Subtropical North Atlantic temperatures 60,000 to 30,000 years ago

A reconstruction of sea surface temperature based on alkenone unsaturation ratios in sediments of the Bermuda Rise provides a detailed record of subtr opical climate from 60,000 to 30,000 years ago. Northern Sargasso Sea tempe ratures changed repeatedly by 2 degrees to 5 degrees C, covarying with high -latitude temperatures that were previously inferred from Greenland ice cor es. The largest temperature increases were comparable in magnitude to the f ull glacial-Holocene warming at the site. Abrupt cold reversals of 3 degree s to 5 degrees C, Lasting Less than 250 years, occurred during the onset of two such even ts (Greenland interstadials 8 and 12), suggesting that the l argest, most rapid warmings were especially unstable.