Last Interglacial
Generated by GPT-5-miniExpansion Funnel Raw 107 → Dedup 0 → NER 0 → Enqueued 0
| Last Interglacial | |
|---|---|
| Name | Last Interglacial |
| Other names | Eemian, Ipswichian |
| Time start | ~129 ka |
| Time end | ~116 ka |
| Chronology | Marine Isotope Stage 5e |
| Preceding | Last Glacial Period |
| Following | Last Glacial Maximum |
Last Interglacial The Last Interglacial was a warm interval during Marine Isotope Stage 5e centered around ~129–116 thousand years ago, notable in Paleoclimatology records from Antarctica and Greenland and in terrestrial archives from Europe, Africa, and the Americas. It is widely correlated with the Eemian of northern European stratigraphy, the Ipswichian of British Quaternary studies, and with marine and speleothem chronologies used by researchers associated with institutions such as the National Oceanic and Atmospheric Administration, the British Geological Survey, and the Max Planck Society.
Definition and Chronology
The interval is defined primarily by isotope stratigraphy within Marine Isotope Stage 5 and is often dated using Uranium–thorium dating, Radiocarbon dating boundaries when applicable, and orbital tuning tied to the Milankovitch cycles recorded in cores from the North Atlantic and Mediterranean Sea. Chronologies are reconciled across records from Vostok, EPICA Dome C, GRIP, and GISP2 ice cores, along with OSL ages from European loess and the chronology frameworks employed by the International Commission on Stratigraphy and the Quaternary Research Association.
Climate and Environmental Conditions
During the interval, high-latitude regions such as Svalbard, Greenland Ice Sheet, and parts of Scandinavia experienced temperatures resembling or exceeding Holocene mid-Holocene warmth, as inferred from pollen sequences at sites like Lateglacial European basins, benthic foraminifera assemblages in the North Sea, and biomarker analyses used by teams at Woods Hole Oceanographic Institution and Scripps Institution of Oceanography. Monsoon systems influencing West Africa, South Asia, and the East Asian summer monsoon showed enhanced precipitation signaled by speleothem records from Yucatan, Dongge Cave, and Hulu Cave, while midlatitude vegetation reconstructions from the Loess Plateau and Great Plains indicate shifts in biome distribution documented by researchers at Cambridge University and Harvard University.
Sea Level and Ice Sheets
Global sea level during this interval is reconstructed as several meters above present based on coral terrace elevations from Bermuda, Bahamas, Red Sea, and Tasmania, and from oxygen isotope stratigraphy in cores from the Mediterranean Sea and Cariaco Basin. Estimates relate to partial collapse or retreat of the West Antarctic Ice Sheet and reductions in the Greenland Ice Sheet interpreted in ice-sheet models used by groups at NASA Goddard, the Potsdam Institute for Climate Impact Research, and the University of Toronto. Geological evidence from the Sunda Shelf, Great Barrier Reef, and Seychelles supports transient highstands that inform discussions in the Intergovernmental Panel on Climate Change assessments.
Flora, Fauna, and Human Presence
Vegetation maps indicate northward shifts of boreal forests into areas of Britain, Belgium, and Germany, while temperate woodlands expanded across Iberia and Italy, inferred from pollen records curated by the Natural History Museum, London and the Smithsonian Institution. Faunal assemblages included ranges of Neanderthals in Europe and early modern human presence in North Africa, Levant, and parts of China, supported by archaeological sites associated with institutions like the Louvre, British Museum, and Institut de Paléontologie Humaine. Megafauna distributions, documented in faunal lists from sites in Siberia, Alaska, and South Africa, reflect community shifts analyzed by researchers at Max Planck Institute for Evolutionary Anthropology and the University of Cambridge.
Causes and Climate Forcing
Forcing mechanisms invoked include insolation anomalies from variations in Earth's orbital eccentricity, obliquity, and precession documented in the orbital solutions of Milankovitch theory and applied in transient simulations by modeling centers such as NCAR and Met Office Hadley Centre. Greenhouse gas concentrations reconstructed from EPICA Dome C and Byrd Station ice cores show elevated but not extreme carbon dioxide and methane levels, while feedbacks involving sea-ice extent, vegetation albedo, and ice-sheet dynamics are explored in coupled model experiments by groups at MPI-M and NOAA Geophysical Fluid Dynamics Laboratory.
Proxy Records and Dating Methods
Key proxies include stable isotopes from foraminifera in marine cores collected by expeditions of the Challenger lineage and modern coring programs, speleothem growth layers dated by U–Th methods from caves such as Hulu Cave and Soplao, pollen stratigraphy archived at the Natural History Museum, Paris, and cosmogenic nuclide exposure ages from moraines in Alps, Himalaya, and Andes published with contributions from ETH Zurich and University of Bern researchers. Chronostratigraphic integration utilizes tephrochronology tied to volcanic events like those preserved from Santorini and Yellowstone.
Impacts and Relevance to Future Climate
The interval serves as an analog for projected warming in assessments by the IPCC and in impact studies by the World Meteorological Organization and IUCN, informing sea-level commitment scenarios relevant to Bangladesh, Netherlands, and Kiribati. Insights into ice-sheet stability, ice–ocean interactions studied at Lamont–Doherty Earth Observatory and Alfred Wegener Institute, and vegetation–climate feedbacks provide context for risk assessments by UNFCCC planners and conservation strategies of organizations like WWF and Conservation International.