He noted that the Northern, cold regions like the U.S., Britain, Europe and Japan had large, well-developed economies while the hot, tropical countries were less well endowed—the so-called equatorial paradox. Huntington ascribed the differences in economic performance to differences in climate. Some economists are uncomfortable with this idea.
According to Huntington, these differences in economic performance also affected political structures—tropical states tend to have unstable political histories.
Other factors in this model affecting economic performance are access to the sea and the presence of raw materials like oil. Singapore, for example, occupies a key position as a seaport, while the wealth of Saudi Arabia depends almost entirely on oil.