The climate of South America is extremely diverse due to geographic, atmospheric and oceanic factors. In the specific case of Chile and Peru, the oceanic factor is essential due to the so-called Humboldt current.
But What is its origin and what effects does it have on the climate? We will talk about all this and much more in this special.
What is Humboldt's stream?
This current, also known as the Peruvian current, It is a marine current caused by the rise of deep waters and, therefore, very cold, that occurs on the western coasts of South America. It was described by the German naturalist Alexander von Humboldt in his work "Journey to the equinoctial regions of the New Continents" published in 1807.
It is the most important cold water stream in the world, and also one of those that has more notable effects on the climate, in this case, of the coasts of Chile and Peru due to the combined effects of the movement of the earth's rotation and the centrifugal force of oceanic waters in the equatorial zone.
Upon emerging from the depths of the coast, its waters have a very low temperature, about 4ºC, and flow in a north direction along the western coast of South America, parallel to the coastline until reaching the latitude of the equator. . For this reason, the temperature of these waters is between 5 and 10ºC lower than it should be, taking into account its location and proximity to the equator.
Cold waters are very nutritious: specifically, contain high levels of nitrates and phosphates from the seabed, on which phytoplankton can feed, which, in turn, can reproduce rapidly and become part of the diet of zooplankton, on which larger animals and also humans will feed.
If we talk about the climate, even though it is arid and desert, thanks to the Humboldt current some very hardy plants, such as cacti in the Sonoran desert, can live due to abundant mists and fogs that are condensed on the shores.
However, sometimes the current does not emerge, and north winds carry warm waters south. When this happens, a warm current, known by the name of El Niño, replaces it causing a rise in temperatures of about 10ºC, which supposes a diminution of the flora and the marine fauna, and a threat for the survival of those terrestrial animals that feed on it, such as birds.
Effects on climate
As we have said, the climate of the coasts of South America is generally arid, desert. Due to the latitude, it should be tropical and subtropical, but because its waters are between 5 and 10ºC lower than they should be, the atmosphere cools.
Thus, in what should be a place of lush rain forests and with pleasant temperatures, in the areas that are in contact with this current we find relatively cold coastal deserts, like the Atacama, whose temperatures range from -25ºC to 50ºC, and which is also the driest on Earth. Despite being close to the equator, the rains are very scarce and only a few plants and animals can survive.
Some examples are:
- Plants: Ricinus communis, Shizopetalon tenuifolium, Senecio myriophyllus, Copiapoa
- Animals: sea lions, foxes, long-tailed snake, caterpillars, praying mantis, scorpion
Does climate change influence the Humboldt current?
Unfortunately yes. Cold and alkaline waters have a high level of oxygen, thanks to which many animals can live in them, but water that is nearly deoxygenated has a tendency to spread as temperatures rise, so that some have had to go elsewhere; However, others, such as the Peruvian anchovy, have been favored and have been able to reproduce in such a way that today they are abundant in the fishing boats.
Peruvian and Chilean waters they are acidifying due to global warming. And as a consequence of this process, even the climate of the coasts of South America could one day change, putting the ecosystem at risk.
In addition, the El Niño phenomenon has intensified and there are experts who say that, as the planet warms, the chaos it will cause will be greater, since it not only affects the climate causing significant droughts and floods, but also to the crops. As a consequence, the price of food will become more expensive as it will be more difficult to produce.
So far, the worst El Niño was in 1997, but that of 2016 is almost identical. With warmer waters, meteorological phenomena such as hurricanes or tornadoes will become more intense.
Did you know the Humboldt current?