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

Abstract

Climate variability in the tropical Pacific Ocean influences climate across much of the planet. A diatom-based record of sea surface temperatures from El Junco lake, Galapagos, reveals that the most recent half-century is the warmest 50-year period in the past 1,200 years. Through its intimate connection with the El Nino/Southern Oscillation system, climate variability in the tropical Pacific Ocean 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 records1,2 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 climate3,4,5. Here we use a diatom record from El Junco Lake, Galapagos, 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.