Abrupt changes in early Holocene tropical sea surface temperature derived from coral records

For many high-latitude regions of the globe, it is now clear that the transition to modern climate following the Last Glacial Maximum was punctuated by a number of rapid and substantial climate oscillations. In contrast, relatively little is known about how the tropics responded to the deglaciation, because few high resolution records are available from lower latitudes. Corals have recently been shown to provide an important source of tropical climate records because they can be easily and accurately dated, using either ¹⁴C or ²³⁰Th, and because past sea surface temperatures can be recovered from the Sr/Ca ratios in coral skeletons. Here we use this technique to derive several early Holocene sea surface temperature records from a coral drill core recovered from Espiritu Santo, Vanuatu in the tropical southwest Pacific Ocean. These records indicate that sea surface temperatures in this region were depressed by as much as 6.5°C below modern values at ~10,350 calendar years BP, but rose very abruptly during the following 1,500 years. This temperature increase lags the post-Younger Dryas increase observed in a coral record from the tropical Atlantic Ocean by about 3,000 years, an unexpected phase-shift that may ultimately shed light on the mechanisms of deglacial climate change.