Pushing the climate frontier

摘要

When nineteenth-century explorer William Gilpin travelled across the Great Plains, the expanse that covers much of the central and western United States, he marvelled at the "great pastoral region" the dry climate of which was "favorable to health, longevity, intellectual and physical development". Great cities could be built there, he imagined, taking advantage of the wealth of local resources -rivers, forests and even gold. Geologist John Wesley Powell saw things differently. Moving from the humid east to the arid west would affect agricultural practices, occupations, social interactions and political customs, he contended. Dry-land agriculture could not support a large population; any towns built in the west would need appropriate designs, irrigation and resource management. A controversy erupted.