None of this is what makes Christopher Knittel use words like catastrophe. What Knittel is thinking of is, so to speak, the little black specks of Yulin, China. Five years ago, I traveled with a friend to Yulin, in the northwestern province of Shaanxi, not far from Mongolia. We visited the Great Wall, which passes just north of town. In that area, the wall itself had mostly crumbled to nothing, except for the watchtowers, which stuck up every half mile or so. People in one tower were supposed to be able to signal to the next, passing on messages like ships at sea.
When I climbed up one eroded tower, I was surprised to find that I couldn't see its neighbor. There were little black specks all over my glasses. I cleaned the lenses, but was still unable to make out the next tower. The black specks were not just on my glasses.
Walking around town, my friend and I had noticed that almost every home had a pile of coal outside, soft dark chunks that people shoveled into stoves for cooking and heating. Thousands upon thousands of coal fires were loading the air with tiny dots of soot. Scientists have taken to calling these dots "black carbon," and have steadily ratcheted up their assessments of its harm. In March, for instance, a research team led by a Mumbai environmental group estimated that black carbon and other particulate matter from India's coal-fired power plants cause about 100,000 deaths a year.
Environmentalists worry even more about black carbon's role in climate change. Black carbon in the air absorbs heat and darkens clouds. In some places, it alters rain patterns. Falling on snow, it accelerates melting. A 31-scientist team from nine nations released a comprehensive, four-year assessment in January arguing that planetary black-carbon output is the second-biggest driver of anthropogenic (human-caused) climate change; the little black specks I found on my glasses and clothes have roughly two-thirds the impact of carbon dioxide.
Natural gas produces next to no soot and half the carbon dioxide coal does. In coal-heavy places like China, India, the former Soviet Union, and eastern Europe, heating homes and offices with natural gas instead of coal would be a huge step. An MIT study chaired by Ernest Moniz, whom President Obama nominated for energy secretary in March, called natural gas "a cost-effective bridge" to a "low-carbon future."
The Chinese government is aware of this, which is one reason it is pursuing both shale gas and methane hydrate. But environmentalists are less enthusiastic than one might imagine about the prospect of weaning ourselves from coal with gas. The reason is that methane itself—unburned natural gas—has a much greater capacity to trap solar heat than carbon dioxide does. (Because methane does not remain in the air as long as carbon dioxide, the precise comparison depends on the chosen time frame; researchers typically say that methane is about 20 or 30 times more potent.) Activists fear that the negative effects of obtaining natural gas could swamp the positive effects of burning it. They are entirely correct, although perhaps not in the way they suppose.
Almost every friend and neighbor I have spoken with about methane hydrate asked whether tapping these undersea deposits could release vast amounts of methane all at once, disastrously altering the planet's environment. According to Carolyn Ruppel of the Geological Survey, these fears are understandable—but misplaced. If things go awry in a hydrate operation, some of the methane will escape into exactly the cold temperatures and high pressures that trapped it to begin with. Some will be consumed by bacteria, producing carbon dioxide, which dissolves in water; this raises the ocean's acidity, but not enough to have much effect. Any remaining methane will rise out of the sediment and, like the carbon dioxide, dissolve harmlessly in the ocean. (None of this should be confused with a different source of methane: the decayed vegetation in permafrost, which will release methane if the permafrost thaws.)
The real concern, Ruppel and other researchers told me, is less an explosive methane release from under the Earth's surface—the environmental disaster that might have caused havoc eons ago—than a slow discharge at ground level, from the machinery that will pull methane hydrate out of the seafloor. The problem already exists with fracking. "The rule of thumb is that if a well leaks more than about 3 percent" of its methane production into the air, "natural gas actually becomes dirtier than coal, from a climate-change perspective," says Ramez Naam, the author of The Infinite Resource, a just-published book about the race between environmental degradation and technological innovation. "The amazing thing, though, is that we don't have any data—nobody is required to monitor methane at the well. So there's just a few studies, which vary tremendously." Worse still, the aging natural-gas infrastructure is riddled with holes and seeps; early this year, a survey of gas mains along Boston's 785 miles of road, the first-ever such examination, found 3,356 leaks. Last August, the Environmental Protection Agency amended the Clean Air Act to require well operators to recapture some methane; because nobody knows how much natural gas is gushing into the air, the new rules' impact is uncertain.
Still, fixing leaks is a task that developed nations can accomplish. "In the United States," Lynch says, "it is possible to hire inspectors and send them out in white vans to measure methane emissions. They can tell companies to spray more silicone in the wellheads. Maybe the companies will kick and scream about the bureaucracy and cost, but this is something that can be done."
What we can't do, or at least not readily, is overcome the laws of economics.
What we can't do, or at least not readily, is overcome the laws of economics.
In these visions of the future, natural gas plays two roles. To politicians and economists, it is a vehicle for reasserting American might—cheap energy that will liberate the United States from foreign petroleum. To environmentalists, natural gas is a bridge fuel, a substitute for coal and oil that will serve until—but only until—the world can move to zero-carbon energy sources: sunlight, wind, tides, waves, and geothermal heat.
In the short run, these visions are compatible. Although the cost of renewable energy is falling rapidly, it is not yet equivalent to the cost of energy from fossil fuels. As an example, typical solar cells today have an EROEI of about 10—better than tar sands but worse than most oil and gas. (All such estimates are rough in the extreme, because the output of renewables, unlike that of petroleum, depends on where they are located. One recent estimate put the EROEI of Spain's extensive solar-power network at less than 3.) Many advocates for solar power believe that its EROEI will match that of fossil fuels within a decade. Even if they are correct, though, sunlight is too fickle and inconstant for utilities. Modern electrical grids are in some ways like busy airports, with sweaty controllers staring at monitors, feverishly adjusting power outputs from big plants to the capricious swirls of human demand for air-conditioning, baseboard heating, and microwave popcorn. As more and more energy comes from sun, wind, tides, and other variable sources, the problem of balancing fluctuating supply and fluctuating demand will worsen. When renewables supply 20 to 30 percent of all electricity, many utility-energy engineers predict, the system will no longer be able to balance supply and demand. Brownouts will ripple across the landscape; control centers will call up big companies and beg them to turn off the lights; managers of ultrasensitive modern control centers will watch in horror as voltage drops lead to factory shutdowns. (Germany, a leader in renewable-energy use, is already facing this situation.) To ask utilities to take in large amounts of solar power—electricity generated by hundreds or thousands of small installations, many on neighborhood roofs and lawns, whose output is affected by clouds—is like asking a shipping firm to replace its huge, professionally staffed container ships with squadrons of canoes paddled by random adolescents. Other renewables can be more reliable than power from the sun, to be sure, but all are costlier than petroleum and hard to fit into today's grid. Natural gas, from this point of view, seems like the perfect stopgap.
The clash occurs when renewables are ready for prime time—and natural gas is still hanging around like an old and dirty but reliable car, still cheap to produce and use, after shale fracking is replaced globally by undersea mining of methane hydrate. Revamping the electrical grid from conventionals like coal and oil to accommodate unconventionals like natural gas and solar power will be enormously difficult, economically and technically. Facilities must be constructed to store extra energy for dark, windless days; transmission lines will need to be built to move power from warm places like New Mexico to cold places like New England; grids will have to be reworked to allow small energy producers to share directly with neighbors rather than being forced to pump everything into large power centers. All of this will be a burden on businesses and consumers alike. But it must be done to avert climate change, because electricity generation is responsible for about a third of America's greenhouse-gas emissions. Roughly similar figures hold true in other developed nations.
Most oil specialists agree that humankind is naturally progressing toward a no-carbon energy future. Our species has already moved from wood to coal to oil to gas, each fuel burning cleaner than its predecessor. Wind, solar, and other renewables are obvious next steps. The problem, scientists say, is that climate change is happening too quickly. Instead of evolving over decades, as happened with the building of the electrical grid, the changeover to renewables has to occur now, faster than any change before.
True, there are ways of buying time. Scientists have experimented, for instance, with injecting carbon dioxide into methane hydrate; for complex chemical reasons, the crystals "prefer" the carbon dioxide, taking it in and expelling natural gas. If undersea methane hydrate could be mined in this fashion, the sequestered carbon dioxide, forever imprisoned in ice beneath the waves, would offset some emissions. This new kind of carbon sequestration could ameliorate some of the long-term environmental damage that widespread global use of cheap natural gas from methane hydrate will do. But even if such techniques work in the way researchers hope, the infrastructure transformation ahead is daunting in scale and scope. It's like setting up a second Industrial Revolution, only all over the world and in one-third the time.
For years, environmentalists have hoped that the imminent exhaustion of oil will, in effect, force us to undergo this virtuous transition. That hope seems likely to be denied.
For years, environmentalists have hoped that the imminent exhaustion of oil will, in effect, force us to undergo this virtuous transition; given a choice between no power and solar power, even the most shortsighted person would choose the latter. That hope seems likely to be denied. Cheap, abundant petroleum threw sand in the gears of solar power in the 1980s and stands ready to do it again. Plentiful natural gas, a geopolitical and economic boon, is a climatological shackle. To Vaclav Smil, the University of Manitoba environmental scientist, the notion that we can move so fast is naive, even preposterous. "Energy transitions are always slow," he told me by e-mail. Modern energy infrastructures, assembled over decades, cannot be revamped overnight. Worse still, in his view, there is little public appetite for beginning the process, or even appreciating the magnitude of what lies ahead. "The world has been running into fossil fuels, not away from them."
Smil is correct—the sort of rapid energy transition we need has never occurred before. At the same time, one should note that no physical law says these transitions must be slow. Societies have changed rapidly, even when it cost a lot of money. Nobody can predict the future, but it is dumbfounding to hear left and right alike bemoaning the "reality" that society cannot change, particularly at a time when both sides are bemoaning the consequences of convulsive social change. Natural gas, both from fracking and in methane hydrate, gives us a way to cut back on carbon emissions while we work toward a more complete solution. It could be a useful crutch. But only if we have the wit to know that we will soon have to lay it down.