Scientific but lyrical volume explores how the histories of glaciers and humans are intertwined

Glacier: Nature and Culture

By Peter G. Knight. Reaktion Books, 224 pages, 2019. $24.95

From the limited perspective of our own brief lives, and our recent arrival as a species here on Earth, we tend to think of glaciers as eternal, even as they rapidly vanish across the globe. But in truth, as Peter G. Knight tells us on the first page of “Glacier: Nature and Culture,” they’ve only graced our planet for about 15% of the time it has existed.

Yet that 15% is crucial, because glaciers are intimately tied to the rise of human civilization. They supply many of the vast river systems that irrigate out crops and slake our thirst. They carved the valleys and landscapes where many of our cites rest. In their advances and retreats they churned the soils that are the basis of agriculture, which enabled us to become more than simple hunter gathers.

They’re also melting at an alarming rate. The glaciers feeding major rivers running through China, India, and Southeast Asia are all found in the Himalayas, where every year they diminish. When they’re gone, the Yangtze, Ganges, and Mekong rivers will run dry in hot seasons, when over a billion people need water the most. What will happen next remains to be seen. Refugees heading to the coast won’t be an option. Melting glaciers and ice sheets far from the tropics will raise sea levels to the point where major cities will have to be abandoned, and another billion people will be cast adrift.

Knight, a lecturer in geography at England’s Keele University, alerts readers to these impending disasters in the latter sections of this book, but it isn’t all so glum. As part of British publisher Reaktion Books’ ongoing Earth Series, he’s been tasked, as the title implies, with exploring both the scientific understanding of his topic, and the human response to it. And as he’s careful to point out, science is an aspect of human culture. So really it’s two parts of the same story, but seen differently.

On the science side, Knight summarizes how glaciers form and what they do over the course of their lifespans. Essentially rivers of ice, they move not just frozen water, but, similar to liquid rivers, they also take anything that falls in their paths. Which is why melting glaciers have rendered up crashed airplanes, wooly mammoths, and even prehistoric humans.

They also function as time machines. Glaciers form as snow falls and freezes. What fails to thaw over the following summer is covered by the next year’s snowfall, and successive sheets are formed. The snow turned to ice traps tiny particles of debris that fell with it, as well as the air that each snowflake contained. Every layer is thus a barometer of sorts for the year it was created, offering a snapshot of what climate conditions were like at the time. Pull an ice core out of the Antarctic ice sheet, count back 10,000 layers, and subject the one you arrive at to a battery of tests. You will discover the chemical composition of the atmosphere of the time. Which is why we know that carbon dioxide levels were far lower before the Industrial Revolution, or even the beginnings of agriculture. It’s also why we know that the while carbon dioxide and methane levels have fluctuated both naturally and wildly throughout the planet’s history, the surge we are presently seeing is frighteningly rapid.

Glaciology, Knight explains, is a relatively new field of science, dating only to the mid-19th century. And aesthetic appreciation of glaciers didn’t really set in until the Romantic era that was cresting at the same time. Scientists, artists, poets, and people on holiday all turned their attention to glaciers in tandem. It’s a love affair that persists to this day, but carries with it a growing sadness. For as Knight writes early in the book, “The tragedy of this cultural ice age is that the point at which we noticed glaciers was a point at which they were on the brink of collapse, and that their collapse may be due partly to our own actions.”

Of course, glaciers have played a tragic role for as long as they have been beneficial. Humans have pretty much always known that glaciers move, even before they began exploring them. Throughout history, settlements built at the mouths of glaciers or within their greater pathway have periodically been consumed by them. Glacial ice can advance quickly, but it leaves enough time for a village or city to be deserted. This is not an option, however, when natural retaining walls give out and ice suddenly avalanches, or lakes held back by glacial ice barriers break through and water surges down mountainsides. It occurred twice in living memory on Nevado Huascarán, a high peak in Peru. The first time was in 1962, when 4,000 lives were lost. Then it happened again in 1970, this time killing 20,000.

Though technically not alive, glaciers are very much active, and so they convey a sense of living timelessness. This makes their escalating loss even more poignant. As symbols of human-driven climate change, there’s a sense that our time itself is running out alongside glaciers. Hence Knight writes about adventure travel outfits that sell their customers the idea of seeing glaciers now. While we still can.

Knight covers vast swaths of territory with this book, from a careful examination of the development of glaciology, to thoughtful critiques of art and literature inspired by and focusing upon glaciers. He explores their role in ecology and economics. He dives deeply into the millions of years of natural history behind glaciers, and ponders their future. His text is accompanied by over 100 illustrations, including many from Alaska. And his writing is lyrical. Whether the reader has never visited a glacier or has devoted their life to exploring them, they will find new perspectives and appreciations for these behemoth rivers of ice in this book.

“In glaciers,” Knight writes, “we recognize nature’s fragility, complexity, majesty, ephemerality, vastness, beauty, terror: in glaciers we see the sublime.”