ABSTRACT:

Over the past 150 years, global temperatures have increased by 0.6°C. It has been suggested that this increase in temperature, especially since 1980, has been unprecedented over the past millennium. In order to put the current warming trend into context, various efforts are underway to reconstruct the longer pre-instrumental history of climate variability. Here, we present a sea surface temperature (SST) record of the Indo-Pacific Warm Pool (IPWP) for the Common Era by combining seven high-resolution records of Globigerinoides ruber Mg/Ca from different locations within the Indonesian Seas. The much broader spatial coverage and enhanced temporal resolution of this composite record allows us to assess whether the observed 20th century warming and the rate of 20th century temperature change within IPWP have been unprecedented in the past two millennia. Our results indicate that (1) there exists a few intervals over the past 2,000 years when SST within IPWP was likely (>66% probability) higher than the 20th century value but that (2) the rate of 20th century warming is likely (>66% probability) unprecedented over the past two millennia.