thumb|upright=1.5|Humboldt Current
The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America. It is an eastern boundary current flowing in the direction of the equator, and extends offshore. The Humboldt Current is named after the German naturalist Alexander von Humboldt even though it was discovered by José de Acosta 250 years before Humboldt. In 1846, von Humboldt reported measurements of the cold-water current in his book Cosmos. This is highly uncharacteristic of tropical waters, as most other regions have temperatures measuring above . Upwelling brings nutrients to the surface, which support phytoplankton and ultimately increase biological productivity. It accounts for roughly 18-20% of the total worldwide marine fish catch. The species are mostly pelagic: sardines, anchovies and jack mackerel. The system's high productivity supports other important fishery resources as well as marine mammals (eared seals and cetaceans) and seabirds. Periodically, the upwelling that drives the system's productivity is disrupted by the El Niño-Southern Oscillation (ENSO) event, often with large social and economic impacts.
The Humboldt has a considerable cooling influence on the climate of Chile, Peru and Ecuador. It is also largely responsible for the aridity of the Atacama Desert in northern Chile and coastal areas of Peru and also of the aridity of southern Ecuador. Marine air is cooled by the current and thus is not conducive to generating precipitation (although clouds and fog are produced).
Physical oceanography
thumb|upright=1.9|The presence of the Humboldt Current and its associated wind shear makes for conditions that inhibit the formation of [[tropical cyclones.<br/>(Worldwide tropical cyclone tracks, 1945–2006.)]]
The trade winds are the primary drivers of the Humboldt Current circulation.]]
The productivity of the Humboldt Current System is strongly affected by El Niño and La Niña events.