Introduction: farewell to the Holocene city

By far, the largest span of human history was lived by our ancestors as nomadic hunter-gatherers (Bettinger et al., 2015; Barnard, 2020), involving quite distinctive terms of relationship with Earth (Ingold, 1996). While Homo Sapiens appeared around 300,000 years ago, two major precursors to urban human civilization – sedentary agriculture and permanent human settlements – consolidated only 10,000 to 12,000 years ago. This corresponds with the emergence of the Holocene approximately 11,650 calendar years before the present (Walker et al., 2009), the geological epoch that is arguably now ending to give way to the Anthropocene (Zalasiewicz et al., 2019). Marking the end of the last glacial period, the Holocene was characterized by fairly stable and particularly benign conditions for human life. It corresponds with the fast growth of our species worldwide and it witnessed most of written history, the rise and fall of civilizations and the transition to modern urban living. The city, in all its diverse shapes and cultures, is the epitome of modern human presence on Earth. Urban settlements have been the nesting shapes of human life in the singularly benevolent Holocene. Until now. The Holocene also witnessed an unprecedented impact of human action on the Biosphere leading to the current anthropogenic existential threats to ecosystems. The proposed new epoch of the Anthropocene, as explained below, is marked by an environmental disruption of geological scale. The very dominance and expansion of the human species is now endangering its own survival. The uniquely benign conditions of the Holocene are giving way to more challenging conditions for the viability of human life. It is paradise lost. As we leave the Holocene and come to terms with the realities of the Anthropocene, we are bound to experience unprecedented challenges to our prospects of continuing to inhabit this planet. The city, as the embodiment of our accommodation into the Earth System and the resulting urban culture, has been made possible only by its unique environmental conditions. As unique in geological history as they are fragile: around two-thirds of the Earth’s history (first 10 bn. years) there was no life and once it appeared (4 bn. years