Cars should get better mileage! Cars shouldn't cause global warming! And that goes double for SUVs!! It appears that most Americans agree with those statements. It is just that they don't understand how to get it to happen. Maybe they really do understand, but are in a state of denial. It seems that Americans think that the federal government should just require manufacturers to make cars that get better mileage. It is simple.

The problem is that it isn't simple. Perhaps it is the past experience with a gutless Congress and President when the CAFÉ (Corporate Average Fuel Economy) requirements came into effect. They just said that manufacturers were required to make cars that got better than x miles per gallon. Actually they said that the fleet average of the cars (not trucks) that the manufacturer made should deliver x miles per gallon.

What does that mean? That means that a manufacturer must make a bunch of small cars that get good mileage to make up for a bunch of bigger (higher profit!) cars that get less than x miles per gallon. Oh, by the way, that "x miles per gallon" was 21.6 for 2006 and is 22.2 for 2007. And that is the "old way" of calculating and measuring miles per gallon, not the "new way" that shows lower numbers on 2007 window stickers.

The problem is that this tells the manufacturers what they need to make, not what customers will actually buy. Also it indirectly tells the American consumer that if the government tells GM to make Hummers that get 40 miles per gallon, that GM could magically do it. The problem is that with today's engineering technology, it isn't possible and almost any cost. It certainly is impossible at a cost that a consumer would pay -- and it is impossible even with tomorrow's technology.

What happens to a manufacturer who makes a fleet of cars that don't meet the CAFÉ average number? Each car is taxed directly at purchase time. It's on the window sticker. If the individual car achieves over 22.5 miles per gallon, there is no tax. But if it gets between 21.5 and 22.5, there is a $1000 tax added to the purchase price (that is paid back to the IRS). That tax is graduated to ever higher numbers as the car gets worse mileage. For those that get between 12.5 and 13.5, the number is $6400, and if it is worse than that, the tax is $7700. If you look at a Ferrari, Bentley, or a car like that, you will find numbers like this on every price sticker. Since these cars are almost always ones with price numbers with six digits, it really makes little difference to the purchaser.

What is the "right way" of increasing mileage for the average kind of car? It is very obvious to anyone other than a politician. Just use the same kind of tax on all cars with the magic number something like 30 or 40 miles per gallon. It depends on where the incentive should be. Cars with average mileages better than the "magic number" could get a tax rebate. This could even apply to annual registrations, if you really wanted to motivate American consumers to buy cars that get good mileage.

But you say, then why would a manufacturer care what the mileage a car got if the consumer paid for the poor mileage. That's obvious. The manufacturer with an average 4-door sedan that got 30 miles per gallon would sell a whole lot more than a manufacturer who made a similar sedan that got 20 miles per gallon. Either the manufacturer would have to quote a lower price to compensate for the tax, or just sell fewer cars.

The other obvious, but politically unacceptable, approach is to just raise the gas tax. $4 or $5 per gallon gasoline would very quickly motivate American consumers to buy smaller better mileage cars. Even the threat of $3.50 gas a couple of months ago did that. The market for SUVs went down drastically -- even here in Los Angeles. Since gas is inching up in that direction again, will the sale of small cars increase and big SUVs decrease even more. Probably.

This is the approach the Europeans and Japanese have used for years. You see very few big cars or SUVs on the streets of Europe. That's mostly because of the $7 per gallon gas. But also you could argue it is because of the traffic volume and very narrow streets of European cities.

But these days, any kind of tax increase puts the fear of death into a politician's heart (and brain). They can't even propose taxes that are good because just saying the word "tax" automatically starts their opponents' negative publicity machines. So that eliminates the easiest and most direct way of getting much higher mileage cars on the road in the United States -- and coincidentally reduce our need for imported oil.

But what about those of us who are more worried about global warming than importing oil? That means thinking about the emission of carbon dioxide or as it is commonly abbreviated CO₂. While the Bush administration has been denying that global warming exists, many scientists are showing very clear data that shows that it does. It is fact that the U.S. contributes some 45 percent of the global emission of carbon dioxide and has 30 percent of the world's cars on the road, but just 5 percent of the population. Those statistics come from looking at the total emission of carbon dioxide in metric tons. The "don't look at the U.S." people quote numbers that look at tons of carbon dioxide per dollars of GDP. With a very high GDP in the U.S., it makes us "look better" when compared to the rest of the world...

The Europeans have a much smaller population than the U.S (I'm considering the EU) and contribute much less carbon dioxide than the U.S. to the world total, but they are much more concerned about the world's problem. The EU has mandated that their member countries reduce carbon dioxide emissions.

I do remember that you and I emit carbon dioxide as we breathe, but vehicles emit a lot more. Naysayers tell us that cattle produce more carbon dioxide than people do, mostly in flatulence. Okay, but we, as the world population, make too much carbon dioxide and we are eliminating forests that convert carbon dioxide back into oxygen, thus making the problem worse.

Britain taxes (yearly) "company cars" based on carbon dioxide emissions. All cars manufactured after 1998 are covered. The tax is based on the list price of the car and the amount of carbon dioxide (in grams per kilometer) coming out of the tailpipe. The tax for a 2006 car that puts out 200 g/km is based on 27 percent of the list price. That 27 percent amount (the basis for the tax) is applied to 2002 cars that emit 225 g/cm carbon dioxide.

So how much carbon dioxide comes out of the tailpipe of a typical car? I picked some typical 2007 BMW models. Note also some are diesel powered that only are sold in Europe right now.

	Fuel	CO2 g/km
320d Coupe	diesel	145
530d	diesel	176
530i	gasoline	178
335d Coupe	diesel	200
335i Coupe	gasoline	228
Z4 3.0i	gasoline	217
335i Sedan	gasoline	231
335i Convertible	gasoline	238
X3 3.0i	gasoline	248
550i	gasoline	246
550i*	gasoline	260
650i	gasoline	267
750i	gasoline	271
760Li	gasoline	327
M5*	gasoline	357

All of the BMWs in the table are 6-speed automatics except the ones with the asterix. The 550i has a 6-speed manual and, of course, the M5 has the SMG 7-speed. It is very obvious that performance comes at the price of more carbon dioxide out the tailpipe. It is also clear that diesels get better fuel mileage, but not an awful lot better in the carbon dioxide department.

The problem in Europe is that the car makers got into a CAFÉ-like agreement with the EU voluntarily. They agreed to meet a fleet-average of 140 g/km next year. Unfortunately the Germans won't make it. The agreement was made in 1998 and they were progressing toward their goal very well until the Europeans discovered SUVs. The public demand for them was something that the manufacturers couldn't resist. In 2005, the manufacturers closest to the goal were Fiat, Citroën, Renault, Ford, and Peugeot. Looking at the list, it's obvious that the French and Italians are putting the Germans' feet to the fire. Even Chancellor Angela Merkel had to rush in to defend the German manufacturers.

The German industry claims that the biggest part of the problem is the EU itself as it has mandated many safety standards since the 1998 agreement that have caused the weight of the cars to increase. It is also certain that nobody will know if they meet the quoted standard until 2010 when the measurements are done. They are owning up to the problem now, though, because they are quite certain they won't make the 130 g/km goal. But now the EU is setting the goal at 120 g/km for 2012 which probably isn't any more realistic.

Will science save us by inventing a solar powered artificial plant that converts carbon dioxide into oxygen? Maybe. The problem, however, is what happens to the carbon. Sure, one could strip off the oxygen chemically, but you end up with a pile of carbon that nobody wants. On the other hand, maybe with all that very pure carbon, an industry would develop that makes carbon fiber products cheaply.