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2026
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| Online Access: | https://doi.org/10.5281/zenodo.19370002 |
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| author | Medina, Alvaro |
| author_facet | Medina, Alvaro |
| contents | <p><em>The Quaternary glacial-interglacial oscillation has persisted for approximately 2.6 million years, driven</em></p> <p><em>primarily by orbital forcing (Milankovitch cycles). Every previous interglacial period has terminated with a</em></p> <p><em>return to glacial conditions. The current interglacial — the Holocene (~11,700 BP to present) — has not</em></p> <p><em>followed this pattern. While elevated anthropogenic CO</em><span><em>2</em></span><em> is widely cited as the proximate cause of delayed</em></p> <p><em>glacial return, this explanation does not address why the Holocene climate system appears to have entered a</em></p> <p><em>qualitatively different stable state prior to significant anthropogenic influence. Here we propose that the</em></p> <p><em>anomalous stability of the Holocene results from a rate-dependent threshold crossing in Antarctic</em></p> <p><em>Circumpolar Current (ACC) strength, driven by the uniquely pulsed nature of the last deglaciation. Unlike</em></p> <p><em>previous deglaciations, which proceeded gradually under orbital forcing, the last deglaciation featured at</em></p> <p><em>least two episodes of extraordinarily rapid ice sheet collapse — Meltwater Pulse 1A (~14,600 BP; 14–18 m</em></p> <p><em>sea level equivalent in ~340 years) and Meltwater Pulse 1B (~11,300 BP; 7–10 m in a comparably short</em></p> <p><em>period) — separated by the Younger Dryas cold reversal (~12,900–11,700 BP), during which the system</em></p> <p><em>attempted but failed to return to glacial conditions. We hypothesize that this pulsed delivery of meltwater</em></p> <p><em>drove the ACC past a critical transport threshold that gradual, orbital-paced melt never exceeds, locking</em></p> <p><em>Antarctica into a degree of thermal isolation not achieved in any previous interglacial. This hypothesis</em></p> <p><em>generates four specific, testable predictions using existing ocean drilling cores and climate models.</em></p> <p> </p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_19370002 |
| institution | Zenodo |
| language | |
| publishDate | 2026 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Rate-Dependent Threshold in Antarctic Circumpolar Current Strength: Did Pulsed Deglaciation Break the Quaternary Glacial-Interglacial Cycle? Medina, Alvaro Antarctic Circumpolar Current, deglaciation meltwater pulse Holocene glacial-interglacial cycles rate-dependent threshold <p><em>The Quaternary glacial-interglacial oscillation has persisted for approximately 2.6 million years, driven</em></p> <p><em>primarily by orbital forcing (Milankovitch cycles). Every previous interglacial period has terminated with a</em></p> <p><em>return to glacial conditions. The current interglacial — the Holocene (~11,700 BP to present) — has not</em></p> <p><em>followed this pattern. While elevated anthropogenic CO</em><span><em>2</em></span><em> is widely cited as the proximate cause of delayed</em></p> <p><em>glacial return, this explanation does not address why the Holocene climate system appears to have entered a</em></p> <p><em>qualitatively different stable state prior to significant anthropogenic influence. Here we propose that the</em></p> <p><em>anomalous stability of the Holocene results from a rate-dependent threshold crossing in Antarctic</em></p> <p><em>Circumpolar Current (ACC) strength, driven by the uniquely pulsed nature of the last deglaciation. Unlike</em></p> <p><em>previous deglaciations, which proceeded gradually under orbital forcing, the last deglaciation featured at</em></p> <p><em>least two episodes of extraordinarily rapid ice sheet collapse — Meltwater Pulse 1A (~14,600 BP; 14–18 m</em></p> <p><em>sea level equivalent in ~340 years) and Meltwater Pulse 1B (~11,300 BP; 7–10 m in a comparably short</em></p> <p><em>period) — separated by the Younger Dryas cold reversal (~12,900–11,700 BP), during which the system</em></p> <p><em>attempted but failed to return to glacial conditions. We hypothesize that this pulsed delivery of meltwater</em></p> <p><em>drove the ACC past a critical transport threshold that gradual, orbital-paced melt never exceeds, locking</em></p> <p><em>Antarctica into a degree of thermal isolation not achieved in any previous interglacial. This hypothesis</em></p> <p><em>generates four specific, testable predictions using existing ocean drilling cores and climate models.</em></p> <p> </p> |
| title | Rate-Dependent Threshold in Antarctic Circumpolar Current Strength: Did Pulsed Deglaciation Break the Quaternary Glacial-Interglacial Cycle? |
| topic | Antarctic Circumpolar Current, deglaciation meltwater pulse Holocene glacial-interglacial cycles rate-dependent threshold |
| url | https://doi.org/10.5281/zenodo.19370002 |