Does the El Niño–Southern Oscillation control the interhemispheric radiocarbon offset?
Abstract Since the 1970s it has been recognised that Southern Hemisphere samples have a lower radiocarbon content than contemporaneous material in the Northern Hemisphere. This interhemispheric radiocarbon offset has traditionally been considered to be the result of a greater surface area in the sou...
| Published in: | Quaternary Research |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2007
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1016/j.yqres.2006.08.008 http://api.elsevier.com/content/article/PII:S0033589406001104?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589406001104?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400004841 |
| Summary: | Abstract Since the 1970s it has been recognised that Southern Hemisphere samples have a lower radiocarbon content than contemporaneous material in the Northern Hemisphere. This interhemispheric radiocarbon offset has traditionally been considered to be the result of a greater surface area in the southern ocean and high-latitude deepwater formation. This is despite the fact that the El Niño–Southern Oscillation (ENSO) is known to play a significant role in controlling the interannual variability of atmospheric carbon dioxide by changing the flux of ‘old’ CO 2 from the tropical Pacific. Here we demonstrate that over the past millennium, the Southern Hemisphere radiocarbon offset is characterised by a pervasive 80-yr cycle with a step shift in mean values coinciding with the transition from the Medieval Warm Period to the Little Ice Age. The observed changes suggest an ENSO-like role in influencing the interhemispheric radiocarbon difference, most probably modulated by the Interdecadal Pacific Oscillation, and supports a tropical role in forcing centennial-scale global climate change. |
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