Central Equatorial Pacific Warming and Freshening in the Twentieth Century: Insights From a Coral Ensemble Approach

Nicholas T. Hitt, Hussein R. Sayani, Alyssa R. Atwood, Pamela R. Grothe, Christopher Maupin, Gemma K. O’Connor, Rachel M. Walter, Daniel Gebregiorgis, Madeleine E. Hardt, Yanbin Lu, Hai Cheng, R. Lawrence Edwards, Kim M. Cobb

Research output: Contribution to journalLetterpeer-review

1 Scopus citations

Abstract

The tropical Pacific influences climate patterns across the globe, yet robust constraints on decadal to centennial-scale climate variations are difficult to extract from sparse instrumental observations in this region. Oxygen isotope (δ18O) records from long-lived corals enable the quantitative reconstruction of tropical Pacific climate variability and trends over the twentieth century and beyond, but such corals are exceedingly rare. Here, we use multiple short coral δ18O records to create a coral ‘ensemble’ reconstruction of twentieth century climate in the central tropical Pacific. Ten U/Th-dated fossil coral δ18O records from Kiritimati Island (2°N, 157°W) span 1891 CE to 2006 CE, with the younger samples enabling quantitative comparison to a large ensemble of modern coral records and instrumental sea surface temperature. A composite record constructed of modern and fossil Kiritimati coral δ18O records shows a shift toward warmer and fresher conditions from 1970 CE onward, consistent with previously published records in this region.

Original languageEnglish (US)
Article numbere2021GL094051
JournalGeophysical Research Letters
Volume49
Issue number1
DOIs
StatePublished - Jan 16 2022

Bibliographical note

Funding Information:
We wish to thank Jessica Conroy, Liz Wiggins, Diane Thompson, and Lauren Toth for aiding with sample collection during the 2012–2014 Kiritimati expeditions. We would also like to extend our gratitude to Mathieu Pythoud, Pu Zhang, and Akemi Berry for assistance with U-series dating. We acknowledge the Republic of Kiribati for granting us permits to collect samples and conduct research on Kiritimati Island (number 005/13), provided by the Environment and Conservation Division. We especially thank Tiito Teabi for his support and expertise in the field on numerous expeditions to Kiritimati from 2012 to 2017. This research was funded by National Science Foundation Award 1502832, 1658182, 1635068, 1836645 to Kim M. Cobb, and the Georgia Institute of Technology Rutt Bridges Undergraduate Research Award to Nicholas Hitt. Nicholas Hitt was supported by New Zealand Royal Society Marsden Grant NIWA1602.

Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.

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