Reports

The study of past interglacial climates provides valuable insight into natural climate variability under conditions roughly similar to present-day, but with differences in atmospheric pCO2 (1) and astronomic forc-ing. Especially intriguing is a step-like increase in interglacial Antarctic temperature (2), global ice melting (3), and pCO2 (4, 5) that took place at roughly 430 ka and is referred to as the Mid-Brunhes Event (MBE). In order to understand the underlying cause of this shift toward warmer interglacials, it is crucial to establish the global signature of interglacial climates during that time, but sufficiently long records, especially from low latitudes and terrestrial archives, are sparse. Since pCO2 and ice cover affect the planet’s radiative balance, a global change in interglacial climate at the MBE might be expected. While many marine sea surface temperature (SST) reconstructions from around the globe show qualita-tively similar changes to those observed in Antarctica (6), the few avail-able lower-latitude SST reconstructions (7–9) from this time period d