Rapid 20th century warming reverses 900-year cooling in the Gulf of Maine

The Gulf of Maine has undergone recent, rapid ocean warming but the lack of long-term instrumental records limits context for these changes. The authors present multiple 300-year geochemical records (oxygen, nitrogen, and radiocarbon isotopes) measured in absolutely dated Arctica islandica shells from the western Gulf of Maine, combined with climate model simulations. Results suggest a long-term cooling over most of the last 1000 years, primarily driven by volcanic forcing and North Atlantic ocean dynamics. This trend was reversed by warming beginning in the late 1800s, likely due to increased atmospheric greenhouse gas concentrations and changes in western North Atlantic circulation. Climate model simulations indicate that warming over the last century was more rapid than almost any other 100-year period in the last 1000 years in the region.

Nina M. Whitney, Alan D. Wanamaker, Caroline C. Ummenhofer, Beverly J. Johnson, Nathaniel Cresswell-Clay, Karl J. Kreutz