The Invention of Nature

4

South America

WHEREVER HUMBOLDT AND Bonpland turned during those first weeks in Cumaná, something new caught their attention. The landscape held a spell over him, Humboldt said. The palm trees were ornamented with magnificent red blossoms, the birds and fish seemed to compete in their kaleidoscopic hues, and even the crayfish were sky blue and yellow. Pink flamingos stood one-legged at the shore and the palms’ fanned leaves mottled the white sand into a patchwork of shade and sun. There were butterflies, monkeys and so many plants to catalogue that, as Humboldt wrote to Wilhelm, ‘we run around like fools.’ Even the usually unruffled Bonpland said that he would go ‘mad if the wonders don’t stop soon’.

Having always prided himself on his systematic approach, Humboldt found it difficult to come up with a rational method of studying his surroundings. Their trunks filled so quickly that they had to order more reams of paper on which to press their plants, and sometimes they found so many specimens that they could hardly carry them back to their house. Unlike other naturalists, Humboldt was not interested in filling taxonomic gaps – he was collecting ideas rather than just natural history objects, he said. It was the ‘impression of the whole’, Humboldt wrote, that captivated his mind more than anything.

Humboldt compared everything he saw with what he had previously observed and learned in Europe. Whenever he picked up a plant, a rock or an insect, his mind raced back to what he had seen at home. The trees that grew in the plains around Cumaná, with their branches forming parasol-like canopies, reminded him of Italian pines. When seen from a distance, the sea of cacti created the same effect as the grasses in the marshes in the northern climates. Here was a valley that made him think of Derbyshire in England, or caverns similar to those in Franconia in Germany, and those in the Carpathian Mountains in eastern Europe. Everything seemed somehow connected – an idea that would come to shape his thinking about the natural world for the rest of his life.

Humboldt in South America (Illustration Credit 4.1)

Humboldt had never been happier and healthier. The heat suited him and the fevers and nervous afflictions from which he had suffered in Europe disappeared. He even put on some weight. During the day he and Bonpland collected, in the evening they sat together and wrote up their notes and at night they took astronomical observations. One such night they stood awed for hours as a meteor shower drew thousands of white tails across the sky. Humboldt’s letters home burst with excitement and brought this wondrous world into the elegant salons of Paris, Berlin and Rome. He wrote of huge spiders that ate hummingbirds and of thirty-foot snakes. Meanwhile he amazed the people of Cumaná with his instruments; his telescopes brought the moon close to them and his microscopes transformed the lice in their hair into monstrous beasts.

There was one aspect that dampened Humboldt’s joy: the slave market opposite their rented house, in Cumaná’s main square. Since the early sixteenth century the Spanish had imported slaves to their colonies in South America and continued to do so. Every morning young African men and women were put on sale. They were forced to rub themselves with coconut oil to make their skin shiny black. They were then paraded for prospective buyers, who jerked open the slaves’ mouths to examine their teeth like ‘horses in a market’. The sight made Humboldt a life-long abolitionist.

Then, on 4 November 1799, less than four months after their arrival in South America, Humboldt for the first time felt the danger that might threaten his life and his plans. It was a hot and humid day. At midday dark clouds rolled in and by 4 p.m. thunderclaps reverberated across the town. Suddenly the ground began to tremble, almost knocking Bonpland to the floor as he was leaning over a table to examine some plants, and violently rocking Humboldt in his hammock. People ran screaming through the streets as houses crumbled, but Humboldt remained calm and climbed out of his hammock to set up his instruments. Even with the earth shaking nothing would prevent him from conducting his observations. He timed the shocks, noted how the quake rippled from north to south and took electric measurements. Yet for all his outward composure, Humboldt experienced inner turmoil. As the ground moved beneath him, it destroyed the illusion of a whole life, he wrote. Water was the element of motion, not the earth. It was like being woken, suddenly and painfully, from a dream. Until that moment he had felt an unwavering faith in the stability of nature, but he had been deceived. Now ‘we mistrust for the first time a soil, on which we had so long placed our feet with confidence,’ he said, but he was still determined to continue his travels.

He had waited for years to see the world and knew that he was putting his life in danger, but he wanted to see more. Two weeks later and after an anxious wait to draw money with his Spanish credit note (when it failed, the governor gave Humboldt money from his private funds), they left Cumaná for Caracas. In mid-November Humboldt and Bonpland – together with an Indian servant called José de la Cruz – chartered a small open thirty-foot local trading boat to sail westwards. They packed their many instruments and trunks, which were already filled with more than 4,000 plant specimens as well as insects, notebooks and tables of measurements.

Situated 3,000 feet above sea level, Caracas was home to 40,000 people. Founded by the Spanish in 1567, it was now the capital of the Captaincy General of Venezuela. Ninety-five per cent of the city’s white population were criollos, or as Humboldt called them ‘Hispano-Americans’ – white colonists of Spanish descent but born in South America. Though a majority, these South American creoles had been excluded from the highest administrative and military positions for decades. The Spanish crown had sent Spaniards to control the colonies, many of whom were less educated than the creoles. The wealthy creole plantation owners found it infuriating to be ruled by merchants dispatched from a distant mother country. The Spanish authorities treated them, some creoles complained, ‘as if they were vile slaves’.

Caracas lay nestled in a high valley skirted by mountains, near the coast. Once again Humboldt rented a house as a base from which to launch shorter excursions. From here Humboldt and Bonpland set out to scale the double-domed Silla, a mountain so close that they could see it from their house but which, to Humboldt’s surprise, no one he met in Caracas had ever climbed. On another day they rode into the foothills where they found a spring of the clearest water tumbling down a wall of shimmering rock. Observing a group of girls there, fetching water, Humboldt was suddenly struck by a memory of home. That evening he wrote in his journal: ‘Memories of Werther, Göthe and the king’s daughters’ – a reference to The Sorrows of Young Werther, in which Goethe had described a similar scene. On other occasions it was the particular shape of a tree, or a mountain, that gave him an immediate sense of familiarity. One glimpse of the stars in the southern sky or of the shape of the cacti against the horizon, was proof of how far away he was from his homeland. But then, all it took was the sudden tinkle of a cow bell or the roaring of a bull, and he was back in the meadows of Tegel.

Humboldt – far right, between the trees – sketching Silla (Illustration Credit 4.2)

‘Nature every where speaks to man in a voice,’ Humboldt said, that is ‘familiar to his soul’. These sounds were like voices from beyond the ocean that transported him in an instant from one hemisphere to another. Like the tentative pencil lines in a sketch, his new understanding of nature based on scientific observations and feelings was beginning to emerge. Memories and emotional responses, Humboldt realized, would always form part of man’s experience and understanding of nature. Imagination was like ‘a balm of miraculous healing properties’, he said.

Soon it was time to move on – inspired by the stories Humboldt had heard about the mysterious Casiquiare River. More than half a century earlier a Jesuit priest had reported that the Casiquiare connected the two great river systems of South America: the Orinoco and the Amazon. The Orinoco forms a sweeping arc from its source in the south near today’s border between Venezuela and Brazil to its delta on the north-eastern coast of Venezuela where it discharges into the Atlantic Ocean. Almost 1,000 miles further south along the coast is the mouth of the mighty Amazon – the river that crosses almost the entire continent from its source in the west in the Peruvian Andes less than 100 miles from the Pacific coast to the Brazilian Atlantic coast in the east.

Deep in the rainforest, 1,000 miles to the south of Caracas, the Casiquiare reputedly linked the network of tributaries of these two great rivers. No one had been able to prove its existence and few believed that major rivers such as the Orinoco and the Amazon could in fact be connected. All the scientific understanding of the day suggested that the Orinoco and Amazon basins had to be separated by a watershed because the idea of a natural waterway linking two large rivers was against all empirical evidence. Geographers had not found a single instance where it occurred elsewhere on the globe. In fact, the most recent map of the region showed a mountain range – the suspected watershed – exactly in the location where Humboldt had heard rumours that the Casiquiare might be.

There was much to prepare. They had to choose instruments that were small enough to fit into the narrow canoes in which they would be travelling. They needed to organize money and goods to pay for guides and food even in the deepest jungle. Before they set off, though, Humboldt dispatched letters to Europe and North America, asking his correspondents to publish them in newspapers. He understood the importance of publicity. From La Coruña in Spain, for example, Humboldt had written forty-three letters just before their departure. If he died during the voyage, he would at least not be forgotten.

On 7 February 1800, Humboldt, Bonpland and José, their servant from Cumaná, departed from Caracas on four mules, leaving behind most of their luggage and collections. To reach the Orinoco, they would have to head south on an almost exactly straight line through the huge emptiness of the Llanos – vast plains the size of France. The plan was to go to the Rio Apure, a tributary of the Orinoco about 200 miles to the south of Caracas. There they would procure a boat and provisions for their expedition at San Fernando de Apure, a Capuchin mission. First, though, they would go west, on a 100-mile detour to see the lush valleys of Aragua, one of the wealthiest agricultural regions in the colonies.

With the rainy season over, it was hot and much of the land through which they rode was arid. They crossed mountains and valleys, and after seven exhausting days, they finally saw the ‘smiling valleys of Aragua’. Stretching west were endless neat rows of corn, sugarcane and indigo. In between they could see small groves of trees, little villages, farmhouses and gardens. The farms were connected by paths lined with flowering shrubs and the houses shaded by large trees – tall ceibas clothed in thick yellow blossoms with their branches plaited into the flamboyant orange blooms of coral trees.

In the midst of the valley and surrounded by mountains was Lake Valencia. About a dozen rocky islands dotted the lake, some large enough to pasture goats and to farm. At sunset thousands of herons, flamingos and wild ducks brought the sky alive as they flew across the lake to roost on the islands. It looked idyllic but, as the locals told Humboldt, the lake’s water levels were falling rapidly. Vast swathes of land that only two decades earlier had been under water were now densely cultivated fields. What had once been islands were now hillocks on dry land as the shoreline continued to recede. Lake Valencia also had a unique ecosystem: with no outflow to the ocean and only small brooks running in, its water levels were regulated by evaporation alone. The locals believed that an underground outlet drained the lake, but Humboldt had other ideas.

Lake Valencia in the Aragua Valley (Illustration Credit 4.3)

He measured, examined and questioned. When he found fine sands on the higher levels of the islands, he realized that they had once been submerged. He also compared the annual average evaporation of rivers and lakes across the world, from southern France to the West Indies. As he investigated, he concluded that the clearing of the surrounding forests, as well as the diversion of water for irrigation, had caused the falling water levels. As agriculture had flourished in the valley, planters had drained and diverted some of the brooks that fed into the lake to irrigate their fields. They had felled trees to clear land, and with it the forest’s undergrowth – moss, brushwood and root systems – had disappeared, leaving the soils beneath exposed to the elements and incapable of water retention. Just outside Cumaná, locals had already told him that the dryness of the land had increased in tandem with the clearing of ancient groves. And on the way from Caracas to the Aragua Valley, Humboldt had noted the dry soils and bemoaned that the first colonists had ‘imprudently destroyed the forest’. As the soils had become depleted and fields had yielded less, the planters had moved west along a path of destruction. ‘Forest very decimated,’ Humboldt scribbled in his diary.

Just a few decades previously, the mountains and foothills that surrounded the Aragua Valley and Lake Valencia had been forested. Now, with the trees felled, heavy rains had washed away the soil. All this was ‘closely connected’, Humboldt concluded, because in the past the forests had shielded the soil from the sun and thereby diminished the evaporation of the moisture.

It was here, at Lake Valencia, that Humboldt developed his idea of human-induced climate change. When he published his observations, he left no doubt what he thought:

When forests are destroyed, as they are everywhere in America by the European planters, with an imprudent precipitation, the springs are entirely dried up, or become less abundant. The beds of the rivers, remaining dry during a part of the year, are converted into torrents, whenever great rains fall on the heights. The sward and moss disappearing with the brush-wood from the sides of the mountains, the waters falling in rain are no longer impeded in their course: and instead of slowly augmenting the level of the rivers by progressive filtrations, they furrow during heavy showers the sides of the hills, bear down the loosened soil, and form those sudden inundations, that devastate the country.

A few years earlier, when working as a mining inspector, Humboldt had already noted the excessive clearing of forests for timber and fuel in the Fichtel Mountains near Bayreuth. His letters and reports from that time were peppered with suggestions on how to reduce the need for timber in mines and ironworks. He had not been the first to comment on this but previously the reasons for concern had been economical rather than environmental. Forests provided the fuel for manufacturing, and timber was not only an important building material for houses but also for ships which in turn were essential for empires and naval powers.

Timber was the oil of the seventeenth and eighteenth centuries, and any shortages created similar anxieties about fuel, manufacturing and transport, as threats to oil production do today. As early as 1664, the English gardener and writer John Evelyn had written a bestselling book on forestry – Sylva, a Discourse of Forest Trees – in which he addressed timber shortage as a national crisis. ‘We had better be without gold than without timber,’ Evelyn had declared, because without trees there would be no iron and glass industries, no blazing fires warming homes during cold winter nights, nor a navy to protect the shores of England.

Five years later, in 1669, the French Minister of Finance, Jean-Baptiste Colbert, had outlawed much of the communal right to use the forests in villages, and had planted trees for the navy’s future use. ‘France will perish for the want of wood,’ he had said on introducing his draconian measures. There had even been some lone voices in the vast lands of the North American colonies. In 1749 the American farmer and plant collector John Bartram had lamented that ‘timber will soon be very much destroyed’ – a concern echoed by his friend Benjamin Franklin who had also feared the ‘loss for wood’. As a solution Franklin had invented a fuel-efficient fireplace.

Now, at Lake Valencia, Humboldt began to understand deforestation in a wider context and projected his local analysis forward to warn that the agricultural techniques of his day could have devastating consequences. The action of humankind across the globe, he warned, could affect future generations. What he saw at Lake Valencia he would see again and again – from Lombardy in Italy to southern Peru, and many decades later in Russia. As Humboldt described how humankind was changing the climate, he unwittingly became the father of the environmental movement.

Humboldt was the first to explain the fundamental functions of the forest for the ecosystem and climate: the trees’ ability to store water and to enrich the atmosphere with moisture, their protection of the soil, and their cooling effect.¹ He also talked about the impact of trees on the climate through their release of oxygen. The effects of the human species’ intervention were already ‘incalculable’, Humboldt insisted, and could become catastrophic if they continued to disturb the world so ‘brutally’.

Humboldt would see again and again how humankind unsettled the balance of nature. Only a few weeks later, deep in the Orinoco rainforest, he would observe how some Spanish monks in a remote mission illuminated their ramshackle churches with oil harvested from turtle eggs. As a consequence, the local population of turtles had already been substantially reduced. Every year the turtles would lay their eggs along the river’s beach, but instead of leaving some eggs to hatch the next generation, the missionaries collected so many that with every passing year, as the natives told Humboldt, their numbers had shrunk. Earlier, at the Venezuelan coast, Humboldt had also noted how unchecked pearl fishing had completely depleted the oyster stocks. It was all an ecological chain reaction. ‘Everything,’ Humboldt later said, ‘is interaction and reciprocal.’

Humboldt was turning away from the human-centred perspective that had ruled humankind’s approach to nature for millennia: from Aristotle, who had written that ‘nature has made all things specifically for the sake of man’, to botanist Carl Linnaeus who had still echoed the same sentiment more than 2,000 years later, in 1749, when he insisted that ‘all things are made for the sake of man’. It had long been believed that God had given humans command over nature. After all, didn’t the Bible say that man should be fruitful and ‘replenish the earth, and subdue it: and have dominion over fish of the sea, and over fowl of the air, and over every living thing that moveth upon the earth’? In the seventeenth century the British philosopher Francis Bacon had declared, ‘the world is made for man,’ while René Descartes had argued that animals were effectively automata – complex, perhaps, but not capable of reason and therefore inferior to humans. Humans, Descartes had written, were ‘the lords and possessors of nature’.

In the eighteenth century ideas of the perfectibility of nature dominated western thinking. Humankind would make nature better through cultivation, it was believed, and ‘improvement’ was the mantra. Orderly fields, cleared forests and neat villages turned a savage wilderness into pleasing and productive landscapes. The primeval forest of the New World by contrast was a ‘howling wilderness’ that had to be conquered. Chaos had to be ordered, and evil had to be transformed into good. In 1748 the French thinker Montesquieu had written that humankind had ‘rendered the earth more proper for their abode’ – with their hands and tools making the earth habitable. Orchards loaded with fruits, tidy vegetable gardens and meadows grazed by cattle were the ideal of nature at the time. It was a model that would long rule the western world. Almost a century after Montesquieu’s assertion, the French historian Alexis de Tocqueville, during a visit to the United States in 1833, thought that it was ‘the idea of destruction’ – of man’s axe in the American wilderness – that gave the landscape its ‘touching loveliness’.

Some North American thinkers even argued that the climate had changed for the better since the first settlers arrived. With every tree that was cut from the virgin forest, they insisted, the air had become healthier and milder. Lack of evidence didn’t stop them from preaching their theories. One such was Hugh Williamson, a physician and politician from North Carolina, who published an article in 1770 that celebrated the clearing of huge swathes of forests, which, he claimed, was to the benefit of the climate. Others believed that clearing the forests would increase winds which in turn would carry healthier air across the land. Only six years before Humboldt’s visit to Lake Valencia, one American had proposed that felling trees in the interior of the continent would be a useful way of ‘drying up the marshes’ along the coast. The few voices of concern remained restricted to private letters and conversations. On the whole the ‘subduing of the wilderness’, most agreed, was the ‘foundation for future profit’.

The man who had probably done most to spread this view was the French naturalist Georges-Louis Leclerc, Comte de Buffon. During the mid-eighteenth century Buffon had painted a picture of the primeval forest as a horrendous place full of decaying trees, rotting leaves, parasitic plants, stagnant pools and venomous insects. The wilderness, he said, was deformed. Though Buffon had died the year before the French Revolution, his views of the New World still shaped public opinion. Beauty was equated with utility and every acre wrested from the wilderness was a victory of civilized man over uncivilized nature. It was ‘cultivated nature’, Buffon had written, that was ‘beautiful!’.

Humboldt, however, warned that humankind needed to understand how the forces of nature worked, how those different threads were all connected. Humans could not just change the natural world at their will and to their advantage. ‘Man can only act upon nature, and appropriate her forces to his use,’ Humboldt would later write, ‘by comprehending her laws.’ Humankind, he warned, had the power to destroy the environment and the consequences could be catastrophic.

¹ Humboldt later put it succinctly: ‘The wooded region acts in a threefold manner in diminishing the temperature; by cooling shade, by evaporation, and by radiation.’