Atacama Desert

Atacama Desert, arid region in northern Chile, bounded on the west by mountains along the Pacific Coast and on the east by the Andes Mountains. With rainfall occurring only two to four times a century, the Atacama Desert is one of the driest regions in the world. The lack of rain is a result of thermal inversion. Cold waters brought from the Antarctic by the Humboldt Current release cold air at the surface, forcing warmer air higher up. The inversion produces fog in the desert but little rain. Consequently, vegetation in the Atacama is extremely sparse, with the exception of a few irrigated oases. The inversion also keeps temperatures low in the Atacama, despite the region’s proximity to the equator. For example, the Chilean cities of Antofagasta and Santiago have comparable temperatures, despite the fact that Antofagasta, located in the Atacama region, is 1,700 km (1,000 mi) closer to the equator.

The area came under hot dispute during the late 19th century when Bolivia, Peru, and Chile fought for control of the region’s valuable nitrate and copper deposits. Chile emerged victorious from the War of the Pacific (1879-1883), and drew considerable wealth from the Atacama region’s natural resources. The introduction of synthetic nitrates led to a decline in the systematic extraction of nitrate after World War I (1914-1918). Efforts were transferred to copper mining, now the region’s chief revenue source. Area, about 363,000 sq km (about 140,000 sq mi).