Eemian Interglacial: Lessons from a Warmer, Resilient Past

By Lewis Loflin | Published May 9, 2025

The Eemian Interglacial (130,000–115,000 years ago) was 1–2°C warmer than today’s pre-industrial average, with 6–9m higher sea levels. Far from catastrophic, it supported thriving ecosystems and early humans, offering lessons for modern climate concerns. Geological evidence shows Earth’s resilience, countering alarmist narratives with natural variability and adaptation.

Eemian Climate

Global temperatures averaged 1–2°C above the pre-industrial ~14°C, driven by orbital changes increasing Northern Hemisphere solar radiation. Arctic temperatures rose 3–5°C above today’s -15°C to -20°C, melting 25% of Greenland’s ice and parts of Antarctica, raising sea levels 6–9m over millennia [Dutton et al., 2016]. Summers were ice-free (1–2M km² sea ice), triggering ice-albedo feedback, yet no runaway warming occurred, per sediment cores [Otto-Bliesner et al., 2019].

Ecosystem and Human Resilience

Forests reached the Arctic Circle, with hippos in the Thames and crocodiles in Arctic waters, per pollen and fossils [Overpeck et al., 2006]. Ice-free summers boosted phytoplankton, supporting fish and whales (diatom fossils) [CAPE, 2006]. Polar bears adapted, foraging terrestrially like brown bears, per a ~130,000-year-old Svalbard fossil and genetic continuity [Ingólfsson & Wiig, 2009]; [Hailer et al., 2012]. Neanderthals and early Homo sapiens (20–50-person bands) used Mousterian tools at sites like Krapina, Croatia (~130,000 years ago), and Qafzeh, Israel (~120,000 years ago), with burials and art showing social cohesion [Green et al., 2010]. They migrated as seas rose, exploiting coastal resources (e.g., Vanguard Cave, Gibraltar).

Natural Variability and Feedbacks

Eemian warming, driven by orbital forcing with CO2 at 280–300 ppm, was moderated by negative feedbacks. Evaporation (7% more vapor/°C) strengthened monsoons, creating a Sahara savanna with crocodiles. Cloud formation and heat redistribution prevented runaway effects, similar to the HCO, showing Earth’s self-regulation [Lambeck et al., 2020].

Aspect	Eemian Impact
Climate	1–2°C global, 3–5°C Arctic warming; 6–9m sea level rise
Ecosystems	Arctic forests, thriving marine life, polar bear adaptation
Humans	Neanderthal/Homo sapiens migration, coastal resource use

Modern Lessons

The Eemian’s 1–2°C warmth and 6–9m sea level rise, over millennia, saw no collapse. Today’s 1.1°C warming and faster rate (0.2°C/decade) pose challenges, but Eemian resilience suggests adaptation over fear. Early humans and polar bears thrived by leveraging natural systems, a model for today. For more paleoclimate insights, see my pole shift debunk or Holocene Climate Optimum on BristolBlog.com.

References

Dutton, A., et al. (2016). “Sea-Level Rise Due to Polar Ice-Sheet Mass Loss.” Science, 349(6244), aaa4019. [Link]
Overpeck, J. T., et al. (2006). “Paleoclimatic Evidence for Future Ice-Sheet Instability.” Science, 311(5768), 1747–1750. [Link]
Otto-Bliesner, B. L., et al. (2019). “Amplified Arctic Warming During the Last Interglacial.” Nature Communications, 10, 2256. [Link]
CAPE Last Interglacial Project Members (2006). “Last Interglacial Arctic Warmth.” Quaternary Science Reviews, 25(13-14), 1383–1400. [Link]
Lambeck, K., et al. (2020). “Sea Level and Global Ice Volumes.” Nature, 583, 90–95. [Link]
Green, R. E., et al. (2010). “A Draft Sequence of the Neandertal Genome.” Science, 328(5979), 710–722. [Link]
Hailer, F., et al. (2012). “Nuclear Genomic Sequences Reveal Polar Bear Lineage.” Science, 336(6079), 344–347. [Link]
Ingólfsson, Ó., & Wiig, Ø. (2009). “Late Pleistocene Fossil Find in Svalbard.” Polar Research, 28(3), 455–462. [Link]
Liu, S., et al. (2016). “Genomic Evidence for Polar Bear Evolution.” Molecular Biology and Evolution, 33(6), 1456–1467. [Link]
Welch, A. J., et al. (2014). “Polar Bear Genomic Adaptation.” Cell, 157(4), 785–794. [Link]

Acknowledgment: Thanks to Grok, created by xAI, for drafting assistance. Final edits and views are mine.