END OF OIL?.

Today our planet is thoroughly wedded to fossil fuels in the form of oil, natural gas, and coal. Altogether, the world consumes about 14 trillion watts of power, of which 33 percent comes from oil, 25 percent from coal, 20 percent from gas, 7 percent from nuclear, 15 percent from bioma.s.s and hydroelectric, and a paltry .5 percent from solar and renewables.

Without fossil fuels, the world economy would come to a grinding halt.

One man who clearly saw the end of the age of oil was M. King Hubbert, a Sh.e.l.l Oil petroleum engineer. In 1956, Hubbert presented a far-reaching talk to the American Petroleum Inst.i.tute, making a disturbing prediction that was universally derided by his colleagues at the time. He predicted that U.S. oil reserves were being depleted so rapidly that soon 50 percent of the oil would be taken out of the ground, triggering an irreversible era of decline that would set in between 1965 and 1971. He saw that the total amount of oil in the United States could be plotted as a bell-shaped curve, and that we were then near the top of that curve. From then on, things could only go downhill, he predicted. This meant that oil would become increasingly difficult to extract, hence the unthinkable would happen: the United States would begin importing oil.

His prediction seemed rash, even outlandish and irresponsible, since the United States was still pumping an enormous amount of oil from Texas and elsewhere in this country. But oil engineers are not laughing anymore. Hubbert"s prediction was right on the b.u.t.ton. By 1970, U.S. oil production peaked at 10.2 million barrels a day and then fell. It has never recovered. Today, the United States imports 59 percent of its oil. In fact, if you compare a graph of Hubbert"s estimates made decades ago with a graph of actual U.S. oil production through 2005, the two curves are almost identical.

Now the fundamental question facing oil engineers is: Are we at the top of Hubbert"s peak in world oil reserves? Back in 1956, Hubbert also predicted that global oil production would peak in about fifty years. He could be right again. When our children look back at this era, will they view fossil fuels the same way we view whale oil today, as an unfortunate relic of the distant past?

I have lectured many times in Saudi Arabia and throughout the Middle East, speaking about science, energy, and the future. On one hand, Saudi Arabia has 267 billion barrels of oil, so this country seems to be floating on a huge underground lake of crude oil. Traveling throughout Saudi Arabia and the Persian Gulf states, I could see an exorbitant waste of energy, with huge fountains gushing in the middle of the desert, creating mammoth artificial ponds and lakes. In Dubai, there is even an indoor ski slope with thousands of tons of artificial snow, in utter defiance of the sweltering heat outside.

But now the oil ministers are worried. Behind all the rhetoric of "proven oil reserves," which are supposed to rea.s.sure us that we will have plenty of oil for decades to come, there is the realization that many of these authoritative oil figures are a deceptive form of make-believe. "Proven oil reserves" sounds soothingly authoritative and definitive, until you realize that the reserves are often the creation of a local oil minister"s wishful thinking and political pressure.

Speaking to the experts in energy, I could see that a rough consensus is emerging: we are either at the top of Hubbert"s peak for world oil production, or are perhaps a decade away from that fateful point. This means that in the near future, we may be entering a period of irreversible decline.

Of course, we will never totally run out of oil. New pockets are being found all the time. But the cost of extracting and refining these will gradually skyrocket. For example, Canada has huge tar sands deposits, enough to supply the world"s oil for decades to come, but it is not cost-effective to extract and refine it. The United States probably has enough coal reserves to last 300 years, but there are legal restrictions, and the cost of extracting all the particulate and gaseous pollutants is onerous.

Furthermore, oil continues to be found in politically volatile regions of the world, contributing to foreign instability. Oil prices, when graphed over the decades, are like a roller-coaster ride, peaking at an astonishing $140 per barrel in 2008 (and more than $4 per gallon at the gas pump) and then plunging due to the great recession. Although there are wild swings, due to political unrest, speculation, rumors, etc., one thing is clear: the average price of oil will continue to rise over the long term.

This will have profound implications for the world economy. The rapid rise of modern civilization in the twentieth century has been fueled by two things: cheap oil and Moore"s law. With energy prices rising, this puts pressure on the world"s food supply as well as on the control of pollution. As novelist Jerry Pournelle has said, "Food and pollution are not primary problems: they are energy problems. Given sufficient energy we can produce as much food as we like, if need be, by high-intensity means such as hydroponics and greenhouses. Pollution is similar: given enough energy, pollutants can be transformed into manageable products; if need be, disa.s.sembled into their const.i.tuent products."

We also face another issue: the rise of a middle cla.s.s in China and India, one of the great demographic changes of the postwar era, which has created enormous pressure on oil and commodity prices. Seeing McDonald"s hamburgers and two-car garages in Hollywood movies, they also want to live the American dream of wasteful energy consumption.

SOLAR/HYDROGEN ECONOMY.

In this regard, history seems to be repeating itself. Back in the 1900s, Henry Ford and Thomas Edison, two longtime friends, made a bet as to which form of energy could fuel the future. Henry Ford bet on oil replacing coal, with the internal combustion engine replacing steam engines. Thomas Edison bet on the electric car. It was a fateful bet, whose outcome would have a profound effect on world history. For a while, it appeared that Edison would win the bet, since whale oil was extremely hard to get. But the rapid discovery of cheap oil deposits in the Middle East and elsewhere soon had Ford emerging victorious. The world has never been the same since. Batteries could not keep up with the phenomenal success of gasoline. (Even today, pound for pound, gasoline contains roughly forty times more energy than a battery.) But now the tide is slowly turning. Perhaps Edison will win yet, a century after the bet was made.

The question being asked in the halls of government and industry is: What will replace oil? There is no clear answer. In the near term, there is no immediate replacement for fossil fuels, and there most likely will be an energy mix, with no one form of energy dominating the others.

But the most promising successor is solar/hydrogen power (based on renewable technologies like solar power, wind power, hydroelectric power, and hydrogen).

At the present time, the cost of electricity produced from solar cells is several times the price of electricity produced from coal. But the cost of solar/hydrogen keeps plunging due to steady technological advances, while the cost of fossil fuels continues its slow rise. It is estimated that within ten to fifteen years or so, the two curves will cross. Then market forces will do the rest.

WIND POWER.

In the short term, renewables like wind power are a big winner. Worldwide, generating capacity from wind grew from 17 billion watts in 2000 to 121 billion watts in 2008. Wind power, once considered a minor player, is becoming increasingly prominent. Recent advances in wind turbine technology have increased the efficiency and productivity of wind farms, which are one of the fastest-growing sectors of the energy market.

The wind farms of today are a far cry from the old windmills that used to power farms and mills in the late 1800s. Nonpolluting and safe, a single wind power generator can produce 5 megawatts of power, enough for a small village. A wind turbine has huge, sleek blades, about 100 feet long, that turn with almost no friction. Wind turbines create electricity in the same way as hydroelectric dams and bicycle generators. The rotating motion spins a magnet inside a coil. The spinning magnetic field pushes electrons inside the coil, creating a net current of electricity. A large wind farm, consisting of 100 windmills, can produce 500 megawatts, comparable to the 1,000 megawatts produced by a single coal-burning or nuclear power plant.

Over the past few decades, Europe has been the world"s leader in wind technology. But recently, the United States overtook Europe in generating electricity from wind. In 2009, the United States produced just 28 billion watts from wind power. But Texas alone produces 8 billion watts from wind power and has 1 billion watts in construction, and even more in development. If all goes as planned, Texas will generate 50 billion watts of electrical power from wind, more than enough to satisfy the state"s 24 million people.

China will soon surpa.s.s the United States in wind power. Its Wind Base program will create six wind farms with a generating capacity of 127 billion watts.

Although wind power looks increasingly attractive and will undoubtedly grow in the future, it cannot supply the bulk of energy for the world. At best, it will be an integral part of a larger energy mix. Wind power faces several problems. Wind power is generated only intermittently, when the wind blows, and only in a few key regions of the world. Also, because of losses in the transmission of electricity, wind farms have to be close to cities, which further limits their usefulness.

HERE COMES THE SUN.

Ultimately, all energy comes from the sun. Even oil and coal are, in some sense, concentrated sunlight, representing the energy that fell on plants and animals millions of years ago. As a consequence, the amount of concentrated sunlight energy stored within a gallon of gasoline is much larger than the energy we can store in a battery. That was the fundamental problem facing Edison in the last century, and it is the same problem today.

Solar cells operate by converting sunlight directly into electricity. (This process was explained by Einstein in 1905. When a particle of light, or a photon, hits a metal, it kicks out an electron, thereby creating a current.) Solar cells, however, are not efficient. Even after decades of hard work by engineers and scientists, solar cell efficiency hovers around 15 percent. So research has gone in two directions. The first is to increase the efficiency of solar cells, which is a very difficult technical problem. The other is to reduce the cost of the manufacture, installation, and construction of solar parks.

For example, one might be able to supply the electrical needs of the United States by covering the entire state of Arizona with solar cells, which is impractical. However, land rights to large chunks of Saharan real estate have suddenly become a hot topic, and investors are already creating ma.s.sive solar parks in this desert to meet the needs of European consumers.

Or in cities, one might be able to reduce the cost of solar power by covering homes and buildings with solar cells. This has several advantages, including eliminating the losses that occur during the transmission of power from a central power plant. The problem is one of reducing costs. A quick calculation shows that you would have to squeeze every possible dollar to make these ventures profitable.

Although solar power still has not lived up to its promise, the recent instability in oil prices has spurred efforts to finally bring solar power to the marketplace. The tide could be turning. Records are being broken every few months. Solar voltaic production is growing by 45 percent per year, almost doubling every two years. Worldwide, photovoltaic installation is now 15 billion watts, growing by 5.6 billion watts in 2008 alone.

In 2008, Florida Power & Light announced the largest solar plant project in the United States. The contract was given by SunPower, which plans to generate 25 megawatts of power. (The current record holder in the United States is the Nellis Air Force Base in Nevada, with a solar plant that generates 15 megawatts of solar power.) In 2009, BrightSource Energy, based in Oakland, California, announced plans to beat that record by building fourteen solar plants, generating 2.6 billion watts, across California, Nevada, and Arizona.

One of BrightSource"s projects is the Ivanpah solar plant, consisting of three solar thermal plants to be based in Southern California, which will produce 440 megawatts of power. In a joint project with Pacific Gas and Electric, BrightSource plans to build a 1.3 billion watt plant in the Mojave Desert.

In 2009, First Solar, the world"s largest manufacturer of solar cells, announced that it will create the world"s largest solar plant just north of the Great Wall of China. The ten-year contract, whose details are still being hammered out, envisions a huge solar complex containing 27 million thin-film solar panels that will generate 2 billion watts of power, or the equivalent of two coal-fired plants, producing enough energy to supply 3 million homes. The plant, which will cover twenty-five square miles, will be built in Inner Mongolia and is actually part of a much larger energy park. Chinese officials state that solar power is just one component of this facility, which will eventually supply 12 billion watts of power from wind, solar, bioma.s.s, and hydroelectric.

It remains to be seen whether these ambitious projects will finally negotiate the gauntlet of environmental inspections and cost overruns, but the point is that solar economics are gradually undergoing a sea change, with large solar companies seriously viewing solar power as being compet.i.tive with fossil fuel plants.

ELECTRIC CAR.

Since about half the world"s oil is used in cars, trucks, trains, and planes, there is enormous interest in reforming that sector of the economy. There is now a race to see who will dominate the automotive future, as nations make the historic transition from fossil fuels to electricity. There are several stages in this transition. The first is the hybrid car, already on the market, which uses a combination of electricity from a battery and gasoline. This design uses a small internal combustion engine to solve the long-standing problems with batteries: it is difficult to create a battery that can operate for long distances as well as provide instantaneous acceleration.

But the hybrid is the first step. The plug-in hybrid car, for example, has a battery powerful enough to run the car on electrical power for the first fifty miles or so before the car has to switch to its gasoline engine. Since most people do their commuting and shopping within fifty miles, it means that these cars are powered only by electricity during that time.

One major entry into the plug-in hybrid race is the Chevy Volt, made by General Motors. It has a range of 40 miles (using only a lithium-ion battery) and a range of 300 miles using the small gasoline engine.

And then there is the Tesla Roadster, which has no gasoline engine at all. It is made by Tesla Motors, a Silicon Valley company that is the only one in North America selling fully electric cars in series production. The Roadster is a sleek sports car that can go head-to-head with any gasoline-fired car, putting to rest the idea that electric lithium-ion batteries cannot compete against gasoline engines.

I had a chance to drive a two-seat Tesla, owned by John Hendricks, founder of Discovery Communications, the parent company of the Discovery Channel. As I sat in the driver"s seat, Mr. Hendricks urged me to hit the accelerator with all my might to test his car. Taking his advice, I floored the accelerator. Immediately, I could feel the sudden surge in power. My body sank into the seat as I hit 60 miles per hour in just 3.9 seconds. It is one thing to hear an engineer boast about the performance of fully electric cars; it is another thing to hit the accelerator and feel it for yourself.

The successful marketing of the Tesla has forced mainstream automakers to play catch-up, after decades of putting down the electric car. Robert Lutz, when he was vice chairman of General Motors, said, "All the geniuses here at General Motors kept saying lithium-ion technology is ten years away, and Toyota agreed with us-and boom, along comes Tesla. So I said, "How come some tiny little California startup, run by guys who know nothing about the car business, can do this and we can"t?""

Nissan Motors is leading the charge to introduce the fully electric car to the average consumer. It is called the Leaf, has a range of 100 miles, a top speed of up to ninety miles per hour, and is fully electric.

After the fully electric car, another car that will eventually hit the showrooms is the fuel cell car, sometimes called the car of the future. In June 2008, Honda Motor Company announced the debut of the world"s first commercially available fuel cell car, the FCX Clarity. It has a range of 240 miles, has a top speed of 100 miles per hour, and has all the amenities of a standard four-door sedan. Using only hydrogen as fuel, it needs no gasoline and no electric charge. However, because the infrastructure for hydrogen does not yet exist, it is available for leasing in the United States only in Southern California. Honda is also advertising a sports car version of its fuel cell car, called the FC Sport.

Then in 2009, GM, emerging from bankruptcy after its old management was summarily fired, announced that its fuel cell car, the Chevy Equinox, had pa.s.sed the million-mile mark in terms of testing. For the past twenty-five months 5,000 people have been testing 100 of these fuel cell cars. Detroit, chronically lagging behind j.a.pan in introducing small car technology and hybrids, is trying to get a foothold in the future.

On the surface, the fuel cell car is the perfect car. It runs by combining hydrogen and oxygen, which then turns into electrical energy, leaving only water as the waste product. It creates not an ounce of smog. It"s almost eerie looking at the tailpipe of a fuel cell car. Instead of choking on the toxic fumes billowing from the back, all you see are colorless, odorless droplets of water.

"You put your hand over the exhaust pipe and the only thing coming out is water. That was such a cool feeling," observed Mike Schwabl, who test-drove the Equinox for ten days.

Fuel cell technology is nothing new. The basic principle was demonstrated as far back as 1839. NASA has used fuel cells to power its instruments in s.p.a.ce for decades. What is new is the determination of car manufacturers to increase production and bring down costs.

Another problem facing the fuel cell car is the same problem that dogged Henry Ford when he marketed the Model T. Critics claimed that gasoline was dangerous, that people would die in horrible car accidents, being burned alive in a crash. Also, you would have to have a gasoline pump on nearly every block. On all these points, the critics were right. People do die by the thousands every year in gruesome car accidents, and we see gasoline stations everywhere. But the convenience and utility of the car are so great that people ignore these facts.

Now the same objections are being raised against fuel cell cars. Hydrogen fuel is volatile and explosive, and hydrogen pumps would have to be built every few blocks. Most likely, the critics are right again. But once the hydrogen infrastructure is in place, people will find pollution-free fuel cell cars to be so convenient that they will overlook these facts. Today, there are only seventy refueling stations for fuel cell cars in the entire United States. Since fuel cell cars have a range of about 170 miles per fill-up, it means you have to watch the fuel meter carefully as you drive. But this will change gradually, especially if the price of the fuel car begins to drop with ma.s.s production and advances in technology.

But the main problem with the electric car is that the electric battery does not create energy from nothing. You have to charge the battery in the first place, and that electricity usually comes from a coal-burning plant. So even though the electric car is pollution free, ultimately the energy source for it is fossil fuels.

Hydrogen is not a net producer of energy. Rather, it is a carrier of energy. You have to create hydrogen gas in the first place. For example, you have to use electricity to separate water into hydrogen and oxygen. So although electric and fuel cell cars give us the promise of a smog-free future, there is still the problem that the energy they use comes largely from burning coal. Ultimately, we b.u.mp up against the first law of thermodynamics: the total amount of matter and energy cannot be destroyed or created out of nothing. You can"t get something for nothing.

This means that, as we make the transition from gasoline to electricity, we need to replace the coal-burning plants with an entirely new form of energy.

NUCLEAR FISSION.

One possibility to create energy, rather than just transmit energy, is by splitting the uranium atom. The advantage is that nuclear energy does not produce copious quant.i.ties of greenhouse gases, like coal- and oil-burning plants, but technical and political problems have tied nuclear power in knots for decades. The last nuclear power plant in the United States began construction in 1977, before the fateful 1979 accident at Three Mile Island, which crippled the future of commercial nuclear energy. The devastating 1986 accident at Chern.o.byl sealed the fate of nuclear power for a generation. Nuclear power projects dried up in the United States and Europe, and were kept on life support in France, j.a.pan, and Russia only through generous subsidies from the government.

The problem with nuclear energy is that when you split the uranium atom, you produce enormous quant.i.ties of nuclear waste, which is radioactive for thousands to tens of millions of years. A typical 1,000-megawatt reactor produces about thirty tons of high-level nuclear waste after one year. It is so radioactive that it literally glows in the dark, and has to be stored in special cooling ponds. With about 100 commercial reactors in the United States, this amounts to thousands of tons of high-level waste being produced per year.

This nuclear waste causes problems for two reasons. First, it remains hot even after the reactor has been turned off. If the cooling water is accidentally shut off, as in Three Mile Island, then the core starts to melt. If this molten metal comes into contact with water, it can cause a steam explosion that can blow the reactor apart, spewing tons of high-level radioactive debris into the air. In a worst-case cla.s.s-9 nuclear accident, you would have to immediately evacuate perhaps millions of people out to 10 to 50 miles from the reactor. The Indian Point reactor is just 24 miles north of New York City. One government study estimated that an accident at Indian Point could conceivably cost hundreds of billions of dollars in property damages. At Three Mile Island, the reactor came within minutes of a major catastrophe that would have crippled the Northeast. Disaster was narrowly averted when workers successfully reintroduced cooling water into the core barely thirty minutes before the core would have reached the melting point of uranium dioxide.

At Chern.o.byl, outside Kiev, the situation was much worse. The safety mechanism (the control rods) were manually disabled by the workers. A small power surge occurred, which sent the reactor out of control. When cold water suddenly hit molten metal, it created a steam explosion that blew off the entire top of the reactor, releasing a large fraction of the core into the air. Many of the workers sent in to control the accident eventually died horribly of radiation burns. With the reactor fire burning out of control, eventually the Red Air Force had to be called in. Helicopters with special shielding were sent in to spray borated water onto the flaming reactor. Finally, the core had to be encased in solid concrete. Even today, the core is still unstable and continues to generate heat and radiation.

In addition to the problems of meltdowns and explosions, there is also the problem of waste disposal. Where do we put it? Embarra.s.singly, fifty years into the atomic age, there is still no answer. In the past, there has been a string of costly errors with regard to the permanent disposal of the waste. Originally, some waste was simply dumped into the oceans by the United States and Russia, or buried in shallow pits. In the Ural Mountains one plutonium waste dump even exploded catastrophically in 1957, requiring a ma.s.sive evacuation and causing radiological damage to a 400-square-mile area between Sverdlovsk and Chelyabinsk.

Originally, in the 1970s the United States tried to bury the high-level waste in Lyons, Kansas, in salt mines. But later, it was discovered that the salt mines were unusable, as they already were riddled with numerous holes drilled by oil and gas explorers. The United States was forced to close the Lyons site, an embarra.s.sing setback.

Over the next twenty-five years, the United States spent $9 billion studying and building the giant Yucca Mountain waste-disposal center in Nevada, only to have it canceled by President Barack Obama in 2009. Geologists have testified that the Yucca Mountain site may be incapable of containing nuclear waste for 10,000 years. The Yucca Mountain site will never open, leaving commercial operators of nuclear power plants without a permanent waste-storage facility.

At present, the future of nuclear energy is unclear. Wall Street remains skittish about investing several billion dollars in each new nuclear power plant. But the industry claims that the latest generation of plants is safer than before. The Department of Energy, meanwhile, is keeping its options open concerning nuclear energy.

NUCLEAR PROLIFERATION.

Yet with great power also comes great danger. In Norse mythology, for example, the Vikings worshipped Odin, who ruled Asgard with wisdom and justice. Odin presided over a legion of G.o.ds, including the heroic Thor, whose honor and valor were the most cherished qualities of any warrior. However, there was also Loki, the G.o.d of mischief, who was consumed by jealousy and hate. He was always scheming and excelled in deception and deceit. Eventually, Loki conspired with the giants to bring on the final battle between darkness and light, the epic battle Ragnarok, the twilight of the G.o.ds.

The problem today is that jealousies and hatreds between nations could unleash a nuclear Ragnarok. History has shown that when a nation masters commercial technology, it can, if it has the desire and political will, make the transition to nuclear weapons. The danger is that nuclear weapons technology will proliferate into some of the most unstable regions of the world.

During World War II, only the greatest nations on earth had the resources, know-how, and capability to create an atomic bomb. However, in the future, the threshold could be dramatically lowered as the price of uranium enrichment plummets due to the introduction of new technologies. This is the danger we face: newer and cheaper technologies may place the atomic bomb into unstable hands.

The key to building the atomic bomb is to secure large quant.i.ties of uranium ore and then purify it. This means separating uranium 238 (which makes up 99.3 percent of naturally occurring uranium) from uranium 235, which is suitable for an atomic bomb but makes up only .7 percent. These two isotopes are chemically identical, so the only way to reliably separate the two is to exploit the fact that uranium 235 weighs about 1 percent less than its cousin.

During World War II, the only way of separating the two isotopes of uranium was the laborious process of gaseous diffusion: uranium was made into a gas (uranium hexafluoride) and then forced to travel down hundreds of miles of tubing and membranes. At the end of this long journey, the faster (that is, lighter) uranium 235 won the race, leaving the heavier uranium 238 behind. After the gas containing uranium 235 was extracted, the process was repeated, until the enrichment level of uranium 235 rose from .7 percent to 90 percent, which is bomb-grade uranium. But pushing the gas required vast amounts of electricity. During the war, a significant fraction of the total U.S. electrical supply was diverted to Oak Ridge National Laboratory for this purpose. The enrichment facility was gigantic, occupying 2 million square feet and employing 12,000 workers.

After the war, only the superpowers, the United States and the Soviet Union, could ama.s.s huge stockpiles of nuclear weapons, up to 30,000 apiece, because they had mastered the art of gaseous diffusion. But today, only 33 percent of the world"s enriched uranium comes from gaseous diffusion.

Second-generation enrichment plants use a more sophisticated, cheaper technology: ultracentrifuges, which have created a dramatic shift in world politics as a result. Ultracentrifuges can spin a capsule containing uranium to speeds of up to 100,000 revolutions per minute. This accentuates the 1percent difference in ma.s.s between uranium 235 and uranium 238. Eventually, the uranium 238 sinks to the bottom. After many revolutions, one can remove the uranium 235 from the top of the tube.

Ultracentrifuges are fifty times more efficient in energy than gaseous diffusion. About 54 percent of the world"s uranium is purified in this way.

With ultracentrifuge technology, it takes only 1,000 ultracentrifuges operating continuously for one year to produce one atomic bomb"s worth of enriched uranium. Ultracentrifuge technology can easily be stolen. In one of the worst breeches of nuclear security in history, an obscure atomic engineer, A. Q. Khan, was able to steal blueprints for the ultracentrifuge and components of the atomic bomb and sell them for profit. In 1975, while working in Amsterdam for URENCO, which was established by the British, West Germany, and the Netherlands to supply European reactors with uranium, he gave these secret blueprints to the Pakistani government, which hailed him as a national hero, and he is also suspected of selling this cla.s.sified information to Saddam Hussein and to the governments of Iran, North Korea, and Libya.

Using this stolen technology, Pakistan was able to create a small stockpile of nuclear weapons, which it began testing in 1998. The ensuing nuclear rivalry between Pakistan and India, with each exploding a series of atomic bombs, almost led to a nuclear confrontation between these two rival nations.

Perhaps because of the technology it purchased from A. Q. Khan, Iran reportedly accelerated its nuclear program, building 8,000 ultracentrifuges by 2010, with the intention of building 30,000 more. This put pressure on other Middle East states to create their own atomic bombs, furthering instability.

The second reason the geopolitics of the twenty-first century might be altered is because another generation of enrichment technology-laser enrichment-is coming online, one potentially even cheaper than ultracentrifuges.

If you examine the electron sh.e.l.ls of these two isotopes of uranium, they are apparently the same, since the nucleus has the same charge. But if you a.n.a.lyze the equations for the electron sh.e.l.ls very carefully, you find that there is a tiny separation in energy between the electron sh.e.l.ls of uranium 235 and uranium 238. By shining a laser beam that is extremely fine-tuned, you can knock out electrons from the sh.e.l.l of uranium 235 but not from that of uranium 238. Once the uranium 235 atoms are ionized, they can be easily separated from uranium 238 by an electric field.

But the difference in energy between the two isotopes is so small that many nations have tried to exploit this fact and have failed. In the 1980s and 1990s, the United States, France, Britain, Germany, South Africa, and j.a.pan attempted to master this difficult technology and were unsuccessful. In the United States, one attempt actually involved 500 scientists and $2billion.

But in 2006, Australian scientists announced that not only have they solved the problem, they intend to commercialize it. Since 30 percent of the cost of uranium fuel comes from the enrichment process, the Australian company Silex thinks there could be a market for this technology. Silex even signed a contract with General Electric to begin commercialization. Eventually, they hope to produce up to one-third of the world"s uranium using this method. In 2008, GE Hitachi Nuclear Energy announced plans to build the first commercial laser enrichment plant in Wilmington, North Carolina, by 2012. The plant will occupy 200 acres of a 1,600-acre site.

For the nuclear power industry, this is good news, since it will drive down the cost of enriched uranium over the next few years. However, others are worried because it is only a matter of time before this technology proliferates into unstable regions of the world. In other words, we have a window of opportunity to sign treaties to restrict and regulate the flow of enriched uranium. Unless we control this technology, the bomb will continue to proliferate, perhaps even to terrorist groups.

One of my acquaintances was the late Theodore Taylor, who had the rare distinction of designing some of the biggest and smallest nuclear warheads for the Pentagon. One of his designs was the Davy Crockett, weighing only fifty pounds, but capable of hurling a small atomic bomb at the enemy. Taylor was such a gung ho advocate of nuclear bombs that he worked on the Orion project, which was to use nuclear bombs to propel a s.p.a.ceship to the nearby stars. He calculated that by successively dropping nuclear bombs out the end, the resulting shock wave would propel such a s.p.a.cecraft to near the speed of light.

I once asked him why he got disillusioned with designing nuclear bombs and switched to working on solar energy. He confided to me that he had a recurring nightmare. His work on nuclear weapons, he felt, was leading to one thing: producing third-generation atomic warheads. (First-generation warheads of the 1950s were huge and difficult to carry to their targets. Second-generation warheads of the 1970s were small, compact, and ten of them could fit into the nose cone of a missile. But third-generation bombs are "designer bombs," specifically tailored to work in various environments, such as the forest, the desert, even outer s.p.a.ce.) One of these third-generation bombs is a miniature atomic bomb, so small that a terrorist could carry it in a suitcase and use it to destroy an entire city. The idea that his life"s work could one day be used by a terrorist haunted him for the rest of his life.

GLOBAL WARMING.

By midcentury, the full impact of a fossil fuel economy should be in full swing: global warming. It is now indisputable that the earth is heating up. Within the last century, the earth"s temperature rose 1.3 F, and the pace is accelerating. The signs are unmistakable everywhere we look: *The thickness of Arctic ice has decreased by an astonishing 50 percent in just the past fifty years. Much of this Arctic ice is just below the freezing point, floating on water. Hence, it is acutely sensitive to small temperature variations of the oceans, acting as a canary in a mineshaft, an early warning system. Today, parts of the northern polar ice caps disappear during the summer months, and may disappear entirely during summer as early as 2015. The polar ice cap may vanish permanently by the end of the century, disrupting the world"s weather by altering the flow of ocean and air currents around the planet.