State of the Planet

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Hatchets, Ratchets & Pivots: Book Talk by Ruth DeFries

By Rachael Lubitz

cover photoAs Professor Ruth DeFries aptly stated in her opening remarks at yesterday’s book launch for The Big Ratchet, if you look at satellite pictures of the earth, you see the imprint of the human species everywhere. Humans have come to dominate the planet. But how did this come to be? This question, among others, is what DeFries addresses in her new book, The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis. How did humans acquire the capability to spread out over the entire earth and control other species?

On Tuesday, The Earth Institute held a book launch to celebrate the book’s release. The event, at the Italian Academy on Columbia University’s Morningside campus, was attended by more than 150 students and faculty from across Columbia, friends and family of DeFries, and members of the local community. DeFries gave the audience a brief peek into her book, sharing some of her insights into what it takes to maintain a society as complex as ours. The talk was followed by a reception where DeFries signed books, and guests informally continued discussions exploring the topics that inspired the book.

(You can watch the full talk on The Earth Institute’s video page. For a Q&A with DeFries on State of the Planet, look here.)

DeFries first discussed the unique ability that humans have to accumulate and pass on a wide range of knowledge. We adapt and learn from our mistakes, and through a process of trial and error, we have created the technology and advancements to enable the world to sustain an ever-growing population. She credits much of our ability to thrive to our food systems: Through ingenuity and technology, we have taken control over nature and demanded it feed us.

Thousands of years ago, humans transitioned from hunters and gatherers to settle on farms, enabling us to formulate complex societies but bringing along a new host of unexpected problems. With the growth of farm life came the spread of disease from livestock and a less varied diet compared to the hunter-gatherer lifestyle. Humans also then needed to find a means of fertilizing a large amount of crops. DeFries pointed to the ingenuity of ancient Chinese societies that figured out how to move human waste from big cities to the countryside to fertilize the crops needed to feed people in those cities. She compared this method to earth’s natural recycling process of returning nutrient-filled waste to nature. In all, this method was vital in avoiding a Malthusian catastrophe. Humans outwitted nature, increasing agricultural production to keep pace with a growing society.

ruth defries
Professor Ruth DeFries speaks at the Italian Academy.

DeFries then elaborated on what she called the “hatchets, ratchets and pivots” of society. Every time a problem (a hatchet) in food production arose, a pivot was developed as a solution. For example, when cities became too large to move all the human waste to the countryside, farmers discovered guano, bird droppings that could be found in large quantities. As guano began to diminish in supply, countries fought wars to keep hold of it. Yet again, society soon found a way to pivot, finding a new resource to help keep food production high. The answer this time was found in synthesized fertilizer: Nitrogen gas could be taken from the air and turned into nourishment for crops. This solution was revolutionary; civilizations no longer had to be tethered to organic fertilizer supplies, but could craft them from chemical sources. Yet as we had come to expect throughout her talk, this ratchet was ultimately followed by a hatchet. The production of synthesized fertilizer led to the need for pesticides like DDT, which were later found to be toxic. And so the cycle of hatchets, ratchets and pivots continues.

DeFries concluded that we, as a society, have manipulated nature to such an extent that we unavoidably continue to create new problems. But our ingenuity has provided numerous solutions and necessary pivots, such that she has high hope for the future. Twelve thousand years ago, we successfully made the transition from foragers to farmers, and the fact that we have avoided worldwide catastrophe thus far is a testament to human creativity. Society has developed through a pattern of hatchets, ratchets and pivots, and while we will inevitably come across new problems, we will also continue to develop the solutions that sustain our civilization.

Rachael Lubitz is an undergraduate pursuing a B.A. in psychology and sustainable development, and an intern in the Executive Director’s Office at The Earth Institute. 

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