The western margins of South America are rimmed by one of the world’s longest and highest mountain ranges, the Andes, a giant wall that extends unbroken from Tierra del Fuego near the continent’s southern tip in Chile to northeastern Venezuela in the far north as if to reaffirm the continent’s northward and eastward orientation. The Amazon Basin, South America’s other main physiographic feature, dominates its center north; this enormous humid-tropical amphitheater is drained by the great Amazon River, which is supplied by numerous significant tributaries.
The Brazilian Highlands, which comprise most of Brazil southeast of the Amazon Basin, the Guiana Highlands, which are located north of the lower Amazon Basin, and the cold Patagonian Plateau, which covers the southern third of Argentina, make up the remainder of the continent.
Physiography of the South American Continent
In the early nineteenth century, the famous German explorer and scientist Alexander von Humboldt, one of the founders of the modern science of geography, started on his epic travels in northern South America.
The fourth-largest continent, South America, stretches from the Tierra del Fuego archipelago south to the Gulf of Darién in the northwest. South America’s three main physical divisions are mountains and highlands, river basins, and coastal plains. While highlands and river basins often flow in an east-west orientation, mountains and coastal plains typically run north to south.
Tectonic forces have shaped the primary landforms of this enormous territory to form an overall pattern of highlands to the west and lowlands to the east. The population of South America remains concentrated around the continent’s edges. The interior is sparsely populated for the most part, but areas of it are presently seeing significant development.
The arid desert habitat of South America’s coastal lowlands climbs to the untamed alpine biome of the Andes highlands in just a few hundred kilometers. The Amazon River Basin in the continent is characterized by thick tropical rainforest, whereas extensive grasslands characterize the Paraná River Basin.
South America has one of the greatest diversities of plant and animal species of any continent in the world.
The Andes, which make up most of South America’s mountain range, is also the longest in the globe. The range cover is approximately 8,850 kilometers (5,500 miles). The Andes run the length of South America’s westernmost coast, from its southernmost point to its northernmost shore. Over 4,500 meters (15,000 feet) tall peaks are numerous, and many of them are volcanic.
Aconcagua, the tallest mountain in the Andes, spans the boundary between Argentina and Chile and is 6,962 meters (22,841 ft) tall. The highest mountain outside of Asia is Aconcagua.
The Andes are also characterized by high plateaus. For instance, the altitude of the Peruvian and Bolivian altiplano is roughly 3,700 meters (12,300 feet). Lower-elevation plateaus and untamed glaciers make up Argentina’s and Chile’s Patagonia area.
The Brazilian Highlands and the Guiana Highlands are South America’s two main highland regions outside of the Andes. The Brazilian Highlands are a region of low mountains and plateaus that rise to an average height of 1,006 meters south of the Amazon River in Brazil (3,300 feet). Between the Amazon and Orinoco Rivers lie the Guiana Highlands. Southern Venezuela, French Guiana, Guyana, northern Brazil, and a small area of southeast Colombia are all covered by the densely wooded plateau known as the Guiana Highlands.
South American coastal plains can be found on the western, Pacific coasts of Peru and Chile as well as the northeastern, Atlantic coast of Brazil. Northeastern Brazil’s coastal lowlands are incredibly arid. Moist sea breezes are pushed away from the coastal plains by the Brazilian Highlands, which function as a wedge.
Additionally, the western coastal plains are quite arid. The Andes Mountains to the east and the chilly Peru Current to the west have confined them. The Chilean and Peruvian Pacific coasts receive chilly water from the Peru Current. Thermal inversion is caused by the cold surface water, which causes chilly air at sea level and stable, warmer air higher up. At low elevations, thermal inversion causes a thick layer of clouds.
A portion of the western coastal plain includes the Atacama Desert. The Atacama is regarded as the world’s driest area. Some areas of the Atacama Desert have never had rain in recorded history, and the average annual rainfall is only approximately 1 millimeter (0.04 inches).
On the world map, if the Russia/Central Asia realm is the widest in east-west extent, South America is the longest measured from north to south. (Within South America, no other country is more emblematic of this elongated geography than Chile, averaging only about 150 kilometers [90 mi] in width but 4000 kilometers [2500 mi] in length.).
Because of its vast latitudinal range, which extends from around 12°N to 56°S, this region has a wide range of climates and vegetation. When you combine this with significant elevation fluctuation from west to east, it’s easy to see why South America has such a diverse spectrum of natural environments.
From a wide tropical zone in the north to a small sub-Arctic zone in the south, South America is divided. Four climatic divisions are possible: tropical, temperate, desert, and cold.
More than half of the continent is covered by tropical climates, which include both tropical rainy climates and tropical wet and dry climates. The Amazon River region, Colombia’s northeastern coast, and its Pacific coast all experience tropical wet weather. The average daily temperature in the area is 30 degrees Celsius (86 degrees Fahrenheit), with relatively little seasonal change. The Chocó region of Colombia, for instance, receives more than 800 centimeters (315 inches) of rain annually, even though the average annual rainfall is just 262 centimeters (103 inches).
The temperate regions of the continent are found south of the Tropic of Capricorn and at mid-altitudes in the Andes mountains. Compared to tropical climates, temperate regions have a wider variety of temperatures and colder winters.
Numerous industrial crops and cattle are raised in the temperate temperatures of South America. In temperate regions, corn is grown everywhere, and in the Pampas, soybeans are a more and more profitable crop.
These climates range from extremely hot to severely cold, but they all get relatively little precipitation. Agriculture output is tough as a result. But in the arid oases, crops that require a lot of irrigation, such as rice, and cotton, are cultivated.
The southernmost points of Chile and Argentina as well as the Andes‘ highest points have cold climates. The typical yearly temperature in a cold environment is below 10 degrees Celsius (50 degrees Fahrenheit). Long dry seasons and strong winds define the climatic conditions in these regions.
Major Climate Change impact in South America
In the Caribbean and Latin America, the warming trend continued in 2021. Between 1991 and 2021, the average rate of temperature increase was 0.2°C/decade, as opposed to 0.1°C/decade between 1961 and 1990.
Glacier Retreat or Shrinking of Glaciers:
Since the 1980s, with a negative mass balance trend of -0.97 m water equivalent per year for the 1990–2020 monitoring period, the tropical Andes have lost 30% or more of their land. In Peru, some glaciers have lost more than 50% of their original extent. The risk of water shortage for the Andean people and ecosystems has grown as a result of glacier retreat and the related loss of ice mass.
Rise in Sea Level:
particularly along the Atlantic coast of South America south of the equator (3.52 0.0 mm per year, from 1993 to 2021), in the region continues to increase at a greater rate than globally. A considerable section of the population, which is concentrated in coastal areas, is in danger due to sea level rise because it would contaminate freshwater aquifers, erode shorelines, flood low-lying communities, and increase the likelihood of storm surges.
As of 2021, the “Central Chile Mega Drought” persisted for 13 years, making it the longest drought to have affected the area in at least a decade.
This drought has accelerated a drying trend and put Chile at the forefront of the region’s water issue. A multi-year drought in the Parana-La Plata Basin, the worst since 1944, also afflicted sections of Bolivia, Paraguay, and central-southern Brazil.
Increase in the Hurricane’s Frequencies:
The 2021 Atlantic Hurricane Season was the sixth straight above-normal Atlantic Hurricane Season and had 21, including seven hurricanes, the third-highest number of named storms on record. Some of these storms had an immediate effect on the area.
Changing Rainfall Pattern:
Floods and landslides were caused by the extreme rainfall in 2021, which set records in numerous locations. There were significant losses, including thousands of homes destroyed or damaged, tens of thousands of casualties, and hundreds of thousands of displaced people. An estimated US$ 3.1 billion in damages were caused by floods and landslides in the Brazilian states of Bahia and Minas Gerais.
(* All the above discuss impacts of climate change in South America are based on IPCC and WHO reports.)
El Niño and La Niña Effect on the South American Continent
Trade winds sweep west along the equator in the Pacific Ocean under typical conditions, carrying warm water from South America toward Asia. Upwelling is the process by which cold water rises from the deep to replace that warm water.
These typical circumstances are disrupted by the opposing climatic patterns of El Nio and La Nia. The El Nio-Southern Oscillation (ENSO) cycle is the name given to these events by scientists. Both El Nio and La Nia have the potential to affect weather, wildfires, ecosystems, and economics on a worldwide scale. El Nio and La Nia episodes normally last nine to twelve months, although can may persist for years. In general, El Nio and La Nia occurrences happen every two to seven years, although they don’t always happen at the same time.
Circulation during El Nino
Trade winds deteriorate during El Nio. The west coast of the Americas receives a rush of warm water from the east.
El Nio is Spanish for Little Boy, sometimes known as the Christ Child. In the 1600s, South American fishermen were aware of stretches of exceptionally warm Pacific Ocean water. El Nio de Navidad was the full term they used because it usually peaks in December.
El Nio has a big impact on our weather. The Pacific jet stream shifts south of its neutral location due to the warmer seas. The northern U.S. and Canada are seeing drier and warmer weather than typical as a result of this change. However, these times are wetter than typical and have more flooding in the Southeast and Gulf Coast regions of the United States.
El Nio has a significant impact on marine species off the Pacific coast as well. Under typical circumstances, upwelling delivers cold, nutrient-rich water from the depths to the top. Upwelling weakens or ceases entirely during El Nio. There is less phytoplankton off the shore when the nutrients from the deep are absent. This has an impact on fish that consume phytoplankton, which has an impact on everything that consumes fish. Tropical animals like yellowtail and albacore tuna may enter regions that are usually too cold as a result of the warmer seas.
Circulation during La Nino
La Nia is Spanish for “Little Girl.” La Nia, which has the opposite impact of El Nio, is also known as El Viejo, anti-El Nio, or simply “a chilly occurrence.” Trade winds are much stronger than usual during La Nia occurrences, bringing more warm water into Asia. Upwelling increases off the west coast of the Americas, sending cold, nutrient-rich water to the surface.
The Pacific’s chilly waters force the jet stream northward. Drought in the southern United States and severe rainfall and flooding in the Pacific Northwest and Canada are often the results of this. Wintertime temperatures are often warmer in the South and colder in the North during a La Nia year.