Realization 5. Some forms of geoengineering, expensive as they are, may be a hundred to a thousand times cheaper than building Renewistan, and some of them would have an instantaneous effect on climate rather than one delayed by decades. As soon as climatic conditions become frightening and urgent, geoengineering schemes will suddenly jump from “plausible but dangerous” to “dangerous but we have no choice.” The cost is low enough that a single nation or even a wealthy individual could set in motion a geoengineering project that would affect everyone on Earth. (A growing number of work-shops are addressing the specter of unilateral geoengineering.)
• Any one of those realizations is sufficient; in combination they are overwhelming. Geoengineering schemes will be in high demand shortly, but what exactly is on offer? Here’s the catalog as of 2009, in order of the likelihood of their being attempted, with the most tempting first: global dimming with stratospheric sulfates, brightening the Earth with clouds from ocean spray, feeding iron to ocean phytoplankton to increase their fixation of carbon, floating vertical pipes in the ocean for the same purpose, converting agricultural waste into biochar, massive air capture of atmospheric carbon, and global dimming with mirrors in space. No doubt more ideas will emerge—and should emerge; that’s a paltry list, considering the potential need. But examining these will give a sense of the ingenuity, daunting scale, and potential hazards of geoengineering strategies.
Employing stratospheric sulfates is the first choice of most climatologists because it has already been proven to work. In 1991 a volcano in the Philippines, Mount Pinatubo, erupted explosively, sending 20 million tons of sulfur dioxide twenty miles up into the stratosphere, where the material oxidized into tiny sulfate droplets that absorbed and reflected sunlight. The following year, the entire planet cooled by half a degree Celsius. Sea ice in the Arctic was so durable that the crop of particularly large and healthy young polar bears born in 1992 were called the Pinatubo cubs.
In 1998, at a climate conference in Aspen, a space weapons expert (and microreactor designer) named Lowell Wood gave a provocative presentation on the stratospheric-sulfates scheme. Climate modeler Ken Caldeira was so annoyed that he set out to prove the idea couldn’t work; instead his models suggested it might work very well, with relatively few side effects. Caldeira became a convert to geoengineering and began cowriting papers with Wood. In 2006 Paul Crutzen published an essay in Climatic Change that signaled a major shift in scientific opinion. He found international efforts to reduce carbon dioxide emissions so “grossly disappointing” that a backup plan such as “albedo enhancement by stratospheric sulfur injections” must be explored. He wrote:If sizeable reductions in greenhouse gas emissions will not happen and temperatures rise rapidly, then climatic engineering, such as presented here, is the only option available to rapidly reduce temperature rises and counteract other climatic effects. Such a modification could also be stopped on short notice, if undesirable and unforeseen side effects become apparent, which would allow the atmosphere to return to its prior state within a few years. . . . Provided the technology to carry out the stratospheric injection experiment is in place, as an escape route against strongly increasing temperatures, the albedo adjustment scheme can become effective at rather short notice, for instance if climate heats up by more than 2°C globally or when the rates of temperatures increase by more than 0.2°C/decade.
Proposed methods of delivering the sulfur to the stratosphere include airplanes, cannons, and balloon-suspended hoses. One or two million tons of sulfur a year could keep the Earth’s temperature level even if greenhouse-gas emissions doubled. As Ken Caldeira put it, “If we could pour a five-gallon bucket’s worth of sulfate particles per second into the stratosphere, it might be enough to keep the Earth from warming for fifty years. Tossing twice as much up there could protect us into the next century.” For perspective, remember that humanity at present releases yearly the equivalent of five Pinatubos—100 million tons of sulfur dioxide pollution—into the lower atmosphere, where its dimming effect keeps the Earth 2°-3°C cooler than if our air were clean. The estimated cost of injecting stratospheric sulfur would be $1 billion a year, which is shockingly little, considering its impact.
The way to test the technique, Caldeira and his colleagues propose, is with a localized effort in the Arctic. A relatively small amount of sulfur could be used; it could be injected into the lower stratosphere, so it would stay up only a year; few people live in the region; and the area needs cooling more than any other. The effects could be measured directly in ice behavior (and polar bear cubs), and increased ice would amplify the cooling effect by reflecting even more sunlight. It could be, editor Oliver Morton wrote in Nature, “as low-impact an option as the geoengineer’s toolbox offers.”
• Even more attractive, in terms of the ability to turn it off easily, is the idea of a fleet of oceangoing cloud machines. In 1990 atmospheric physicist John Latham came up with the idea of significantly brightening Earth’s albedo by simply adding more water droplets to the stratocumulus clouds that cover a third of the oceans. The droplets could come from atomized seawater. Engineer Stephen Salter designed a ship to do the job. It would be an unmanned pontoon ship, 150 feet long, controlled by satellite, utilizing towerlike Flettner sails to course back and forth across the wind. (The vessel is incredibly cool looking.) Turbines dragged beneath the surface would provide the power to spray seawater in 1-micron droplets at a rate of 500 gallons a minute. Latham and Salter estimate that 1,500 such ships, which would cost a total of about $3 billion to build, would brighten ocean clouds enough to offset a doubling of carbon dioxide in the atmosphere. Lovelock comments: “Because this approach has far fewer potential adverse side effects than the stratospheric aerosols, it should be tried on a sufficient scale to assess its worth.”
• So far, the most controversial geoengineering proposal has to do with feeding iron to the ocean’s carbon-fixing algae (also called phytoplankton, diatoms, and coccolithophores). Vast regions of the ocean surface are virtually devoid of phytoplankton, and no one could figure out why until biochemist John Martin suggested in 1990 that what makes the difference is the presence or absence of iron in dust blown from the land. A dozen experiments have proved his hypothesis correct: fertilizing the ocean with iron makes huge algal blooms. Now the question is, does the extra carbon fixed by the algae sink into the ocean depths, or does it circulate in food webs near the surface and return to the atmosphere as carbon dioxide? If the carbon sinks in the form of dead algae below a depth of 1,600 feet, then it will stay out of the atmosphere for at least a century; if it gets all the way to the bottom, it could be gone for thousands of years. During past ice ages, when dry land sent more iron-bearing dust into the oceans, 100 billion tons of carbon were sequestered in the sea.
In 2004 German oceanographer Victor Smetacek led an expedition of fifty scientists to conduct an iron-fertilization experiment in the ocean between South Africa and Antarctica. One month after the team dumped 3 tons of iron filings in the water, they detected large quantities of dead algae sinking many hundreds of feet below the extensive algal bloom, but they lacked equipment for detailed research at depth. In early 2009, Smetacek led another team (this time including many scientists from India’s National Institute of Oceanography) to the Southern Ocean with a plan to study the deep-ocean effects of fertilizing algal blooms with 20 tons of iron. Science reported:The new experiments will explore what happens to those blooms and whether they can be carbon sinks for atmospheric carbon dioxide. There’s a lot scientists don’t know, including why some blooms fall so rapidly, how much of them are devoured by microbes and other sea life on the way down, and which locations and plankton species do the best job of sequestering carbon.
ETC, the anti-genetic-engineering group in Canada, raised a howl of protest, quoting an environmental lawyer from South Africa’s Center for Biosafety: “We do not believe our country should be aiding and abetting these controversial geoengineers in breaking the global moratorium. We hav
e formally asked our Environment Ministry to compel the ship to return to port and offload its cargo of iron.” The moratorium referred to is a 2008 agreement (pushed by ETC and others) within the UN Convention on Biodiversity to cease ocean fertilization activities until there is “an adequate scientific basis on which to justify such activities.” In other words, in seeking to block the Smetacek research expedition (which was approved by the German and Indian governments), ETC and other environmental organizations were saying, “You must have scientific proof of the effectiveness of iron fertilization, and we will prevent you from getting it.”
The Bush administration blocked research on climate change for identical reasons—fear of findings that might go against an ideological position. Neither climate denialists nor ETC seem to consider that the research could go in their favor. They would rather believe than know. There is no excuse for environmentalists to block scientific research on environmental issues, ever.
• Jim Lovelock and Chris Rapley (former British Antarctic Survey director; now director of London’s Science Museum) have put forth an idea that is less controversial than iron fertilization but similar in purpose: An array of floating vertical pipes would provide nutrients to organisms near the ocean’s surface by drawing cold, nutrient-rich water up from the depths. The point is to break through the thermocline in stratified waters and deliver the nutrients to where the sunlight is, mimicking in miniature the upwellings that provide the ocean’s areas of greatest productivity and biodiversity. Lovelock and Rapley wrote in Nature: “Water pumped up pipes—say, 100 to 200 metres long, 10 metres in diameter and with a one-way flap valve at the lower end for pumping by wave movement—would fertilize algae in the surface waters and encourage them to bloom. This would pump down carbon dioxide and produce dimethyl sulphide, the precursor of nuclei that form sunlight-reflecting clouds.” With three-foot surface waves, the pipes would send four tons of cool water a second to the surface, using the ocean’s energy to do the work. Besides enriching biodiversity, the localized cooler water could protect coral reefs endangered by ocean heating, and weaken cyclones in places like the Gulf of Mexico by depriving them of the overheated seawater that turns a category 3 hurricane into a category 5 Katrina.
Geophysical Research Letters reported in 2008 that, over nine years, global warming has caused a 15 percent increase in barren regions of the ocean, due to the warmer water stratifying. Fewer clouds form over dead ocean regions for lack of the cloud-forming droplet nuclei usually provided by life on the ocean surface. If you take a world map of ocean chlorophyll and overlay it with a map of ocean cloud cover, you find watery deserts of enormous size—such as a region of the Pacific 1,000 miles wide stretching west from Latin America for 5,000 miles along the Tropic of Capricorn. In these ocean deserts, there is a dearth of life and clouds and an overabundance of sunlight heating the dark water and spreading the deadly stratification. It’s a double-whammy positive feedback—like the melting of polar ice and the drying of rainforests combined: Ever more sunlight is being absorbed and there is ever less plant life to fix carbon.
• Then there’s biochar. It looks like such a miracle material that I’m skeptical about its ability to scale up. Jim Lovelock is convinced that it can do so. He cites a paper by Cornell soil scientist Johannes Lehmann in Nature proposing that biochar is a more reliable method of sequestering carbon than just planting trees (they can burn), converting to no-till agriculture (the carbon-fixation gains level off in twenty years), or using geological storage sites for carbon dioxide (they can leak). “Once biochar is incorporated into soil,” Lehmann wrote, “it is difficult to imagine any incident or change in practice that would cause a sudden loss of stored carbon.”
In 2009 Lovelock told a New Scientist interviewer what it would take for biochar to scale up and what it would mean:There is one way we could save ourselves and that is through the massive burial of charcoal. It would mean farmers turning all their agricultural waste—which contains carbon that the plants have spent the summer sequestering—into non-biodegradable charcoal, and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the CO2 down quite fast. . . . Ninety-nine percent of the carbon that is fixed by plants is released back into the atmosphere within a year or so by consumers like bacteria, nematodes and worms. What we can do is cheat those consumers by getting farmers to burn their crop waste at very low oxygen levels to turn it into charcoal, which the farmer then ploughs into the field. A little CO2 is released but the bulk of it gets converted to carbon. You get a few percent of biofuel as a by-product of the combustion process, which the farmer can sell. This scheme would need no subsidy: the farmer would make a profit.
The world’s volume of timber and crop residue that might be pyrolyzed into biochar is truly massive. How sweet it will be if the terra preta technique invented thousands of years ago by Amazon Indians to solve their soil problems works today to help solve our atmosphere problems.
• A synthetic method for fixing carbon directly from the air is being pursued by an environmental engineer, Klaus Lackner at Columbia University. He proposes “artificial trees” that would capture carbon a thousand times more efficiently than living trees of the same size. Allen and Burt Wright at Global Research Technologies, based in Tucson, Arizona, have developed a working prototype. The device flows sodium carbonate down sheets of a proprietary plastic. The liquid reacts with carbon dioxide to form baking soda. Electrolysis separates the carbon dioxide from the baking soda and cycles the sodium carbonate for reuse. An extractor the size of a shipping container, Allen Wright claims, could capture a ton a day of CO2 at a cost of $30 a ton. The energy to run the extractor would have to come from a non-fossil-fuel source for the process to come out ahead on carbon, however.
What do you do with captured carbon dioxide? Because it is an industrial chemical (used in greenhouse horticulture, oil field enhancement, food processing and transport, water treatment, foam fabrication, dry ice, etc.), the company proposes collecting the CO2 at the site of use for commercial sale. There are also thoughts of “mineral sequestration”—forcing carbon dioxide, with heat or acid, to react with serpentine or peridotite rock to form extremely stable magnesium carbonate. “This is what nature eventually does anyway,” says Lackner. “Our goal is to take a process that takes 100,000 years and compress it into 30 minutes.”
• I first heard the idea of putting sunglasses directly on the Sun from Jim Lovelock in 1986; it scandalized and thrilled me at the time. These days it’s a serious proposal. The magical spot is the one Al Gore chose for the Earth-imaging and -sensing satellite DSCOVR—the Lagrange-1 site of neutral gravity between Earth and the Sun. (Gore hates the idea of solar shades at L-1. When I mentioned it to him, he said, “Oh right, Brand. Let’s just experiment with the whole planet!”)
There are several schemes afoot. The one that gets the most discussion so far comes from Roger Angel, a University of Arizona astronomer renowned for his work on telescope mirrors. His proposal, titled “Feasibility of Cooling the Earth with a Cloud of Small Spacecraft Near the Inner Lagrange Point (L1),” appeared in the Proceedings of the National Academy of Sciences in 2006. To dissipate 1.8 percent of the sunlight reaching Earth, which would be enough to offset a doubling of CO2 in the atmosphere, Angel would float 16 trillion two-foot disks in a cloud eight thousand miles wide and sixty thousand miles long, aligned between the Sun and Earth. The disks, each weighing a gram, could keep themselves on station “by modulating solar radiation pressure, with no need for expendable propellants.” (That means that the disks tack in the “wind” of sunlight like sailboats.)
To get 20 million tons of disks to L-1, Angel suggests electromagnetic rail guns for launch and ion-drive rockets for flight. New Scientist reported: “Angel has calculated that 20 rail guns, each 3 kilometers high, working round the clock and launching one bundle of discs every 5 minutes for 10 years, could put enough ‘pico-satellite’ discs into space to provide the requi
red 1.8 percent reduction in the sunlight reaching Earth. The cost would be in the region of a few trillion dollars.” (Angel ended his PNAS paper with these words: “The same massive level of technology innovation and financial investment needed for the sunshade could, if also applied to renewable energy, surely yield better and permanent solutions.”)
Heady stuff. One’s immediate response ricochets from “How dangerous and crazy!” to “How grand and thrilling!” to “How handy and cheap!” and back to “How dangerous and crazy!” But what happens when the considered response is “How necessary”? In late 2008, an English newspaper, the Independent, polled eighty climatologists about geoengineering. Over half of them said that the situation is growing so dire that we must have a geoengineering backup plan, while 35 percent said that such plans would distract people from the crucial task of reducing greenhouse gases (11 percent offered no opinion).
The first need is to run some large-scale experiments. The projects have to move from conceptual design to operational design—from scientists to engineers—with serious money attached. “There’s a lot more talk than work,” Ken Caldeira told Scientific American. “Most of the research has been at the hobby level.” Environmental scientists Thomas Homer-Dixon and David Keith wrote in the New York Times that geoengineering “is so taboo that governments have provided virtually no research money.” They urged that we should begin with “real-world tests of various technologies that poke the climate system just a little.” They concluded: “The important thing is to get scientists, environmentalists and global-warming skeptics alike out of the nonsensical all-or-nothing dichotomy that characterizes much current thinking about geoengineering—that we either do it full scale, or we don’t do it at all.”
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