China's fuel use is WAY less than the US. Yes, they have billions of people, but they aren't all driving cars, they walk and use bicycles (mostly because they have to). Its not a small country either.
How many cars do we own? In the US, as of 2003, there are about 475 cars per 1000 people. In China, there are a whopping 6 cars per 1000 people. Even if each of those cars puts out 10 fold more pollution than the average US car then their output from automobile use is still tremendously less than ours.
China has 5 times as many people as the US (that estimate is a bit high, but it works for these quick calculations). Even adjusted for that population difference, they still have about 6% as many cars as the US has. The average Chinese person uses 827 kilowatt hours of electricity in the time it takes the average American to use 12,322 kilowatt hours. Again, adjusted for population differences, they only use 30% of the electricity we use. Their powerplants can be 3 times dirtier than ours and STILL make less pollution than we do. Plus, a huge amount of their power comes from hydroelectric systems (which actually do their own sort of environmental damage, but since we are talking about air pollution ATM, they count as pretty clean).
Yes, we need to be concerned about the pollution outputs of rising world industries like China and India, but we still consume the lions share of energy, and put out the lions share of pollution.
Now, I'm not saying CARB is always right, in fact, having lived in Cali, I know they are usually misguided, but pollution controls themselves are not misguided. Now if you live in a rural area, you might not have a good understanding of what tremendous pollution problems are like, but you will. Despite all the pollution lowering advances made by car makers, the fact remains that every year Americans drive more miles than the previous year. The increase in miles driven cancels out much of the pollution control measures. Its like people buying low-fat cookies, and then eating the whole box.
Not to mention the fact that while per-gallon emissions are down, fuel economy gets worse every year. In fact, the highest average fuel economy US vehicles had was in 1987, with a value around 22.1 MPG. Its down to 20.8 in 2003, and had held steady for something like 8 years. All our advances are not amounting to a decrease in fuel use, they are amounting to an INCREASE in fuel use, along with an increase in CO2 output.
The point I'm trying to make is that the US has a problem. These numbers are simple facts, and show that car manufacturers and average car buyers are not interested in lowering consumption or pollution, and that if there is going to be a light at the end of the tunnel, it will be through a concerted effort to raise efficiencies and lower pollution further. Just because you don't see smog in your rural sky doesn't mean your climate is not being affected by global warming today, and for years to come.
Now, I'm not saying I know HOW we should fix these problems, and I'm not saying CARB knows how they should be fixed either. But I know a few things I can do as an individual, like bike when I can, drive my scooter (at 100MPG and fuel injected to produce lower emissions than modern cars) when its just myself, and use biodiesel vehicles when moving more than just myself. If everyone did what they could to lower their output, we wouldn't need silly laws, problem is, left to their own devices, the average american would just consume faster and faster until we all passed out dead in our hummers on the freeway. Now, silly laws aren't usually the solution, just public education, but in crisis areas like LA, something had to be done..
Hopefully with ULSD fuel and increased availability of biofuels, modern diesels can make a comeback in the US. Diesel electric hybrids make a lot of sense (and should have preceded the gas-hybrid, IMHO).
Whew. Back to work.
-Sam
References:
http://www.dallasfed.org/research/swe/2003/swe0305a.html
http://www.eia.doe.gov/emeu/rtecs/chapter3.html
http://www.epa.gov/otaq/fetrends.htm
http://www.epa.gov/otaq/cert/mpg/fetrends/420s04002.pdf