Paper: North Atlantic has Cooled over last Millenium

The paper Absolute chronologies from the ocean: Records from the longest-lived, non-colonial animals on Earth by Wanamaker et al studies a very long-lived clam (up to 3-4 centuries) common in the temperate to sub-polar North Atlantic Ocean. High resolution sections are taken from the shells to produce a sclerochronology using an oxygen isotope indicative of sea surface temperatures, as shown in red in the first graph below. The paper finds a cooling trend in the North Atlantic of approximately 2°C over the past milleneum:

figure from page 5

In addition, the reconstructed and measured sea surface temperatures in the 1940's and 1950's are found to be higher than the present. This paper may provide useful historical context for the recent, highly controversial paper on modern sea surface temperatures. 


Update: Another study in the same issue of PAGES news  (p. 37) of the North Atlantic sea surface temperatures using ocean sediments also shows temperatures to be higher in the 1940's and 1950's than the present and in the 1400-1500's than the present: