Atacama Desert

The Atacama is a desert in Chile, in South America.

It is one of the driest places in the world. Some towns get almost no rain at all. The ground is sand, rock and salt. It is a cool desert, not a very hot one.

The Atacama Desert stretches about 1,000 to 1,100 kilometers along northern Chile, up to the border with Peru. Low coastal mountains run along its western side, and the foothills of the Andes rise to the east. In between lie salt flats, gravel slopes, some sand dunes and, farther east, tall volcanoes.

The Atacama is one of the driest places on Earth. The World Meteorological Organization (WMO) lists Arica, in the far north, as the place with the lowest average yearly rain in South America: just 0.76 millimeters. Yet it is a cool desert: the average summer temperature in the coastal city of Iquique is only about 19 °C.

Britannica describes the Atacama as a cool, arid region of northern Chile, 1,000 to 1,100 km long, whose limits are not exactly fixed: it lies mainly between the south bend of the Loa River and the mountains separating the Salado and Copiapó basins, and continues north to the Peruvian border. The Cordillera de la Costa, about 1,500 m high with peaks to 2,000 m, ends in sea cliffs over 500 m high with no coastal plain. Inland, a raised depression forms the Tamarugal Plain above 900 m; to the east, beyond the Cordillera Domeyko, volcanic cones exceed 4,900 m, and the Atacama Plateau reaches 4,000 m along the borders with Argentina and Bolivia.

The WMO's table of climate extremes (2025) gives Arica the lowest average annual precipitation in South America, 0.76 mm over 59 years, and the world's longest recorded dry period, 172 months from October 1903 to January 1918. NASA notes that parts of the desert may receive as little as about 1 cm of rain in a decade.

In the driest places, tiny living things hide under the ground and inside rocks.

Higher up, there are salty lakes. Three kinds of flamingos feed and rest there.

In the driest middle of the Atacama, NASA explains, there is very little water and strong ultraviolet light from the Sun, so most life there is microbes, tiny living things, living underground or inside rocks. That is why scientists study the Atacama to learn how life might survive on Mars.

Higher up, in the salt flats and lagoons near the Andes, there is more life. Three kinds of flamingos, the Andean, James's and Chilean flamingos, feed and nest there. In the summer of 2024, Chile's national forest service, CONAF, counted 18,078 flamingos in and around the Los Flamencos National Reserve, including many young birds.

NASA's Atacama Rover Astrobiology Drilling Studies (ARADS) describe the hyperarid core as a place where scarce water and intense ultraviolet radiation confine most life to microbial colonies underground or inside rocks. Despite being warmer than Mars, its extreme dryness and soil chemistry are remarkably Mars-like, and from 2016 to 2019 NASA Ames teams tested the K-REX2 rover there, with a drill able to reach 2 m through salt, rock and soil to search for biomarkers.

At the desert's eastern edge, high-Andean salt flats and lagoons support Andean flamingos (Phoenicoparrus andinus), James's flamingos (P. jamesi) and Chilean flamingos (Phoenicopterus chilensis). CONAF's 2024 summer census covered 15 lagoons, salt flats and wetlands across about 1,100 km of routes in and around the Los Flamencos National Reserve and counted 18,078 flamingos, over half at the Salar de Pujsa (7,573) and Salar de Tara (5,392), both priority Ramsar sites; the high share of juvenile James's and Andean flamingos suggests the lagoons are important feeding grounds.

People live in the Atacama in towns and green oases.

They use river water to grow lemons, potatoes and other food. Big mines there dig up copper.

In the Atacama, people farm in river oases, the green places where rivers bring water. Britannica says the original people of the region were the Atacameño. Today lemons grow at the oasis of Pica, crops grow beside the salt marshes at San Pedro de Atacama, and water from the Loa River waters potato and alfalfa fields near Calama. Local Lickan Antay communities, such as Toconao and Talabre, also help CONAF count flamingos.

The desert is rich in minerals. In the 1800s, people began mining sodium nitrate, and before World War I Chile had a world monopoly on it. Ports and railroads were built to carry it. Today the region earns most from copper mining at Chuquicamata.

Britannica names the Atacameño as the region's original inhabitants, distinct from the Aymara to the north and the Diaguita to the south; CONAF's 2024 census credits participation by Lickan Antay communities of Toconao and Talabre. Oasis farming supports only a few thousand traditional cultivators: lemons at Pica, varied crops at San Pedro de Atacama, potatoes and alfalfa irrigated from the Loa near Calama.

In the 19th century the desert's sodium nitrate deposits were contested by Chile, Bolivia and Peru. Britannica records that after the War of the Pacific (1879 to 1883) the Treaty of Ancón (1883) gave Chile permanent ownership of sectors previously held by Peru and Bolivia, the latter losing its whole Pacific coastline. Until World War I nitrate was a chief source of Chile's wealth, with up to 3 million tons extracted in some years, until synthetic nitrogen fixation shrank the market. Copper mining at Chuquicamata, in the Calama basin, is now the region's chief source of revenue.