Global mean sea level over the past 4.5 million years

2025/10/16 by Peter U. Clark, Jeremy D. Shakun, Yair Rosenthal +9 · 1 voice · 6 citations
Earth and Planetary Sciences · #Geology and Paleoclimatology Research #Geological formations and processes #earthquake and tectonic studies

paper · doi:10.1126/science.adv8389

Abstract

Changes in global mean sea level (GMSL) during the late Cenozoic remain uncertain. We use a reconstruction of changes in δ 18 O of seawater to reconstruct GMSL since 4.5 million years ago (Ma) that accounts for temperature-driven changes in the δ 18 O of global ice sheets. Between 4.5 and 3 Ma, sea level highstands remained up to 20 m above present whereas the first lowstands below present suggest onset of Northern Hemisphere glaciation at 4 Ma. Intensification of global glaciation occurred from 3 Ma to 2.5 Ma, culminating in lowstands similar to the Last Glacial Maximum lowstand at 21,000 years ago and that reoccurred throughout much of the Pleistocene. We attribute the middle Pleistocene transition in ice sheet variability (1.2 Ma to 0.62 Ma) to modulation of 41-thousand-year (kyr) obliquity forcing by an increase in ~100-kyr CO 2 variability.

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• Relatively warm deep-water formation persisted in the Last Glacial Maximum. [europepmc]

Discussions

• It definitely piqued my interest to see Clark et al's reconstruction of sea level for the past 4.5 million years, something I first heard about several years ago. However, upon reading it, I am very s [bsky, 49 points, 1 comments]

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