John Parmentola: “How could Sea Levels Fall by 400 Feet During an Ice Age?” | Tom Nelson Pod #400

John Parmentola discusses a puzzle of how sea levels fell ~400 feet during ice ages and argues global annual solar input is nearly constant, implying compensating regional heating when the Arctic cools. Using Antarctic ice-core temperature proxies and orbital mechanics, he introduces a new “countervailing obliquity precession effect” (COPE): a biannual insolation asymmetry that increases tropical-zone energy deposition while Arctic summer insolation and melt potential decline, affecting the hydrological cycle, moisture transport, albedo, and glacial descent. He estimates the evaporation energy need (~10^26 J) and says COPE energy over millennia exceeds this. He cites satellite/top-of-atmosphere energy-balance analysis (~1 W/m² net gain) and notes tests: second-half-year precipitation bias, possible Arctic moisture-transport bias, and CO2 outgassing seasonality. Links to his preprint and related work are mentioned.00:00 Sea Level Ice Age Mystery09:33 Warming Before Glaciation12:01 Evaporation Energy Math13:28 Solar Input Basics17:10 Why Insolation Stays Constant20:54 Milankovitch Parameters Explained26:45 Obliquity Heat Redistribution29:08 Seasonal Zone Matrix33:33 Arctic Insolation Then vs Now40:05 Milankovitch Hypothesis Summary40:56 Snow Ice Evidence42:15 Orbit Month Swap43:54 Hidden Insolation Split46:12 Seasonal Energy Gap48:48 Tropical Energy Build50:15 COPE Defined53:01 Satellite Signal Test56:24 Past Interglacial Match59:22 Summary And Wrap01:01:08 Q And A Tests01:05:51 Website And Preprint01:06:30 Economic Growth Detour01:11:21 Final Links Farewellhttps://johnparmentola.com/2019: The Great Mystery of Economic Growth”: https://youtu.be/sx-55BhuFksJohn Parmentola: Estimating the Holocene Warm Period Termination | Tom Nelson Pod #96: https://youtu.be/6c3yW6s0shQ=========Slides, summaries, references, and transcripts of my podcasts: https://tomn.substack.com/p/podcast-summariesMy Linktree: https://linktr.ee/tomanelson1