ABSTRACT
The societies which are found in drylands in the twentieth century are the result of evolution over time. With some groups these changes have been very slow over hundreds of years and have resulted in a society which is in equilibrium with its environment. Such societies can have different forms, with economies based on hunting and gathering, pastoral farming or sedentary agriculture. In other cases, changes have been so rapid in modern times that entirely new economies have been produced which are dependent not on local agricultural produce (as with the case of traditional societies), but on fossil-fuel subsidies instead.
