Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia

Sea-level reconstructions over the past two millennia provide a pre-industrial context to assess whether the magnitude and rate of modern sea-level change is unprecedented. Sea-level records from the Indian Ocean over the past 2,000 years are sparse, while records from the Atlantic and Pacific Ocean...

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Main Authors: Kench, Paul S., McLean, Roger F., Owen, Susan D., Ryan, Emma, Morgan, Kyle Meredith, Ke, Lin, Wang, Xianfeng, Roy, Keven
Other Authors: Asian School of the Environment
Format: Article
Language:English
Published: 2021
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Online Access:https://hdl.handle.net/10356/146658
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1466582021-03-06T20:11:21Z Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia Kench, Paul S. McLean, Roger F. Owen, Susan D. Ryan, Emma Morgan, Kyle Meredith Ke, Lin Wang, Xianfeng Roy, Keven Asian School of the Environment Earth Observatory of Singapore Engineering::Environmental engineering Ocean Sciences Palaeoceanography Sea-level reconstructions over the past two millennia provide a pre-industrial context to assess whether the magnitude and rate of modern sea-level change is unprecedented. Sea-level records from the Indian Ocean over the past 2,000 years are sparse, while records from the Atlantic and Pacific Oceans show variations less than 0.25 m and no significant negative excursions. Here, we present evidence of two low sea-level phases in the Maldives, Indian Ocean, based on fossil coral microatolls. Microatoll growth is constrained by low water levels and, consequently, they are robust recorders of past sea level. U–Th dating of the Maldivian corals identified lowstands at ad 234–605 and ad 1481–1807 when sea level fell to maximum depths of −0.88 m and −0.89 m respectively. These lowstands are synchronous with reductions in radiative forcing and sea surface temperature associated with the Late Antiquity Little Ice Age and the Little Ice Age. Our results provide high-fidelity observations of lower sea levels during these cool periods and show rates of change of up to 4.24 mm yr−1. Our data also confirm the acceleration of relative sea-level rise over the past two centuries and suggest that the current magnitude and rate of sea-level rise is not unprecedented. National Research Foundation (NRF) Accepted version We thank LaMer Group and the Small Island Research Centre, Fares-Maathodaa, Huvadhoo atoll for logistical support, Government of the Maldives for research permission and A. Vila-Concejo, E. Beetham and T. Turner for field assistance. X.W. acknowledges funding support from the National Research Foundation of Singapore (grant nos. NRF2017NRF-NSFC001-047 and NRF-NRFF2011-08) and the Earth Observatory of Singapore. 2021-03-04T06:12:49Z 2021-03-04T06:12:49Z 2019 Journal Article Kench, P. S., McLean, R. F., Owen, S. D., Ryan, E., Morgan, K. M., Ke, L., . . . Roy, K. (2020). Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia. Nature Geoscience, 13(1), 61-64. doi:10.1038/s41561-019-0503-7 1752-0894 https://hdl.handle.net/10356/146658 10.1038/s41561-019-0503-7 1 13 61 64 en NRF2017NRF-NSFC001-047 NRF-NRFF2011-08 Nature Geoscience © The Author(s), under exclusive licence to Springer Nature Limited. All rights reserved. This paper was published in Nature Geoscience and is made available with permission of The Author(s). application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Environmental engineering
Ocean Sciences
Palaeoceanography
spellingShingle Engineering::Environmental engineering
Ocean Sciences
Palaeoceanography
Kench, Paul S.
McLean, Roger F.
Owen, Susan D.
Ryan, Emma
Morgan, Kyle Meredith
Ke, Lin
Wang, Xianfeng
Roy, Keven
Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
description Sea-level reconstructions over the past two millennia provide a pre-industrial context to assess whether the magnitude and rate of modern sea-level change is unprecedented. Sea-level records from the Indian Ocean over the past 2,000 years are sparse, while records from the Atlantic and Pacific Oceans show variations less than 0.25 m and no significant negative excursions. Here, we present evidence of two low sea-level phases in the Maldives, Indian Ocean, based on fossil coral microatolls. Microatoll growth is constrained by low water levels and, consequently, they are robust recorders of past sea level. U–Th dating of the Maldivian corals identified lowstands at ad 234–605 and ad 1481–1807 when sea level fell to maximum depths of −0.88 m and −0.89 m respectively. These lowstands are synchronous with reductions in radiative forcing and sea surface temperature associated with the Late Antiquity Little Ice Age and the Little Ice Age. Our results provide high-fidelity observations of lower sea levels during these cool periods and show rates of change of up to 4.24 mm yr−1. Our data also confirm the acceleration of relative sea-level rise over the past two centuries and suggest that the current magnitude and rate of sea-level rise is not unprecedented.
author2 Asian School of the Environment
author_facet Asian School of the Environment
Kench, Paul S.
McLean, Roger F.
Owen, Susan D.
Ryan, Emma
Morgan, Kyle Meredith
Ke, Lin
Wang, Xianfeng
Roy, Keven
format Article
author Kench, Paul S.
McLean, Roger F.
Owen, Susan D.
Ryan, Emma
Morgan, Kyle Meredith
Ke, Lin
Wang, Xianfeng
Roy, Keven
author_sort Kench, Paul S.
title Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
title_short Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
title_full Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
title_fullStr Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
title_full_unstemmed Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
title_sort climate-forced sea-level lowstands in the indian ocean during the last two millennia
publishDate 2021
url https://hdl.handle.net/10356/146658
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