Twentieth century warming in deep waters of the Gulf of St. Lawrence: A unique feature of the last millennium
Article first published online: 14 SEP 2010
Copyright 2010 by the American Geophysical Union.
Geophysical Research Letters
Volume 37, Issue 17, September 2010
How to Cite
2010), Twentieth century warming in deep waters of the Gulf of St. Lawrence: A unique feature of the last millennium, Geophys. Res. Lett., 37, L17604, doi:10.1029/2010GL044771., , , and (
- Issue published online: 14 SEP 2010
- Article first published online: 14 SEP 2010
- Manuscript Accepted: 9 AUG 2010
- Manuscript Received: 19 JUL 2010
- St. Lawrence;
- oxygen isotope;
 The impact of human activities on Earth's climate is still subject to debate and the pattern of a sharp recent global temperature increase contrasting with much lesser variable temperatures during preceding centuries has often been challenged, partly due to the lack of unquestionable evidence. In this paper, oxygen isotope compositions of benthic foraminifer shells recovered from sediments of the Lower St. Lawrence Estuary and the Gulf are used to reconstruct temperature changes in a water mass originating from ∼400 m deep North Atlantic waters. The data demonstrate that the 1.7 ± 0.3°C warming measured during the last century corresponds to a δ18O shift of 0.4 ± 0.05‰, encompassing the temperature effect and related change in the isotopic composition of the corresponding water mass. In contrast, δ18O values remained nearly constant over the last millennium, except for a small positive shift which we attribute to the Little Ice Age. We conclude that the 20th century warming of the incoming intermediate North Atlantic water has had no equivalent during the last thousand years.