Unprecedented recent warming of surface temperatures in the eastern tropical Pacific Ocean

Through its intimate connection with the El Nĩo/Southern Oscillation system, climate variability in the tropical PacificOcean influences climate across much of the planet. But the history of temperature change in the tropical Pacific Ocean during recent millennia is poorly known: the available annually resolved records are discontinuous and rarely span more than a few centuries. Longer records at coarser temporal resolution suggest that significant oceanographic changes, observed at multi-year to multi-century resolution, have had important effects on global climate. Here we use a diatom record from El Junco Lake, Galápagos, to produce a calibrated, continuous record of sea surface temperature in the eastern tropical Pacific Ocean at subdecadal resolution, spanning the past 1,200 years. Our reconstruction reveals that the most recent 50 years are the warmest 50-year period within the record. Because our diatom-based sea surface temperature index resembles Northern Hemisphere temperature reconstructions, we suggest that with continued anthropogenic warming, the eastern tropical Pacific Ocean may continue to warm. © 2009 Macmillan Publishers Limited. All rights reserved.