EGU21-16401, updated on 10 Jan 2024
https://doi.org/10.5194/egusphere-egu21-16401
EGU General Assembly 2021
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Bivalves indicate that the North Atlantic was under stress before the onset of the Little Ice Age

Beatriz Arellano Nava, Paul R. Halloran, Chris A. Boulton, and Timothy M. Lenton
Beatriz Arellano Nava et al.
  • College of Life and Environmental Sciences, University of Exeter

The last millennium was characterised by a cooling from the Medieval Warm Period into the Little Ice Age. While strong volcanic eruptions could have triggered the onset of the Little Ice Age by reducing solar irradiance, modelling experiments suggest that it was amplified and maintained by sea ice-ocean feedbacks, including a potential abrupt weakening of the subpolar gyre. The weakening of negative feedbacks that maintain a system in a stable state, prior to an abrupt transition, can be detected as an increase in temporal autocorrelation and variability. Here we use an annually-resolved and absolutely dated shell-derived record from the North Icelandic Shelf that spans the last millennium, to detect such a loss of resilience in the marine environment leading up to the Little Ice Age transition. We find a significant increase in autocorrelation and variance in bivalve growth increments and oxygen isotopes before the transition, providing evidence consistent with loss of stability in the marine environment. This supports the idea that internal feedbacks played an important role in the Little Ice Age onset.

How to cite: Arellano Nava, B., Halloran, P. R., Boulton, C. A., and Lenton, T. M.: Bivalves indicate that the North Atlantic was under stress before the onset of the Little Ice Age, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16401, https://doi.org/10.5194/egusphere-egu21-16401, 2021.

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