produce the gas dimethyl sulfide (if you haven’t smelt this, don’t, as I can attest from experience) which also forms sunlight-reflecting aerosols. Lovelock is a big fan of engineering and thinks that it’s too late now for us to get a grip on climate change by reducing emissions alone.

Probably the craziest-sounding idea for geoengineering has been suggested by University of Arizona scientist Roger Angel. Angel proposes shooting out thin polymer-based disks, each about the size of a trash can lid, into orbit around earth. Once in orbit, these disks will cast a huge shadow on earth that will reduce sunlight absorption by about 2%. Even this small change will be enough to cool the planet. The problem? The mind-boggling number of disks that would have to be shot out into space- about 16 trillion. But Angel’s proposal is one of a kind proposed by scientists that include launching millions of sunlight-reflecting mirrors into orbit, essentially serving the same purpose.


Then there are proposals grounded in genetic engineering. These are again being taken seriously by a number of well-known scientists. Craig Venter, the famous genome pioneer who recently synthesized a working organism from scratch, is on the lookout for CO2-eating bacteria. Freeman Dyson has suggested a slightly more futuristic idea- engineering trees with silicon leaves instead of carbon leaves which would absorb much more CO2.

Science fiction or not, mainstream scientists are wary of all such proposals for a variety of reasons. Chief among them is the belief that such proposals will be eagerly seized upon by industrial interests who can then go on emitting CO2 with abandon. Geoengineering is seen by these opponents as nothing more than a band-aid, leaving us free to indulge in even more fossil fuel based development. There is definitely merit to this point of view, but the same opponents should also realize that we are probably going to be entrenched in fossil fuel based development for decades. Till then we must do something to explore alternative scenarios for cooling the planet. There are arguments which say that geoengineering messes with a complex system about which we understand very little, and these are not invalid. But the history of technology shows that for whatever reason, we have been able to manage complex systems much better than what we initially imagined. Geoengineering should be supported at least on an experimental scale. The other more philosophical problem that some have with these ideas is that they cast yet another volley in mankind’s attempts to destroy the world’s natural essence. But whether we like it or not, we have already destroyed and irrevocably altered this essence since the last 40,000 years or so, when modern humans started migrating across the earth in large numbers. The planet now is radically different from what it was then, and it’s hard to see how geoengineering would be any different from the massive amounts of engineering we have done on this planet until now. And the bottom line is that global warming is too complex a problem to be attacked only through a single line of inquiry, that of reducing CO2 emissions. Only a multipronged approach can help resolve such a convoluted dilemma.

But ultimately the objection to geoengineering goes much deeper than technical and scientific issues. Geoengineering seems to signal the epitome of the hubris that human beings have always had, fuelling the belief that technology is going to solve all our problems. To some extent it has gotten a bad name because of scientists like Edward teller who wanted to harness the primeval force of the atom for sculpting our environment, without much thought about consequences. We all know what happened when Icarus became giddy with his powers of flight and soared too close to the sun. Our own Icarus has already outdone himself in his ambitions. Geoengineering seems only to be the culmination of our fantasy to achieve mastery over the planet. A planet with geoengineering will very likely look disturbingly artificial, with abnormally high levels of CO2 being sustained in a delicate balance with a sulfate-laden atmosphere, algal blooms in the ocean, an armor of mirrors in outer space, and landscapes dotted with CO2-eating plants with silicon leaves and behemoth CO2-sucking machines. All will look nice and cozy, until the very delicate balance is inevitable perturbed by our ignorance of complexity.

As the old proverb says, we need to be careful about what we wish for. Our wishes might come true.

Ashutosh Jogalekar

Ashutosh Jogalekar is a scientist and science writer based in Boston, USA. He has been blogging at the “Curious Wavefunction” blog for more than ten years, and in this capacity has written for several organizations including Scientific American and the Lindau Nobel Laureate Meetings. His literary interests specifically lie in the history and philosophy of science.