Desiccated agricultural fields in Iraq. Photo from Unsplash.

The following is an excerpt from Metabolic Rifts: Capitalism’s Assault on the Earth System by author and ecosocialist activist Ian Angus, released on March 23, 2026 by Monthly Review Press. For more information, visit www.monthlyreview.org.

Karl Marx famously wrote that we humans make our own history but not under conditions of our own choosing. He was referring to the limits that the recent past imposes on our thinking and ability to act, but his insight also describes the restrictions that the Earth System placed on our ancestors for hundreds of thousands of years.

The first modern humans evolved from earlier primates about 300,000 years ago. These homo sapiens were every bit as intellectually and physically capable as we are: place them in the 21st century and they could quickly learn to use smartphones and automobiles. But for 300,000 years, all of our ancestors lived in small groups of hunter gatherers until, beginning about 11,000 years ago, agriculture was invented in Mesopotamia and then independently invented in parts of China, Central America, India, Africa, North America, and South America.

The world’s first great cities—Çatalhöyük in Turkey; Eridu, Uruk, and Ur in Mesopotamia; Ain Ghazal in Jordan; Mehrgarh in Pakistan; Memphis in Egypt, and more—were built during the same period of rapid economic and social change.

Global climate played a critical role in this worldwide change from small nomadic groups to farming and the first great civilizations. A study of ice-core data by scientists at the Potsdam Institute for Climate Impact Research, shows the average annual temperature in Greenland over the past 100,000 years. The first 90 percent of that time was characterized by repeated glacial advances and retreats: the global climate was not only cold, it was in general extremely variable.

Climate historian William J. Burroughs, who calls that time the reign of chaos, argues compellingly that so long as rapid and chaotic climate change continued, agriculture and settled life were impossible. To succeed, agriculture needs not just warm seasons, but a stable and predictable climate—and indeed, not long after the chaos ended, humans on five continents independently took up farming as their permanent way of life. “Once the climate had settled down into a form that is in many ways recognizable today, all the trappings of our subsequent development (agriculture, cities, trade etc.) were able to flourish.”

The Holocene epoch, which began when the ice last retreated, has been one of the longest stable warm periods in the last half million years. From 11,700 years ago to the 20th century, the average global temperature didn’t vary by more than one degree Celsius—up or down half a degree. That is not to say that Holocene weather........

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