companies looking to keep prices low will have to move some production closer to consumers. Globe-spanning supply chains Brazilian iron ore turned into Chinese steel used to make washing machines shipped to Long Beach, Calif., and then trucked to appliance stores in Chicago make less sense today than they did a few years ago.To avoid having to ship all its products from abroad, the Swedish furniture manufacturer Ikea opened its first factory in the United States in May. Some electronics companies that left Mexico in recent years for the lower wages in China are now returning to Mexico, because they can lower costs by trucking their output overland to American consumers.Neighborhood EffectDecisions like those suggest that what some economists call a neighborhood effect putting factories closer to components suppliers and to consumers, to reduce transportation costs could grow in importance if oil remains expensive. A barrel sold for $125 on Friday, compared with lows of $10 a decade ago. If prices stay at these levels, that could lead to some significant rearrangement of production, among sectors and countries, said C. Fred Bergsten, author of The United States and the World Economy and director of the Peter G. Peterson Institute for International Economics, in Washington. You could have a very significant shock to traditional consumption patterns and also some important growth effects.The cost of shipping a 40-foot container from Shanghai to the United States has risen to $8,000, compared with $3,000 early in the decade, according to a recent study of transportation costs. Big container ships, the pack mules of the 21st-century economy, have shaved their top speed by nearly 20 percent to save on fuel costs, substantially slowing shipping times. The study, published in May by the Canadian investment bank CIBC World Markets, calculates that the recent surge in shipping costs is on average the equivalent of a 9 percent tariff on trade. The cost of moving goods, not the cost of tariffs, is the largest barrier to global trade today, the report concluded, and as a result has effectively offset all the trade liberalization efforts of the last three decades. The spike in shipping costs comes at a moment when concern about the environmental impact of globalization is also growing. Many companies have in recent years shifted production from countries with greater energy efficiency and more rigorous standards on carbon emissions, especially in Europe, to those that are more lax, like China and India.But if the international community fulfills its pledge to negotiate a successor to the Kyoto Protocol to combat climate change, even China and India would have to reduce the growth of their emissions, and the relative costs of production in countries that use energy inefficiently could grow. The political landscape may also be changing. Dissatisfaction with globalization has led to the election of governments in Latin America hostile to the process. A somewhat similar reaction can be seen in the United States, where both Senators Barack Obama and Hillary Rodham Clinton promised during the Democratic primary season to re-evaluate the nations existing free trade agreements. Last week, efforts