The rule of thumb I saw was that it took more oil/energy to move shipped goods 50miles from the port than it took to get it from China by ship. And that's with time=money; you can cut oil/energy usage by cutting ship speed.

We will still have global trade long after we have no personal car transport.

The cost in energy for the global economy is due to more than just shipping finished goods trans pacific.
1. Energy is used in shipping raw materials like copper from S. America to China, scrap steel from US to China, wood from Canada to China.
2. Energy is used in shipping within China raw materials and finished goods, often by truck as the railway network is still small compared to US.
3. More energy used in processing of raw materials in less than efficient plants/factories because the energy costs are subsidized and cheaper in China.
4. The energy for China's economy is increasing relying on coal for both electric power and transport (electric railways and soon electric cars), causing increased production of AGW gases.

US has the luxury of being more self sufficient in both raw materials and energy sources for its electricity (coal, ng, uranium) than China. In the US these things need go only maybe 1000 miles by rail instead of going 20,000 miles by sea to/from China and maybe 500 to 1000 miles by truck within China.

Not if you layer on enough carbon offset taxes and cap&trade fees. And how high do those taxes and fees need to be? Well, carbon cycle models show humans contribute 3% of all CO2 released into the biosphere annually. So if you wanted to make a significant dent in that 3%, say a 2/3 dent, how high would new taxes and fees need to be for you, for me and for all our neighbors to reduce our driving, home heating and the like by 2/3 (67%)? That's going to be a tremendous amount of government taxes and fees added to the current cost of transport. That would certainly motivate me to relocate manufacturing operations closer to my local markets. The result of such draconian measures would need to be coordinated world-wide in order to reduce CO2 emissions by net 2%. What do you think would be the impact on world economies? societies? living standards? What do think would be the net reduction in CO2 accumulation in the atmosphere over 5 years? 10 years? 30 years? 50 years? Here's the scale of the pay off:

http://www.forexyard.com/reuters/popup_reuters.php?action=2009-05-28T222...