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Natural drivers of multidecadal Arctic sea ice variability over the last millennium


Halloran, PR and Hall, IR and Menary, M and Reynolds, DJ and Scourse, JD and Screen, JA and Bozzo, A and Dunstone, N and Phipps, S and Schurer, AP and Sueyoshi, T and Zhou, T and Garry, F, Natural drivers of multidecadal Arctic sea ice variability over the last millennium, Scientific Reports, 10, (1) Article 688. ISSN 2045-2322 (2020) [Refereed Article]


Copyright Statement

Copyright 2020 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1038/s41598-020-57472-2


The climate varies due to human activity, natural climate cycles, and natural events external to the climate system. Understanding the different roles played by these drivers of variability is fundamental to predicting near-term climate change and changing extremes, and to attributing observed change to anthropogenic or natural factors. Natural drivers such as large explosive volcanic eruptions or multidecadal cycles in ocean circulation occur infrequently and are therefore poorly represented within the observational record. Here we turn to the first high-latitude annually-resolved and absolutely dated marine record spanning the last millennium, and the Paleoclimate Modelling Intercomparison Project (PMIP) Phase 3 Last Millennium climate model ensemble spanning the same time period, to examine the influence of natural climate drivers on Arctic sea ice. We show that bivalve oxygen isotope data are recording multidecadal Arctic sea ice variability and through the climate model ensemble demonstrate that external natural drivers explain up to third of this variability. Natural external forcing causes changes in sea-ice mediated export of freshwater into areas of active deep convection, affecting the strength of the Atlantic Meridional Overturning Circulation (AMOC) and thereby northward heat transport to the Arctic. This in turn leads to sustained anomalies in sea ice extent. The models capture these positive feedbacks, giving us improved confidence in their ability to simulate future sea ice in in a rapidly evolving Arctic.

Item Details

Item Type:Refereed Article
Keywords:Arctic, sea ice, last millennium, climate models, Atlantic Meridional Overturning Circulation
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Palaeoclimatology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Climate change models
UTAS Author:Phipps, S (Dr Steven Phipps)
ID Code:136991
Year Published:2020
Web of Science® Times Cited:11
Deposited By:Geography and Spatial Science
Deposited On:2020-01-24
Last Modified:2021-07-05
Downloads:10 View Download Statistics

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