The average inhabitant of the world is Chinese. Not exactly, but close. 

Seven out of eight Chinese are needed to work on farms. Agriculture in the U.S. employs less than five percent of the work force -- and produces a surplus. 

The difference is in petroleum consumption. And that difference will get smaller. 

Automobiling is less common in China than in the U.S. This difference, too, is one of petroleum consumption. Won't this difference also decrease? 

Interesting to guess where farming and automobiling will eventually average out worldwide. 

One thing is plain. We all gotta eat.

Solar energy takes a few minutes to reach the earth where it activates the green plants. A few months later, grain can be harvested, and a few weeks after that, fed to chickens. A few hours later, the chickens lay eggs, which a few days later are served scrambled to a bicyclist. A few minutes later, the bicyclist pedals off to work or school using that same solar energy. 

Not too shabby. 

Yet. in "First World" countries, agriculture has gotten to be petroleum intensive. The same may be true of the "Second World," for that matter. In the more centralized economies, the fraction of the total labor force devoted to agriculture has declined from 50% to less than 5% during the past century. 

There has necessarily been a compensating increase in dependency on fossil resources for food production as well as for industrial output. 

Thus. while it takes about 10 calories of energy to produce -- and deliver -- a calorie of grain, only about 2 of those calories come from the sun. 

The rest come from petroleum -- in the form of Diesel fuel to drive farm machinery for cultivation, planting, harvesting, and to operate irrigation pumps. There are petroleum-based chemicals in pesticides, fertilizers, and preservatives -- not to mention packaging materials. Finally, the petroleum cost for transportation and distribution of agricultural products -- grain as well as eggs -- must also be counted, along with refrigeration and cooking. 

If the bicyclist happens to want ham along with those scrambled eggs, the petroleum-content of her/his breakfast is increased by another factor. It takes about 18 calories of grain to make a calorie of pork

Four-fifths of the total weight of a bicycle with rider is payload -- the rider. 

When a fully loaded jet plane takes off on a transcontinental trip, only one-fifth of its total weight is payload. The rest is divided about equally between air-frame weight and fuel load. Thus. two-fifths of the jet's gross weight is kerosene. 

Regulations require enough fuel on board to reach the destination and, if necessary, to fly on to an alternate aerodrome, plus 45 minutes beyond that -- all at full cruise power settings. So, for a five-hour flight, the plane would take off with upwards of seven hours of fuel in its tanks. 

After a normal landing, the plane would still have about two hours of fuel remaining. Five-sevenths of the fuel weight would have been burned off or two-sevenths of the plane's total take-off weight (five-sevenths times two-fifths equals two-sevenths, as they used to teach fourth graders). Okay, let's divide that number, two-sevenths, which represents the weight of fuel burned, by one-fifth, which represents the payload. We get ten-sevenths or approximately 1.4, which says the plane bums 1.4 pounds of fuel for each pound of payload. 

Now suppose that you're a passenger on this transcontinental flight. Let the weight of you and your luggage together be 210 pounds. Multiplying that number by ten-sevenths, the ratio of fuel burned to payload, yields the weight of fuel burned on your behalf for the journey -- 300 pounds. Since a gallon of kerosene weighs six pounds, about 50 gallons will be burned to get you from, say, Boston to San Francisco, a distance of some 3,000 miles. If we do just one more division we get 60 miles-per-gallon -- quite splendid. 

Actually, that's 60 passenger-miles-per-gallon, about the same as a car with two passengers in it, getting only 30 miles-per-gallon. 

Not quite splendid after all.
 
 

The space shuttle is about the same size as a medium size jumbo jet -- when it lands. And its wings use Bernoulli's Principle. 

A venerable law of nature, Bernoulli's Principle mandates that the local pressure of a fluid varies inversely with its velocity. The airfoil on the shuttle develops "lift" just that way, the same as a DC-10 or a Piper Tri-Pacer. 

When it takes off, though, the space shuttle operates entirely differently. The thing is designed to shoot straight up. In order to do so, its engines must develop sufficient thrust at lift-off to overcome the weight of the entire shuttle ensemble. Bernoulli is no help. 

The jet airplane, like the bicyclist, only needs enough thrust to overcome drag, the lift being provided by the action of the airfoil. The ratio of lift-to-drag is typically ten-to-one; therefore, only one-tenth the thrust is required for the jet to take off compared to the space shuttle. Bernoulli does all the rest -- the aerodynamic equivalent of "mechanical advantage." 

As with all other things that move through fluids -- birds and buses, bikes and barracuda -- there's always the invisible enemy, drag. What if there were not? 

You might postulate a certain airliner flying along on a transcontinental trip, its engines developing a thrust equal to about one-tenth the weight of the aircraft. Without drag to hold it back, that thrust would cause the plane to accelerate -- at about one-tenth of a "g." This means the plane would increase its speed about 2.2 MPH each second. 

After two hours, the speed would be about 17,000 MPH. That's fast enough to put the whole airliner into orbit! Why, the pilot could shut off the engines and coast indefinitely, on a flight of unlimited distance. Just like the shuttle. 

Our calculations did leave out one thing, oxygen. Eliminating air resistance in our thought experiment also removed the air itself. How will our jet engines "breathe?" 

Jet engines inhale huge quantities of air, of which only 20% is oxygen. For each pound of fuel burned, an engine needs about fourteen and a half pounds of air to get enough oxygen to support combustion. Well, let's do what the shuttle does, carry our own supply of pure oxygen -- about three and a quarter pounds of oxygen for each pound of kerosene. 

We now must redesign our hypothetical airliner to include oxygen tanks. It'll mean a heavier airframe (spaceframe?) and more fuel consumed to haul the oxygen -- and to haul the additional fuel. We might continue to burn kerosene, or we can switch to hydrogen like the shuttle -- the ultimate consumption of fossil resources being about the same for either fuel. 

For a given payload, our spaceliner's take-off weight will have to be about seven and a half times larger than the air-breathing jet, and fuel consumption will go up by a factor of three and a half. Thus, instead of consuming two hours of fuel to reach orbital velocity, it'll take seven. 

Notice, that's about equal to the total fuel load carried by today's jets. 

So, the next time you see an airliner taking off for a long flight, you might recall that all those people on board could be placed into earth orbit with the same amount of fossil fuel that will be burned in flying across the country -- were it not for the invisible enemy of the bicyclist, wind resistance.

Never underestimate the power of alliterative dogma. 

Nuclear weaponry is far more efficient than conventional tools of war -- if your criterion is getting more "bang for the buck." 

Armies and Navies and Air Forces are labor intensive. Imagine the fixed expenses for administration and facilities. The overhead associated with training alone must be staggering. Logistics are horrendously complicated and costly. And what about their demands on petroleum resources? The actual costs for explosives are but a small increment. 

By way of comparison, take your standard ICBM. 

Here you get a picture of high-efficiency indeed. There's the missile itself out there in the Mid-West, all charged up, quivering in its silo, ready to go anywhere in the world. Not many people around, though. The only activity occurs at a shift change. You see some saluting and such, then a key on a lanyard is ceremonially handed over. The on-duty crew members march down a tunnel into a reinforced bunker to stand their watch, while the others, now off-duty, amble off to the parking lot, thence to their nearby homes for supper. 

The destructive power in that nuclear missile is more than all the trinitrotoluene armies can muster, by orders of magnitude. That's efficiency. 

If your alliterative criterion is something like "defense for the dollar," however, nuclear weaponry does not fare well at all. 

The law of unintended consequences prevails. 

The expression "mutual assured destruction" (MAD) is all too self-descriptive. The central doctrine embodied in MAD derives from a plurality of matched nuclear capabilities (the M in MAD). Also matched mentalities, wouldn't you say? All parties have to be equally scared. More precisely, world leaders have to be equally scared on behalf of their respective constituencies. 

Once "assured" (the A in MAD) by balanced nuclear weapons technologies, there seems little point in escalating. Gaining an advantage, ironically, confers no advantage. Instead, getting the parties to be unequally scared is exactly what nobody wants. 

Along comes a proposal, say, for a new orbiting anti-ballistic missile system. What could be less offensive than that? 

If such a missile "screen" is perceived to be really effective, though, the side without the system has an immediate incentive for offensive action -- before the new defense system can be deployed by the other side. Moreover, once in place, those space lasers, or whatever they are, will remove one country's D in MAD. Almost. No defense system claims to be perfect. 

How about the "counter-force" strategy? Rather than targeting missiles for the destruction of cities and citizens, aim them instead at missile silos and bunkers. 

Fine, except this forecloses the option of absorbing a first strike before retaliation. The other side has to set a hair trigger. "Launch on warning," it's called. Otherwise, they won't have anything to retaliate with. The counter-force missiles, accordingly, would strike only empty silos. They might not be the only things destroyed, however. You get all these thermonuclear blasts going off and who knows what will actually happen. 

Bang for the buck -- we've got plenty of that already. 

Defense for the dollar -- in the long run, are we really getting "defense" from our nuclear weaponry? 

Mutual assured miscalculation is more like it. 

There must be a better way to save petroleum.

A word on behalf of the wide-bodied macho-van drivers of America. 

They don't all have pot bellies. Nor tobacco-stained teeth. They're neither ignorant nor malicious. They would never intentionally crowd a bicyclist off the road. 

It's good to get that cleared up.

In the post-petroleum age, we will indeed have to do without some things. Not all of what we give up will cause regret. 

Take crime, for one thing. Some types will become harder to pull off.  Particularly those that require get-away cars. 

Take war, for another thing. It's hard to put on a really big war without using lots of petroleum. Ironically, petroleum is one of the best reasons to have a war, too. Beats hearts and minds. 

The recent war in Southeast Asia was no exception, even though it was won by the side with the bicycles. Not too surprising, when you think about it. Bicycles are potent logistical weapons. They're unexcelled for moving troops efficiently and silently through rugged terrain. A bicycle can carry as much as 500 pounds of military supplies, if the rider doesn't mind occasionally walking along beside it. And bikes are cheap. They can wreak havoc with an enemy's economy.  Imagine deploying easily hidden $100 equipment as the targets for $10,000 bombs. 

In the post-petroleum age, both sides will have bicycles. Wars won't be as big. But they'll be more evenly matched.

There will be no visitors to earth from outer space. Here's why. 

For even the most advanced civilization, the effort to get here is enormous. Whoever "they" are, you can be sure they'll be mighty selective about where they're heading before setting off. They'll go for the most likely places to find what they want. Resources, for example. Knowledge, for another. 

What resources do we have that interstellar voyagers might want? Precious metals come first to mind. Not very likely. They'd doubtless find what they need closer to home, within their own planetary system. Besides, would it make sense for them to attempt a trans-galactic raid on Fort Knox? Uranium is ruled out for a different reason. They've already found out, just as we will eventually, that fission is not a particularly desirable energy alternative. They're intelligent, remember. 

To space tourists, the plants and animals on earth would be interesting, but more for gardens and zoos than for farms and feed-lots. A long way to go for houseplants and pets. 

The most likely substance extraterrestrials would seek is, of course, petroleum. After all, it takes millions of years to produce really good stuff. Anybody intelligent would want the "noble substance" for the many things that can be made out of it: high-strength-to-weight materials, medicines and fabrics, lubricants and lenses.
 
 

Far-off star-trekkers have already found out about earth's oil by eavesdropping on our radio broadcasts, some dating back more than 60 years. The earliest estimates of our petroleum reserves would have been deciphered a generation ago. By now, however, they'd have figured out -- even if we haven't -- that the supplies will run out before they could get here, even at warp speed. 

Which leaves knowledge. Space visitors might want to come here to meet intelligent life, peruse our museums, ride our bicycles. Only trouble is, they already know what we're doing with our petroleum. 

Burning it. What an intergalactic embarrassment!  It sure puts in doubt the existence of intelligent life here. 

No, they're not going to be especially interested in visiting earth. Nor in meeting us.