Generally overlooked in its specificity, the South Atlantic past is habitually subsumed in the North Atlantic history. However, the South Atlantic has its own historical, nautical, geopolitical and cultural characteristics, highlighted by a growing number of researchers over the last two decades.¹ Such elements have been asserted over three distinct periods of the South Atlantic. The first, that the age of its emergence, begins in 1500, when the fleet of the Portuguese Admiral Álvares Cabral, en route to India, reached the South American coast in the region of the current State of Bahia, Brazil. His vessels then returned to sea towards Cape Town and the Indian Ocean, undertaking the first latitudinal crossing of the South Atlantic.

This period finishes in the middle of the 19^th century, with the end of the bilateral slave trade between Brazil and Africa (1850), and the opening of the Suez Canal (1869). Designed for steamships, the Canal shortened the journey between the West and East and put an end to the Age of Sail. The supremacy of the North Atlantic over the ocean was thus achieved, leading to the disappearance of the South Atlantic system.

The independence of African nations, particularly those of the former Portuguese colonies (1973-1975), and the downfall of the Apartheid regime in South Africa (1991-1994), started the third period of the South Atlantic. At the beginning of the 21^st century, the South-South ties in the Atlantic reemerged within an international scenario radically modified by the end of the Cold War and the political and the economic affirmation of the sub-saharan countries.

The First South Atlantic: the Ethiopic Ocean 1500-1850

During the Age of Sail, the nautical system engendered by the winds and the currents of the South Atlantic gyre improved connections between South American and African ports.² Molded by the anticyclone of Saint Helena and with its northern limit on the meteorological equator, located between five and ten degrees north of the terrestrial equator, this system is distinctive from the Caribbean and, more generally, the North Atlantic, as we will see below. In addition to sailing between the Iberian ports and South America, vessels from Bahia, Recife, Rio de Janeiro and, less often, from Buenos Aires, had direct exchanges with several African Atlantic seaports.

In the same time, Portuguese vessels on the Lisbon-Goa-Macau route, which sailed the great oceanic route to the West, called at the port of Bahia. For the first time in history, tropical cultures of the Americas, Africa, and Asia were connected, as well as the equatorial zones encompassing the richest biomes on the planet, the Amazonian Basin, the Congo Basin, and Southeast Asia. The globalization of tropical biomes points out the drastic growth in the number of plants recorded by European botanists, which rose from 1000 to around 6000, in the 16^st century.³

As inter-oceanic migrations and massive deportation of Africans to the Americas began, the export agriculture (sugarcane, tobacco, cotton, coffee) extended through the American Atlantic, while cassava, maize and peanuts were transplanted from the Caribbean and South America to the Island of São Tomé, Elmina (currently in Ghana), and Mpinda (south of the mouth of the Congo), from where its farming spread to the Gulf of Guinea and West Central Africa. Adapted to poor soils, without natural predators in Africa, cassava is currently grown from the Sahel to Angola and Mozambique. Although reliant on regular irrigation, the cultivation of corn has equally spread in Africa, owing to its high productivity. At present, cassava crop up as the most important primary source of calories for Sub-Saharan populations, while maize became the most eaten cereal in Africa.

It is worth to note that São Tomé emerged as a major hub for the transfer of edible plants from various continents. It is through their acclimatization on this island and their transplantation to other areas that the coconut tree (Oceania), bananas (Asia/Africa), and cocoa (the Americas), amongst other plants, became pan-tropical crops.

From Africa to the Americas stands out the transplantation of cereals such as sorghum, fruits like watermelon, vegetables and legumes such as the gumbo (quiabo, okra), as well as the bean's subspecies called black-eyed pea in the Southern United States and West Indies, niébé (Wolof) in Francophone Africa or feijão-fradinho and mucunha (from the Macua nkuny) in Brazil. Besides the alimentary sphere, the Sub-Saharan culinary transposed and adapted to regions of the Americas represented an identity affirmation, serving as an offering to the gods of the Afro-American pantheon.

Alongside the diffusion of Afro-American religions, the cult of the image of Our Lady of Aparecida (Nossa Senhora Aparecida), represented with black skin, began near the route crossed by enslaved Africans and colonists heading from Rio de Janeiro to the gold mines of Minas Gerais, at the beginning of the 18th century. Later revered as Patroness of Brazil, the Black Madonna's devotion highlights the role of Afro-Brazilians in the formation of society. By contrast, similar cults existing in other Latin American countries show the Mediatrix Mother with an Iberian or Amerindian face, as is in the case in Mexico with the Virgin of Guadalupe, the Virgin of Guápulo in Ecuador, Our Lady of Copacabana in Peru and Bolivia, the Virgin of Luján in Argentina, and Our Lady of Caacupe in Paraguay.

In the last quarter of the eighteen-century, confronting Portuguese preeminence on the Slave Trade on both sides of the South Atlantic, Spain reacted, creating the Vice-Royalty of Río de la Plata whose capital was Buenos Aires (1776). In addition to the mining region of Potosí, in today's Bolivia, the Patagonia, part of the Pacific coast and the River Plate and its hinterland, the new vice-royalty included the African island of Fernando Po and Annobón, as well as the slaving posts along the coasts of Cameroon and Gabon. In vain Madrid tried to break the Luso-Brazilian quasi-monopoly over the South Atlantic black slave trade.

Likewise, the Spanish authorities were confronted with the increased cruising of European rivals towards the Pacific along the Cape Horn route. Naval and diplomatic disputes began between French, British and Spanish which gave rise to the first Falkland/Malvinas crisis (1764-1776). Located in front of the Magellan Strait, the Falkland/Malvinas archipelago guards Drake Passage between Cape Horn and Graham Land, sole maritime routes of access to the Pacific until the opening of the Panama Canal (1914). At the end of the 18th-century, French and above all American and British whalers roamed the Falkland/Malvinas' waters and south of the River Plate, in search of sperm whales to meet the high demand for spermaceti. A waxy substance found in the heads of sperm whales, spermaceti was used in the manufacture of expensive candles and cosmetics. Tracking whales across the ocean, captains of New England and Europe provided geographers and cartographers with more precise knowledge about the South Atlantic's currents and winds. Using his own data and information collected by whalers from Nantucket, Massachusetts, the British oceanographer James Rennel mapped in 1832 the surface currents of the South Atlantic for the first time.⁴ According to the map published in London in 1763 by William Herbert, Rennel set the northern limits of the South Atlantic between 5 and 10 degrees north of the geometrical equator, in the intertropical convergence zone which defines the meteorological equator.

Encompassing the South of Senegambia and the Gulf of Guinea, such space is named, mainly in the Anglo-American maritime guides, Ethiopian Ocean, to emphasize the specificity of its winds and currents next to the North Atlantic's nautical system. The 1855 edition of The American Cyclopaedia, a well-known encyclopedia at the time, established a distinction between the North Atlantic, considered at the "Atlantic proper" and the "Ethiopian Ocean", that is, the maritime and nautical system located to the south of the geometrical equator.⁵

In the wake of the Battle of Trafalgar (1805), which opened a century long British maritime supremacy, the Royal Navy undertook a general offensive in the South Atlantic. Cape Town was seized in 1806 from the Dutch, while on the other side of the ocean, the British attacked the Spanish and Hispano-American forces in Buenos Aires (1806 and 1807) and Montevideo (1807). Subsequently, the British occupied the islands of Ascension, Santa Helena, and Tristan da Cunha. A naval base (1815-1922) and an air base (1942-) transformed Ascension into a key point in British control over the Cape route. Completing the South Atlantic guard, London proclaimed its sovereignty over the Malvinas/Falklands islands in 1833, expelling the Argentine garrison and creating an unsettled conflict with the Buenos Aires government.

By suggestion and naval help of the British government, the Portuguese court was transferred from Lisbon to Rio de Janeiro when French troops commanded by Junot invaded Portugal. Rio de Janeiro thus became the capital of the Portuguese Empire (1808-1821). Lord Strangford, the British ambassador to the Portuguese government between 1806 and 1815, organized the move of the Court to Rio de Janeiro and, from there, acted in the political and military maneuvers that enable Argentina's independence from Spain (1816). Prohibited after 1812 in the River Plate ports, the African slave trade intensified in Brazil, which became after its independence (1822) the chief exporting country of tropical products. The maintenance of the bilateral trade between Brazilian and African ports transformed Rio de Janeiro into the largest slave port in the Americas and collided with London's naval and diplomatic campaign to halt the Atlantic Slave Trade. It was not until 1850 that Britain managed to break the slave trade connections formed over three centuries between South American and African ports. In the same time, Argentina (1853), Brazil (1854), and later Uruguay established policies favoring European immigration. Similarly, the end of the Atlantic slave trade with South America instated in Angola the 'second colonial period' (1850-1974), according to the periodization proposed by Portuguese historians. In fact, the Portuguese colonial administration stimulated coffee, sisal and maize production, as well as diamond mining, in order to make Angola a 'new Brazil.' Altogether, these mutations intensified the North-South connections, bringing an end to the first South Atlantic.

Unlike other transcontinental maritime networks that emerged during the 16th century, such as the Antilles or the Indian Ocean, where the exchanges were not discontinued by the irruption of new regional powers, merchants or commodities, the bilateral navigation between Brazilian and African ports ceased abruptly in 1850, for a long period of time. Underlining the navigation and commercial emptiness of this area following the end of the African slave trade, a well-known British nautical guide included in 1883 an observation about the South Atlantic which had not existed in previous editions: "A large portion of the coast lying within the Southern tropics, and the absolutely barren nature of its eastern side, render the commerce in this vast area of water of very small importance compared with other seas of equal magnitude."⁶

The progression of steamships unified the ocean under the hegemony of the North Atlantic, turning obsolete the name Ethiopic Ocean, designating until then South Atlantic space and nautical system of the Age of Sail age and South-South trade.

The Second South Atlantic 1850-1975

The second South Atlantic evidences the divergent evolution of the South American and African sides of the ocean. During this period, the westernization of the South American side was accentuated. At the same time, European colonization in subequatorial Africa, essentially in Angola and South Africa, expanded before declining in the last decades of the 20th century under the rise of African independences and emancipation movements.

Sailing voyages along the South American coast and Cape Horn increased with the onset of British colonization in Australia and New Zealand (1834 and 1837) and the California Gold Rush (1849). In the same way, a regular Steamship line was opened in 1849 between Liverpool, Rio de Janeiro, Montevideo, and Buenos Aires. The speed and predictability of Steam voyages improved the incorporation of such ports to the London and European markets, transforming the economy and culture of the South American capitals. In Rio de Janeiro, the steam driven packet boats from Liverpool, called paquetes in Portuguese, generally with feminine names, arrived every 28 days in such a punctual manner that menstruation began to be called paquete.

The extension of telegraphic lines, initially with a regional and later a transoceanic scope, had distinct consequences in the South Atlantic. The near monopoly which the French news agency Havas enjoyed over the telegraphic system in Brazil and the Southern Cone, including Chile, reinforced Francophilia and the Franco-centrism in the region. Written in French, sent from Paris, via London, Lisbon, Madeira Islands, and Pernambuco, Havas' reports were transmitted along the regional telegraph lines of the South Atlantic coast, elongated in the 1880s towards Paraguay and Bolivia. On the opposite side of the South Atlantic, Cape Town and the South African telegraph network were connected to the British news organization Reuters, whose cables linked London to British India and the rest of Asia. South Africa's insertion in the circuits related to the United Kingdom was confirmed in 1910, when the country turned independent and remained within the Commonwealth until 1961. In sum, steam voyages and telegraph networks accentuated North-South connections, underpinning the geopolitical gap between the two sides of the South Atlantic.

That aside, South Africa's and Argentina's evolutions bore similarities, as highlighted by Philip D. Curtin in a pioneering essay.⁷ In Cape Town as well as in Buenos Aires the arrival of the telegraph and steamships networks matched the expansion of the railways and the military assault of the hinterland of the two countries. In Argentina, this movement led to the army's offensive called the "conquest of the desert" (1878), which resulted in the genocidal expeditions and deportation of thousands of Mapuches and other Native peoples of the Pampas and Patagonia, in order to allow new lands to Argentinians and immigrant ranchers, planters and sharecroppers. With the arrival of refrigerated steamships, mostly controlled by British companies, Argentina became a large meat exporter to Europe.

In South Africa, the discovery of the Kimberley diamond mines (1867) and gold mines in the Witwatersrand (1888), sparked the interest of Europeans and colonists, resulting in conflicts between the British, Zulus, and Afrikaners. Throughout the two Boer Wars (1880-1881 and 1899-1912), public opinion in South America republics was generally favorable to Transvaal and Orange, the two young republics which fought against Britain's monarchical colonialism. This was particularly the case in Buenos Aires⁸ and, to a lesser extent, in Rio de Janeiro press. As a result, after the British victory, almost 800 Boer families were welcomed by the Argentine government of General Roca, the former commander of the "conquest of the desert", and established themselves in Patagonia. Notwithstanding their feeble demographic weight in Argentina, the Boer presence led to the creation in Buenos Aires of the first South African Consulate-General in South America (1939), with jurisdiction over Uruguay and Brazil. In his travel account Patagonia, the novelist Bruce Chatwin recalled the fate of the Argentines of South African origin.⁹ Buenos Aires continued to grow, with its port overtaking Rio de Janeiro at the end of the 19th century. Rio de la Plata turn out to be the destination of tens of thousands of Europeans, especially Italians and Spaniards, who made Argentina, after the United States, the second country in the world with the most immigrants in the 1930's. Through the port of Valparaíso, troops of mules, and later, the Trans-Andean railway, operating between 1910 and 1980, linked Santiago de Chile to Mendoza and Buenos Aires, connecting the Chilean coast to Argentina.

The evolution of Brazil was rather different. Unique American monarchy from 1822 to 1889, Brazil, especially under the rule of Emperor Pedro II, took advantage of its dynastic and diplomatic ties with European thrones to display its singularity in relation to the Latin-American republics. Yet, notwithstanding its institutional and symbolic borrowing from European monarchies, the country remained strongly marked by slavery and Afro-Brazilian culture. In fact, Rio de Janeiro possessed in 1850 the highest urban concentration of enslaved in the Americas, with the latter representing 42% of its population.¹⁰ Depicted in the lithographs of Jean-Baptiste Debret from 1834 onwards, and afterwards in daguerreotypes and the first photographs, urban slavery formed the backdrop to the writings of travelers and the important Brazilian authors, from Machado de Assis to Aluísio de Azevedo.¹¹ The influx of Portuguese immigrants in the town at the end of the African slave trade (1850) changed the Carioca's accent to a more Lusitanian phonetic, but did not modify the distinctive Afro-Brazilian imprint of Brazilian Portuguese language.¹² Mocking this linguistic distancing which, at the time, and until the diffusion of Brazilian soap operas on Lisbon television channels, sounded incongruous to Portuguese ears, Bordalo Pinheiro draw a cartoon in which the emperor held a "Brazilian/Portuguese conversation guide" during Pedro II's first visit to Portugal (1872).¹³

In Argentina and Uruguay, Spanish language was in turn influenced by Italian dialects that gave rise to the Lunfardo. A mix of Lombardian dialects and colonial Spanish, the Lunfardo appeared as the slang of the underworld milieu in Rosario, Buenos Aires, and Montevideo. From these ports the Lunfardo spread to Santos and Rio de Janeiro, both through the sailors' jargon and the lyrics of the tangos.¹⁴

The westernization of the post-colonial culture was also propelled by European music and pianos. Since the middle of the 19th century the pianos were manufactured with better quality steel wires and cast-iron harmonic tops, instead of the wooden frames that warped in the tropics. Accordingly, pianos were able to conserve their musical qualities in South America. An ostentatious good, the European pianos became a must-have to affluent family's homes and theaters. Landed in ports, pianos were transported to the entire region on the backs of mules, called mulas pianeras (piano mules) in the River Plate region and Chile. Enthusiasm for the imported piano declined with the introduction of the phonographs and, later on, the radio and the phonographic industry in the 1920s. In the meantime, Afro-Latin music played in Buenos Aires, Montevideo, or Rio de Janeiro achieved great success and imposed itself as one of the principal South American's cultural and identity markers in the rest of the world.

The fall of the monarchy and the proclamation of the republic (1889) drove Brazil closer to the neighboring republics. Sponsored by Washington, Pan-American Conferences are organized aiming the harmonization of maritime and trade practices and laws among the countries on the continent. Alike Argentina and most Latin-American countries, Brazil adopted a federative presidential regime based on the United States constitutional model. Following meetings in Washington and Mexico City, Rio de Janeiro and Buenos Aires held Pan-American Conferences (1906 and 1910) and Congresses of American Jurists. In 1910, the Pan-American Union was created in Buenos Aires, which in 1948 became the Organization of American States, whose headquarters are in Washington. Parallel to the influence of the United States, there emerged in Brazil the feeling of belonging to Latin America and in 1900, for the first time, a Brazilian head of state was received in Buenos Aires for an official visit. Economic and demographic growth of Argentina, and above all of Buenos Aires, turned into a new magnet for international investments and European immigrants in the South Atlantic, cast a shadow on Brazil. Truly, The Argentinian capital, whose population rose from 780,000 inhabitants in 1895 to 2,034,000 in 1914, turn into the most populous and the richest Latin American metropolis. Since then Buenos Aires appears as the most European of the Latin American capitals. Most research about the urban modernization of Rio de Janeiro at the beginning of the 20^th century emphasize the inspiration of Haussmann's reforms in Paris, closely observed by the engineer and politician Pereira Passos, later mayor of the Brazilian capital (1902-1906), during his four years of studies in the French capital. However, rising competition from the port of Buenos Aires played its role in the government decision to modernize and cleanse the port and the city of Rio de Janeiro, and also of Santos, where the majority of immigrants from Europe, the Middle East, and Japan arrived in Brazil from the end of the 19th century onwards. In the meantime, the opening of the Panama Canal (1914) reduced the ships' transit in Brazilian and Southern Cone ports, reinforcing the predominance of North Atlantic ports throughout the ocean.

Occupying the longest national Atlantic coastline, Brazil had a strategic interest to the North Atlantic powers in the wake of the two World Wars. During the Great War the country joined the Allies in November 1917 and attended the Paris Peace Treaty and the Treaty of Versailles in 1919, while Argentina remained neutral through the conflict. In the Second World War, the distance between the two neighboring countries was more accentuated. Actually, Brazil was the only country in the region to enter the war on the Allies side. Besides, the United States Army built an American aeronaval base in Natal, north Brazil, which launched maritime and aerial operations in the South Atlantic and West Africa between 1943 and 1945. Having declared war on Germany and Italy in 1942, Brazil sent an expeditionary force of 27,500 soldiers who fought in the Italy campaign in 1944, while Argentina remained neutral until March 1945. Argentina was thus the only Latin American nation not to be invited to attend the Allies' Bretton Woods Conference, which created in July 1944 the international financial and monetary order of the post-war period.

On the other hand, thanks to the renown of its delegation, led by the economist Raul Prebisch, Argentina played a leading role in the establishment of CEPAL (Economic Commission for Latin America) in Santiago do Chile in 1948. Whereas Brazil's first Latin-Americanist move in the beginning of the 20th century, at a time largely dominated by Public and International Law, was undertook by jurists and constitutionalists, CEPAL's trained economists and sociologists, who shared a common interest in Latin America's present and future, achieved more effective governmental policies to the Latin American countries. Ultimately, CEPAL's scholars and researchers converted into political leaders and high-ranking civil servants in the region (such as the Brazilians Fernando Henrique Cardoso and Celso Furtado, or the Argentinian Aldo Ferrer) contributed to the negotiations and agreements that led to the creation of Mercosur (1985-1995).

That aside, the geopolitical context was profoundly altered in the half century that separates the CEPAL's foundation from the establishment of the Mercosur. South Atlantic countries were shaken by dictatorships and guerrillas while independence wars in Angola and Namibia, as well as the struggle against apartheid in South Africa threatened the colonial order in Central and Austral Africa. At this point, diplomatic contacts and cooperation between the authoritarian and colonial regimes on the two sides of the South Atlantic were envisioned. Thus, the idea of a diplomatic and military pact between Argentina, Brazil, Chile, the United Kingdom, Uruguay, the United States, and South Africa was thus evoked on several occasions in the second half of the 20^th century.

Meanwhile nationalist insurrections in the European colonies of Central and Southern Africa led South Africa to take more concrete measures. Hence, In South Africa diplomats and Navy commanders contacted high-ranking naval officers of Brazil and Argentina intending to establish a South Atlantic military alliance, similar to the NATO. Next to the visit of Marcelo Caetano, head of the Portuguese colonial government, to Brazil in July 1969, newspapers from Cape Town and Johannesburg announced the participation of Portugal in the creation of a South Atlantic Defense Pact. Moreover, at the beginning of the 1960's the Portuguese regime preempted Gilberto Freyre's Luso-Tropicalismo theory, claiming an alleged Portuguese aptitude to mend non-conflictual relations with its colonized peoples, in particular with Africans. Heralded by the Salazar regime, Luso-Tropicalismo epitomized the last avatar of the Portuguese colonial ideology.

The planned South Atlantic Defense Pact was unsuccessful due to litigation between Argentina and Chile over the Southern Andes border and the Anglo-Argentine conflict over the Malvinas. Brazilian and Argentinian diplomats also opposed the Defense Pact. Moreover, Brazil's diplomats contributed to cancel plans of joint Portuguese and Brazilian naval maneuvers along the Angola's coast, intended to put pressure on Angolan nationalist's guerrilla. Confirming its geopolitical orientation, Brazil was the first non-African nation to recognize, in November 1974, the Angola's independence under the pro-Soviet and pro-Castroist regime led by the MPLA's leader Agostinho Neto. In fact, during the presidencies of Janio Quadros and João Goulart (1961-1964), progressive Brazilian diplomats had already anticipated the advantages of direct relations with an independent Angola and advocated a rapprochement with Angolan and Lusophone African nationalists.

In South America, the Falkland/Malvinas War (1982) put the alliance between the dictatorships of the Southern Cone and Brazil under stress. While Brazil exhibited its neutrality to the belligerents, Chile openly supported the United Kingdom. In practice, Brazil, like Uruguay, maintained its traditional policy that recognizes Argentina's full sovereignty over the Malvinas archipelago. Later, in 2018, Chile also declared its support for Argentina. The redemocratization of South American countries, the independence of Angola and Namibia, and the end of apartheid in South Africa (1994) again modified the rules of the game in the South Atlantic.

The Third South Atlantic

In the 1980's and 1992's, the dictatorships of the southern South America and Brazil ended: in 1983 in Argentina, 1985 in Brazil, 1986 in Uruguay, 1990 in Chile and 1992 in Paraguay. Having been freed, Nelson Mandela visited Brazil in 1991. Enthusiastically received in Rio de Janeiro and in Salvador, where Afro-Brazilians formed the majority of the population, Mandela confirmed his intention to be a candidate to the presidency of South Africa, a position he was elected to in 1994, winding up the apartheid regime. A mood of optimism and confidence was established between the democratically elected governments. The return to their countries of South America's refugees and political emigres, some of whom shared studies or political activism in Allende's Chile, Mexico City, Havana, Geneva or Paris, facilitated contacts between intellectuals and leaders of Brazil and the Southern Cone.

During an official visit to Buenos Aires in 1987, President José Sarney was invited by his host, President Raúl Alfonsín, to visit Argentine uranium enrichment facilities. In the following year, Sarney retributed in an identical manner, bringing the Argentine president on a visit to a Brazilian uranium plant. Bilateral discussion led the two countries to adhere in 1994 to the Tlatelolco Treaty, which prohibited the nuclear weapons in Latin America. Subsequently, Buenos Aires and Brasília ratified the Treaty for the Non-Proliferation of Nuclear Weapons. The military and diplomatic understanding between the two countries consolidated the advances of Mercosur.

In parallel, Brazilian diplomacy, supported by Argentina, took the initiative in creating the South Atlantic Zone of Peace and Cooperation (ZOPACAS), endorsed by the UN in 1986 and completed by a declaration of the denuclearization of the South Atlantic, signed in Brasília in 1994. In addition to Argentina, Brazil, and Uruguay, 21 countries from the African Atlantic coast, from Cape Verde to South Africa, adhered to ZOPACAS. In 2003, a broader diplomatic initiative occurred with the creation of a Forum of Dialogue between South Africa, Brazil, and India (IBSA), defined as a coordination mechanism of "three large democracies and major economies from three different continents... developing, pluralistic, multicultural, multi-ethnic, multilingual and multi-religious nations."¹⁵

Formed in 2006, the BRIC group (Brazil, China, and India) became BRICS in 2010 with the adhesion of South Africa, bringing together the South African and Brazilian leaders in this forum of large emerging countries. Despite the treaties and the regional meetings, the discovery of large reserves of hydrocarbons in the South Atlantic led to the emergence of new geopolitical challenges. In 2018, Angola became the second most important oil producer in Africa, after Nigeria. Promising drills is also underway on the coast of Namibia and South Africa. On the other side of the ocean, large hydrocarbon reserves were discovered in the Pre-Salt layer along the Brazilian coast, as well as oil and shale gas reserves in mineral beds in Vaca Muerta, in Center-Western Argentina. There are also important undersea oil proven reserves detected around the Malvinas archipelago.

In this context, the United States government recreated and reintroduced the Forth Fleet in the South Atlantic. Established in the Second World War, the Fourth Fleet operated in the Caribbean and the Atlantic and Pacific Oceans surrounding Central and South America. In 1947 it was dissolved, and its vessels incorporated to other US Navy fleets across the world. Surprising its South Atlantic allies, George W. Bush's administration decided to reestablish it in 2008. Vivid reactions occurred in Argentina and Brazil, where President Cristina Kirchner and President Lula manifested their dissatisfaction. Lula was the most incisive, denouncing the fact that the Fourth Fleet would operate in the maritime zones of the Pre-Salt reserves that Brazil had just discovered. In addition, drilling by British companies near the Malvinas revived tensions between Buenos Aires and London, leading the other Mercosur countries to confirm their solidarity with Argentina. Another diplomatic disagreement opposed Brazil to the United States, following Edward Snowden's revelations about the Five Eyes Intelligence Alliance spying program. Learning that her personal messages had been tapped, President Dilma Rousseff, cancelled in October 2013 an official visit to Washington settled at the invitation of President Obama. Then, the American and British press drew attention to the fact that American espionage in the region focused on the Internet's undersea fiber optic cables along the Brazilian coast. Amongst them there are the four cables connecting sub-saharan Africa and part of the Indian Ocean to the Americas, which converge near Natal and Fortaleza, on the northeastern coast of Brazil.

After the accession of Mauricio Macri to the presidency of Argentina and Jair Bolsonaro to the presidency of Brazil, the two countries turned their backs on the policy of opening towards Africa, aligning with US diplomacy instead. Such change is evident in Brazil, where the Bolsonaro realignment with Washington diverge with multipolar policies under the presidencies of Lula and Dilma Rousseff, when the number of Brazil embassies in Africa (37) surpassed those in Latin America (32).

However, beyond presidential elections and political changes, long term trends inevitably bring the South Atlantic cultures closer. Even though it has not been yet ratified by parliaments and national congresses, the agreement between the European Union and Mercosur, negotiated for 20 years, was signed in June 2019, giving a new dynamic to the integration of South Atlantic countries and Paraguay. In the cultural sphere, the teaching of Portuguese has become obligatory in Argentine and Uruguayan schools. In Brazil the situation has been more uncertain following Dilma Rousseff's impeachment and the implementation of a secondary school teaching reform. Yet, school administrators and parents, especially those in the Brazilian southern frontier cities, want the teaching of Spanish to be made mandatory again. The new educational reform also suppressed the teaching of Afro-Brazilian and African history and culture, which had been made mandatory by a 2003 law.

Such setbacks did not overcome deeper movements that are giving a new dimension to the South Atlantic in the 21st century. First, there is the contrasting demography picture of this part of the world. While the fertility rate has remained more or less stable at around 2.25 births per year in Argentina, it has fallen regularly in Brazil, reaching 1.7 in 2018. Moreover, the composition of Brazilian society has changed considerably. As demonstrated by the 2010 national census, 52% of Brazil's population self-identified as Afro-descendants. The percentage increased further in the last years, making Afro-Brazilians the largest afro-descendant population outside Africa. In the same time, the Portuguese speaking African countries experience a strong demographic growth. According to the 2015 UN's global census projections, by the end of the 21st century the number of Portuguese speakers in Africa will outnumber the total population of Brazil and Portugal. Direct flights between Brazil and Angola and, to a lesser extent Mozambique, already transport small traders, businesspeople, and Brazilian evangelical missionaries to Luanda and Maputo. The success of Brazilian soap operas is patent in the Portuguese speaking African countries, while the tide of Brazilian neo-evangelical churches, specially the Igreja Universal do Reino de Deus, has gone beyond the frontiers of these countries and has seen important growth in South Africa. In opposite direction, the Angolans sacoleiros, salesman and, more often saleswomen, travel monthly from Luanda to São Paulo and back again, to buy Brazilian goods, generally clothes, in downtown popular shopping streets, bringing it back to be sold into Angolan shops and markets. By and large, there are already the signs of an African migratory current towards Brazil and the Southern Cone. The 21st century will be marked by a new convergence between the two slopes of the South Atlantic.