What Will 30 Trillion Tons of Waste Look Like in 100 Million Years?

Waste is not just what societies discard. It is one of the clearest records of who we are, how we live, and what kind of planet we are leaving behind. In this wide-ranging conversation, anthropologist Joshua Reno and geologist Jan Zalasiewicz explore waste as both a human problem and a geological force, moving from landfills and urban rubble to deep time, the Anthropocene, and the far future of Earth itself.  Joshua Reno, professor of anthropology at Binghamton University, studies the hidden systems societies depend on but prefer not to think about, especially landfills, disposal, and the cultural meanings of waste. Jan Zalasiewicz, geologist and paleontologist, has spent decades mapping the physical traces humans leave behind, from landfill strata and made ground to the broader geological signatures of the Anthropocene. Together, they bring two very different disciplines into unusually close conversation. They discuss why waste is both necessary and disavowed, how landfills reveal uncomfortable truths about human behavior, and why the geological scale of human leftovers is far larger than most people realize. They explore how cities preserve layers of industrial history like buried archives, why “waste as resource” is both useful and misleading, and how the accelerating production of waste changes our sense of time. From there, the conversation opens outward into questions of continuity, extinction, future readers, nuclear warning systems, the Fermi paradox, deep-time oceans, and what it means to leave a material record in a universe that may not care whether anyone is left to interpret it.   This conversation bridges anthropology, geology, environmental thought, philosophy, and deep time, revealing waste not as a side effect of civilization, but as one of its defining signatures.⸻TIMESTAMPS00:00:27 – Joshua Reno on landfills, hidden systems, and the paradox of necessary waste00:06:27 – Why studying trash reveals more than self-reporting ever can00:10:06 – Why many geologists resist treating landfill and waste as geology00:13:22 – The shocking scale of the technosphere and humanity’s waste legacy00:19:03 – Why pollution narratives are powerful but incomplete00:20:55 – Fly ash, landfill mining, and the complicated idea of “good waste”00:25:43 – Cities as layered archives: London, war, rubble, and urban strata00:29:23 – What landfill work feels like from the inside: constant motion, danger, and routine00:35:34 – Sewer epidemiology and why institutions often resist what waste can reveal00:39:00 – Future readers, lost continuity, and who might one day interpret our remains00:49:08 – Nihilism, speculative philosophy, and the spread of “the world after us” thinking00:53:12 – The Fermi paradox and whether civilizations accelerate into self-destruction01:00:35 – Nuclear waste, deep burial, and the problem of warning distant futures    ⸻GUESTSJoshua Reno – Professor of Anthropology, Binghamton UniversityAuthor of Waste Away: Working and Living with a North American Landfill and Military Waste: The Unexpected Consequences of Permanent War Readiness. His work examines waste, disposal, landfills, and the hidden systems that shape social life.Jan Zalasiewicz – Geologist, Paleontologist, and StratigrapherEmeritus Professor of Palaeobiology, University of Leicester, Author of The Earth After Us and co-author of The Cosmic Oasis. His work spans geology, paleobiology, the Anthropocene, and the long-term material traces of human civilization.