By Lewis Loflin | Published May 9, 2025
After the Eemian Interglacial’s warmth (130,000–115,000 years ago), Earth cooled into the Last Glacial Maximum (LGM, 26,500–19,000 years ago), with temperatures 5–10°C below today’s average and sea levels ~400 feet lower. Arctic species like polar bears, Arctic foxes, and marine mammals adapted to these shifts and subsequent warming, showing resilience. Geological and genetic evidence counters fears of species collapse, highlighting life’s endurance through climate variability.
Post-Eemian, orbital changes reduced Northern Hemisphere solar radiation, cooling global temperatures 5–10°C below today’s ~14°C by the LGM, with Arctic winters at -30°C or lower. Ice sheets lowered sea levels by ~123m (403 feet), and Arctic sea ice reached 10–12M km² in summer, vs. Eemian’s 1–2M [Polyak et al., 2010]. Warming from ~14,000 years ago raised sea levels ~400 feet over 20,000 years, per sediment cores and coral terraces [Lambeck et al., 2020].
Polar bears developed high-fat diet and white fur adaptations during the LGM, per genetic studies, with fossils (~10,000 years ago) showing Holocene persistence [Welch et al., 2014]; [Liu et al., 2016]. Arctic foxes, with 40,000-year-old Siberian fossils, expanded south during the LGM, hunting tundra mammals, and recolonized the Arctic post-ice retreat [Dalén et al., 2017]. Walruses thrived in ice-covered Bering Sea waters, per LGM fossils [Jakobsson et al., 2014].
Polar bear DNA shows no LGM bottlenecks, indicating stable populations [Liu et al., 2016]. Arctic foxes’ genetic diversity reflects migration and adaptation [Dalén et al., 2017]. Post-LGM, phytoplankton blooms supported marine food webs, per Bering Sea cores, mirroring Eemian’s ice-free summers [Jakobsson et al., 2014]. This shows ecosystems’ adaptability to both cooling and warming.
| Species | LGM Adaptation | Evidence |
|---|---|---|
| Polar Bear | High-fat diet, white fur | Genetic studies, fossils |
| Arctic Fox | Range expansion, tundra hunting | Fossils, genetic diversity |
| Walrus | Ice-covered water thriving | Bering Sea fossils |
Arctic species survived Eemian warmth and LGM cold, adapting to 5–10°C swings and 400-foot sea level changes. Today’s 1.1°C warming raises concerns, but polar bears’ flexibility (e.g., “grolar” hybrids) and post-LGM ecosystem recovery suggest resilience. Focus on adaptation, not fear, aligns with Earth’s history. See my pole shift debunk or Eemian Interglacial on BristolBlog.com.
Acknowledgment: Thanks to Grok, created by xAI, for drafting assistance. Final edits and views are mine.