International trade has devolved in the 20th century into climate- and resource-controlled exchange between temperate and tropical zones, and intra-temperate zone trade dominated by technology. Nations of temperate zones have been highly inventive of trade-influencing devices. Prospects are that ineffectual efforts to ease trade barriers multilaterally will give way to bilateral and regional trade compacts, which will mark the early 21st century. Later in the century, raw material shortages will scramble relations among nations, including those of trade. Technology yet to be developed could affect the balance among nations, even dramatically.