Environmental determinism is the theory that the physical environment, including the climate, sets hard limits on human society. It claims patterns of environmental change or geographical difference as a way to understand trajectories of human and social development and, by so doing, explain why some societies flourish while others languish in poverty or even collapse. The fundamental argument of the environmental determinists was that aspects of physical geography, particularly climate, influenced the psychological mind-set of individuals, which in turn defined the behavior and culture of the society that those individuals formed.

The theory of environmental determinism dates back to the 15th century. Plato and Aristotle believed that the climate contributed to the Greeks being highly developed early on, as compared to other civilizations in hotter or colder climates. The Greek geographer, Strabo, also had similar ideas and wrote about climate affecting the development of human beings at the physiological level. This concept was developed further later on and proposed the idea that environmental factors were the origin of different skin colors.

In modern times, environmental determinism rose to popularity during the 19th and 20th centuries. Following Charles Darwin's On the Origin of Species, German geographer Friedrich Rätzel proposed that evolutionary biology and our environment play the most prominent role in our development as a species. This ideology eventually spread to the United States and remained popular there until the 1940s, when it was accused of supporting racism and imperialism. Blame Sachs, while an economist at Harvard, repackaged old-fashioned environmental determinism as the “ecology of underdevelopment.” As he wrote in a 1999 article in The Economist, “If it were true that the poor were just like the rich but with less money,” he wrote, “the global situation would be vastly easier than it is. As it happens, the poor live in different ecological zones, face different health conditions and must overcome agronomic limitations that are very different from those of rich countries. Those differences, indeed, are often a fundamental cause of persisting poverty.”

Here Sachs, a key advisor to United Nations Secretary-General Ban Ki-Moon, makes the crackpot but quintessential environmental determinist argument: the redistribution of wealth won’t resolve global inequality. Why? Because the geographical and unequal distribution of affluence and poverty is not a result of unequal power relations but rather is a function of complex geographic and climatic dynamics that have nothing whatsoever to do with histories of colonial conquest and capitalist expansion. The argument, of course, relies on a premise that ignores histories of conquest— what Karl Marx, in reference to colonialism, called primitive accumulation.