Late Holocene sea level variability and Atlantic Meridional Overturning Circulation

• Published in: Paleoceanography 2014-08, Vol.29 (8), p.765-777
• Main Authors: Cronin, T. M., Farmer, J., Marzen, R. E., Thomas, E., Varekamp, J. C.
• Format: Article
• Language: English
• Subjects: Atlantic Meridional Overturning; Atlantic Multidecadal Oscillation; Climate change; Climate variability; Coastal zone; Gauges; Holocene; Ice ages; Marine; Ocean circulation; Paleoclimate science; Sea level; Sea level rise; Sea surface temperature; Tidal marshes; Wetlands
• ISSN: 0883-8305; 2572-4517; 1944-9186; 2572-4525
• DOI: 10.1002/2014PA002632

Pre‐twentieth century sea level (SL) variability remains poorly understood due to limits of tide gauge records, low temporal resolution of tidal marsh records, and regional anomalies caused by dynamic ocean processes, notably multidecadal changes in Atlantic Meridional Overturning Circulation (AMOC). We examined SL and AMOC variability along the eastern United States over the last 2000 years, using a SL curve constructed from proxy sea surface temperature (SST) records from Chesapeake Bay, and twentieth century SL‐sea surface temperature (SST) relations derived from tide gauges and instrumental SST. The SL curve shows multidecadal‐scale variability (20–30 years) during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA), as well as the twentieth century. During these SL oscillations, short‐term rates ranged from 2 to 4 mm yr−1, roughly similar to those of the last few decades. These oscillations likely represent internal modes of climate variability related to AMOC variability and originating at high latitudes, although the exact mechanisms remain unclear. Results imply that dynamic ocean changes, in addition to thermosteric, glacio‐eustatic, or glacio‐isostatic processes are an inherent part of SL variability in coastal regions, even during millennial‐scale climate oscillations such as the MCA and LIA and should be factored into efforts that use tide gauges and tidal marsh sediments to understand global sea level rise. Key Points Sea level oscillations are a persistent feature of late Holocene climateSea level variations reflect Atlantic Meridional Overturning CirculationDistinguishing causes of sea level patterns should consider ocean processes