"Man is everywhere a disturbing agent", wrote George Perkins Marsh in 1853 upon his return from a diplomatic post in Constantinople. He and his wife Caroline, both voracious readers and eager to discover new parts of the world, had taken advantage of his posting to travel through Europe and the Middle East. Sailing down the Nile from Cairo to the ancient city of Thebes they encountered countless species of exotic birds and reptiles, but not nearly as many wild plants. Hugging the river on both sides, lush cotton, sugarcane and wheat fields stretched across the valley. Beyond, the shaven hills were crowned with tufts of burnt grass. The Marshes noted the constant rattling of irrigation system wheels carrying water to the land and saw a world marked by millennia of human agricultural activity: "Barren terraces shaped the countryside into a geometrical patchwork and every sod turned or tree felled had left indelible records on the ground" (from The Invention of Nature. The Adventures of Alexander von Humboldt, the Lost Hero of Science by Andrea Wulf).
Following eight months in Egypt, the Marshes crossed the Sinai desert to Jerusalem and Beirut. The journey confirmed George's impression that the "assiduous husbandry of hundreds of generations" had made of this land an "effete and worn out planet". He had read Humboldt's books which described the natural world as interwoven with society, politics and colonialism, and had finally made sense of these ideas.
These observations were made in the context of booming agricultural industrialisation, particularly in the United States. Back in Vermont, George Marsh began what would become his renowned book Man and Nature (1864), in which he detailed the path to environmental destruction following clear arguments underpinned with statistics. He wrote about overfishing, chemical pollution, deforestation and increasing meat consumption, concluding that a vegetarian diet was more environmentally responsible. Marsh condemned humanity's greed with such force that the writer and environmentalist Wallace Stegner later called the book "the rudest kick in the face" to America's optimism. It took several decades for the ideas in Man and Nature to resonate but they did so with great impact, inspiring a new generation of environmental activists and giving birth to the conservation movement.
Many of Marsh's conclusions were based on Humboldt's Political Essay on the Kingdom of New Spain. Printed in four volumes between 1808 and 1811, this detailed commentary covered conflicts of race, labour conditions, and the environmental consequences of Spanish colonial rule. Humboldt, like Marsh, was meticulous in collecting information and data: he included tables of imports and exports between colonies, agricultural and mining yields as well as demographic data and botanical observations. He described how cash crops and monocultures impoverished soils and exhausted the land. Indigo planted to satiate Europe's lust for colourful clothing replaced edible crops, leading local people to poverty and dependency. Humboldt denounced slavery and for the first time, linked the exploitation of nature and environmental destruction to colonialism. No subject escaped Humboldt's thirst for knowledge. Seeking adventure and following his tropical dreams, he had sailed to the New World in 1799, hoping to discover how "all forces of nature are interlaced and interwoven". He was to become one of the greatest scientists that ever lived, shaping our current understanding of nature as a web of life where all is interconnected and interdependent. Humboldt's ideas were radical at a time when mankind sought to order, classify and govern nature. This global view meant that however small and seemingly insignificant, every organism and its environment were essential for the system to thrive. His travels in the colonies revealed to him how humankind was unpicking and pulling at the threads of this giant web.
Above: Humboldt's Naturgemälde or "painting of nature" showing plant distribution according to climate zones and altitude, as well as temperature, atmospheric pressure and humidity on the Chimborazo (with comparisons to the other major mountains of the world). More than anything, it illustrates Humboldt's holistic vision of nature and simultaneous attention to the finest detail. It was published upon his return from South America as a three-foot by two-foot print, astounding in its visual and scientific quality.
Humboldt and his travel companion Aimé Bonpland at the foot of Mount Chimborazo, painting by Friedrich Georg Weitsch (1810)
Marsh was not the only amateur naturalist inspired by Humboldt's ground-breaking approach to nature and the sciences. "How intensely I desire to be a Humboldt" were the words of young John Muir as he left his home town of Indianapolis to find passage to South America. It was late summer of 1867 and eight years since Humboldt had died at the age of eighty-nine. A series of unfortunate events lead Muir to the Sierra Nevada mountain range in California, where he discovered an 'Eden from end to end" carpeted with wildflowers. He was awestruck by the giant sequoias, the waterfalls fed by melting snow and the harmony of nature when left untouched. Muir recorded his impressions of that first summer in Yosemite Valley in a book later published as My First Summer in the Sierra and returned every year, comparing, measuring, drawing and collecting specimens to understand the origins of this magical oasis. He was the first to realise that glaciers had carved these cliffs and sketched the process in a style similar to Humboldt's Naturgemälde, annotating the migration of arctic plants over thousands of years. He read Humboldt and Marsh, noticing the growing threats to his beloved Sierra and began to lobby for its protection through nature writing. He campaigned for the creation of a national park in Yosemite and co-founded the Sierra Club, to this day America's largest grassroots environmental organisation. In Andrea Wulf's words, "Humboldt had understood the threat to nature, Marsh had assembled the evidence into one convincing argument, but it was Muir who planted environmental concerns into the wider political arena and the public mind." As I discovered recently, their combined work and insight gave rise to environmentalism, environmental activism and the conservation movement, as well as nature writing as a literary genre.
Looking Down Yosemite Valley by Albert Bierstadt (1865)
