Field Notes From a Catastrophe: Man, Nature, and Climate Change (15 page)

In the future, the growth of carbon emissions is likely to be determined by several forces. One is the rate of population growth; estimates of how many people will be living on the planet in 2050 range from a low of 7.4 billion to a high of 10.6 billion. Another is economic growth. A third factor is the rate at which new technologies are adopted. Particularly in the developing world, the demand for electricity is increasing rapidly; in China, for example, electricity consumption is expected to more than double by 2025. If developing nations satisfy this demand by adopting the latest, most energy-efficient technologies, then emissions will grow at one rate. (This possibility is sometimes referred to as “leapfrogging,” since it would require developing countries to “leapfrog” ahead of industrialized nations.) If they satisfy demand by deploying less efficient—but often cheaper—technologies, emissions will increase at a much faster rate.

“Business as usual” refers to a whole range of projections, all of which take as their primary assumption that emissions will continue to grow without regard to the climate. In 2005, global emissions amounted to roughly 7 billion metric tons of carbon. Under a midrange BAU projection, they will grow to 10.5 billion metric tons a year by 2029, and 14 billion tons a year by 2054. Under this same projection, CO
₂
levels in the atmosphere will reach 500 parts per million by the middle of the century, and if things continue on the same trajectory, CO
₂
will reach 750 parts per million, or roughly three times preindustrial levels, by the year 2100.

Looking at these figures, Socolow reached a couple of conclusions right away. The first was that to avoid exceeding CO
₂
concentrations of 500 parts per million, immediate action would be needed. The second was that to meet this target, emissions growth would have to be held essentially to zero. Stabilizing CO
₂
emissions would be such an enormous undertaking that Socolow decided to break the problem down into more manageable blocks, which he called “stabilization wedges.” For simplicity’s sake, he defined a stabilization wedge as a step that would be sufficient to prevent a billion metric tons of carbon per year from being emitted by 2054. Since annual carbon emissions now amount to 7 billion metric tons, and in fifty years are expected to reach 14 billion metric tons, seven wedges would be needed to hold emissions constant at today’s level. With the help of a Princeton colleague, Stephen Pacala, Socolow eventually came up with fifteen different wedges—theoretically, at least, eight more than would be necessary. In August 2004, Socolow and Pacala published their findings in a paper in
Science
that received a great deal of attention. The paper was at once upbeat—“Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century,” it declared—and deeply sobering. “There is no easy wedge” is how Socolow put it to me.

Consider wedge No. 11. This is the photovoltaic, or solar power, wedge—probably the most appealing of all the alternatives, at least in the abstract. Photovoltaic cells, which have been around for more than fifty years, are already in use in all sorts of small-scale applications and in some larger ones where the cost of connecting to the electrical grid is prohibitively high. The technology, once installed, is completely emissions-free, producing no waste products, not even water. For the purpose of their calculations, Socolow and Pacala assumed that a one-thousand-megawatt coal-fired power plant would produce about 1.5 million tons of carbon a year. (Today’s coal plants actually produce some 2 million tons of carbon a year, but in the future, plants are expected to become more efficient.) To reduce emissions by a billion metric tons a year, enough solar cells would therefore have to be installed to obviate the need for nearly seven hundred thousand-megawatt coal plants. Since sunshine is not constant—it is interrupted by nightfall and by clouds—some two million megawatts of capacity would be needed. This, it turns out, would require PV arrays covering a surface area of five million acres—approximately the size of Connecticut.

One “wedge” would prevent a billion tons of carbon a year from being emitted by 2054. Credit: S. Pacala and R. Socolow
, Science,
vol. 305 (2004).

Wedge No. 10 is wind electricity. Again, the technology has the advantage of being both safe and emissions-free. A large turbine can generate two megawatts of power, but since the wind, like sunlight, is intermittent, to get a wedge out of wind power would require at least a million two-megawatt turbines. Wind turbines are generally installed either offshore, or on hilltops or windy plains. When they are installed on land, the area around them can be used for other purposes, such as farming, but a million turbines would effectively “occupy” thirty million acres, an area roughly the size of New York state.

Other wedges present different challenges, some technical, some social. Nuclear power produces no carbon dioxide, but it generates radioactive waste, with all the attendant difficulties of storage, disposal, and international policing. More than forty years after the first commercial reactors went online, the United States has been unable to solve its nuclear waste problems, and several power plant operators have sued the federal government over its failure to construct a long-term waste storage site. Worldwide, there are 441 nuclear power plants currently in operation; one wedge could be achieved by doubling their capacity. There is also one heating and lighting wedge, which would result from cutting energy use in residential and commercial buildings by a quarter, and two automobile wedges. The first auto wedge would require that every car in the world be driven half as much as it is today, the second that it be twice as efficient. (Since the late 1980s, the fuel efficiency of passenger vehicles in the United States has actually declined, by more than 5 percent.)

Another possible option is a technology known as “carbon capture and storage,” or CCS. As the name suggests, with CCS carbon dioxide is “captured” at the source—presumably a large emitter—and then injected at very high pressure into geological formations, such as depleted oil fields, underground. (At such pressure, CO
₂
becomes “supercritical,” a phase in which it is not quite a liquid and not quite a gas.) One wedge in Socolow’s plan comes from “capturing” CO
₂
from power plants, another from capturing it from synthetic-fuel manufacturers. The basic techniques of CCS are currently employed to increase production from oil and natural gas wells. However, at this point, there are no synthetic-fuel or power plants using the process. Nor does anyone know for certain how long CO
₂
injected underground will remain there. The world’s longest-running CCS effort, maintained by the Norwegian oil company Statoil at a natural gas field in the North Sea, has been operational only for about a decade. A wedge of CCS would require thirty-five hundred projects on the scale of Statoil’s.

In a world like today’s, where there is, for the most part, no direct cost to emitting CO
₂
, none of Socolow’s wedges are apt to be implemented; this is, of course, why they represent a departure from “business as usual.” To alter the economics against carbon requires government intervention. Countries could set a strict limit on CO
₂
, and then let emitters buy and sell carbon “credits.” (In the United States, this same basic strategy has been used successfully with sulfur dioxide in order to curb acid rain.) Another alternative is to levy a tax on carbon. Both of these options have been extensively studied by economists; using their work, Socolow estimates that the cost of emitting carbon would have to rise to around a hundred dollars a ton to provide a sufficient incentive to adopt many of the options he has proposed. Assuming that the cost were passed on to consumers, a hundred dollars a ton would raise the price of a kilowatt-hour of coal-generated electricity by about two cents, which would add roughly fifteen dollars a month to the average American family’s electricity bill.

All of Socolow’s calculations are based on the notion—clearly hypothetical—that steps to stabilize emissions will be taken immediately, or at least within the next few years. This assumption is key not only because we are constantly pumping more CO
₂
into the atmosphere but also because we are constantly building infrastructure that, in effect, guarantees that that much additional CO
₂
will be released in the future. In the United States, the average new car gets about twenty miles to the gallon; if it is driven a hundred thousand miles, it will produce more than eleven metric tons of carbon. A thousand-megawatt coal plant built today, meanwhile, is likely to last fifty years and to emit some hundred million tons of carbon during its life. The overriding message of Socolow’s wedges is that the longer we wait—and the more infrastructure we build without regard to its impact on emissions—the more daunting the task of keeping CO
₂
levels below 500 parts per million will become.

Indeed, even if we were to hold emissions steady for the next half century, Socolow’s graphs show that much steeper cuts would be needed in the following half century to keep CO
₂
concentrations from exceeding that level. Carbon dioxide is a persistent gas; it lasts for about a century. Thus, while it is possible to increase CO
₂
concentrations relatively quickly, the opposite is not the case. (The effect might be compared to driving a car equipped with an accelerator but no brakes.) After a while, I asked Socolow whether he thought that stabilizing emissions was apolitically practical goal. He frowned.

“I’m always being asked, ‘What can you say about the practicability of various targets?’ ” he told me. “I really think that’s the wrong question. These things can all be done.

“What kind of issue is like this that we faced in the past?” he continued. “I think it’s the kind of issue where something looked extremely difficult, and not worth it, and then people changed their minds. Take child labor. We decided we would not have child labor and goods would become more expensive. It’s a changed preference system. Slavery also had some of those characteristics a hundred and fifty years ago. Some people thought it was wrong, and they made their arguments, and they didn’t carry the day. And then something happened and all of a sudden it was wrong and we didn’t do it anymore. And there were social costs to that. I suppose cotton was more expensive. We said, ‘That’s the trade-off; we don’t want to do this anymore.’ So we may look at this and say, ‘We are tampering with the earth.’ The earth is a twitchy system. It’s clear from the record that it does things that we don’t fully understand. And we’re not going to understand them in the time period we have to make these decisions. We just know they’re there. We may say, ‘We just don’t want to do this to ourselves.’ If it’s a problem like that, then asking whether it’s practical or not is really not going to help very much. Whether it’s practical depends on how much we give a damn.”

Marty Hoffert is a professor of physics at New York University. He is big and bearish, with a wide face and silvery hair. Hoffert got his undergraduate degree in aeronautical engineering, and one of his first jobs, in the mid-1960s, was helping to develop the United States’s antiballistic-missile system. During the week, Hoffert worked at a lab in New York, and sometimes he would go down to Washington to meet with Pentagon officials. Over the weekend, on occasion, he would travel back to Washington to protest Pentagon policy. Eventually, he decided that he wanted to work on something, in his words, “more productive.” In this way, he became involved in climate research. He calls himself a “technological optimist,”and a lot of his ideas about electric power have a wouldn’t-it-be-cool, Buck Rogers sound to them. On other topics, though, Hoffert is a killjoy.

“We have to face the quantitative nature of the challenge,” he told me one day over lunch at the NYU faculty club. “Right now, we’re going to just burn everything up; we’re going to heat the atmosphere to the temperature it was in the Cretaceous, when there were crocodiles at the poles. And then everything will collapse.”

Hoffert is primarily interested in finding new, carbon-free ways to generate energy. Currently, the technology that he is pushing is space-based solar power, or SSP. In theory, at least, SSP involves launching into space satellites equipped with massive photovoltaic arrays. Once a satellite is in orbit, the array would unfold or, according to some plans, inflate. SSP has two important advantages over conventional, land-based solar power. In the first place, there is more sunlight in space—roughly eight times as much, per unit of area—and, in the second, this sunlight is constant: satellites are not affected by clouds or by nightfall. The obstacles, meanwhile, are several. No full-scale test of SSP has ever been conducted. (In the 1970s, NASA studied the idea of sending a photovoltaic array the size of Manhattan into space, but the project never, as it were, got off the ground.) Then, there is the expense of launching satellites. Finally, once the arrays are up, there is the difficulty of getting the energy down. Hoffert imagines solving this last problem by using microwave beams of the sort used by cell phone towers, only much more tightly focused. He believes, as he put it to me, that SSP has a great deal of “long-term promise”; however, he is quick to point out that he is open to other ideas, like putting solar collectors on the moon, or using superconducting wires to transmit electricity with minimal energy loss, or generating wind power using turbines suspended in the jet stream. The important thing, he says, is not
which
new technology will work but simply that
some
new technology be found: “There’s an argument that our civilization can continue to exist with the present number of people and the present kind of high technology through conservation. I see that argument as similar to a man being locked in a sealed room with a limited amount of oxygen. And if he breathes more slowly, he’ll be able to live longer, but what he really needs is to get out of the room. And I want to get out of the room.” A few years ago, Hoffert published an influential paper in
Science
in which he argued that holding CO
₂
levels below 500 parts per million would require a “Herculean” effort and probably could be accomplished only through “revolutionary” changes in energy production.