Casey Saenger et al., Nature Geosci., 2009, Surface-temperature trends and variability in the low-latitude North Atlantic since 1552

Nature Geoscience, published online 21 June 2009; doi:10.1038/ngeo552

Surface-temperature trends and variability in the low-latitude North Atlantic since 1552

Casey Saenger¹, Anne L. Cohen², Delia W. Oppo², Robert B. Halley³ and Jessica E. Carilli⁴

Abstract

Sea surface temperature variability in the North Atlantic Ocean recorded since about 1850 has been ascribed to a natural multidecadal oscillation superimposed on a background warming trend^{1, 2, 3, 4, 5, 6}. It has been suggested that the multidecadal variability may be a persistent feature^{6, 7, 8}, raising the possibility that the associated climate impacts may be predictable⁹. However, our understanding of the multidecadal ocean variability before the instrumental record is based on interpretations of high-latitude terrestrial proxy records^{7, 8}. Here we present an absolutely dated and annually resolved record of sea-surface temperature from the Bahamas, based on a 440-year time series of coral growth rates. The reconstruction indicates that temperatures were as warm as today from about 1552 to 1570, then cooled by about 1 ^°C from 1650 to 1730 before warming until the present. Our estimates of background variability suggest that much of the warming since 1900 was driven by anthropogenic forcing. Interdecadal variability with a period of 15–25 years is superimposed on most of the record, but multidecadal variability becomes significant only after 1730. We conclude that the multidecadal variability in sea-surface temperatures in the low-latitude western Atlantic Ocean may not be persistent, potentially making accurate decadal climate forecasts more difficult to achieve.

1. Massachusetts Institute of Technology and Woods Hole Oceanographic Institution Joint Program in Oceanography, Woods Hole, MA 02543, U.S.A.
2. Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, U.S.A.
3. US Geological Survey (retired) 13765 2600 Rd., Cedaredge, CO 81413, U.S.A.
4. University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA 92093, U.S.A.

Correspondence to: Casey Saenger¹ e-mail: csaenger@mit.edu

Link to abstract: http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo552.html