Rapid sea-level rise in the Gulf of Maine, USA, since AD 1800

Abstract

Two sea-level records from salt marshes in coastal Maine are derived from foraminiferal analyses and AMS 14C, 210Pb, 137Cs and pollen chronology. Both records cover the period from AD 800 until the present and show corresponding patterns of sea-level change when corrected for trends which could accommodate millennial-scale isostatic adjustments. The records provide a detailed sea-level chronology for the last few centuries and thus link the instrumental (tide-gauge) record with the long-term geological record of sea-level change. Results show that sea level was relatively stable between AD 800 and 1300 and reached a lowstand around AD 1800, which was preceded by an oscillation in the eighteenth century. Since AD 1800, sea levels in the Gulf of Maine have risen by 0.3-0.4 m. The onset of this rise corresponds with regional climatic warming and could be interpreted as thermal expansion of the Gulf of Maine and North Atlantic sea surface. Sea-level rise possibly slowed temporarily during the mid-nineteenth century, but twentieth-century rates are unprecedented in the last millennium and correspond with hemispheric warming.