Environmental determinism, also sometimes known as "climatic determinism" or "geographical determinism," is the view that the the fate of human societies and the development of human cultures is predominantly determined by environmental, climatic, and geographical features beyond human control, rather than by social conditions or individual human decisions.
To a certain extent almost everyone accepts that environmental factors such as the availability of natural resources, access to water, and natural barriers to trade and commerce affect the development of human societies and cultures, but most people still make significant room for the role of human decision-making and more complex social interactions in their theories. Environmental determinists, however, tend to overlook other factors entirely, or only pay them token regard, and tend to view human social development is largely or exclusively stimulus-response behavior.
Perhaps not surprisingly, "environmental determinism" is a label not always happily accepted by environmental determinists themselves, as few people want to admit they are that reductionist in their views, and tends to be applied to their work by critics and outside observers.
A classic example of environmental determinism is the argument, prevalent in Great Britain and Japan, that "island nations" (or shimaguni), have unique and similar cultural traits shaped by their isolation from continental societies. Particularly in Japan, other forms of environmental determinism are still quite popular as well, including arguments that Japan's "unique" culture is also a product of its many mountains or its distinct four seasons, although enviromental determinist arguments have been advanced at various periods to explain the development almost every nation and society on Earth.
A famous recent example of environmental determinism in the West is of course the writings of Jared Diamond, who although he denies that he is an environmental determinist, in fact consistently argues that the relative success of Western, European culture in World History is almost entirely attributable to environmental factors.