Nature 424, 271-276 (17 July 2003) | doi:10.1038/nature01779; Received 17 March 2003; Accepted 30 May 2003

El Niño/Southern Oscillation and tropical Pacific climate during the last millennium

Kim M. Cobb1,2, Christopher D. Charles1, Hai Cheng3 & R. Lawrence Edwards3

  1. Scripps Institution of Oceanography, University of California-San Diego, La Jolla, California 92093, USA
  2. Minnesota Isotope Laboratory, Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
  3. Present address: California Institute of Technology, MC 100-23, Pasadena, California 91125, USA.

Correspondence to: Kim M. Cobb1,2 Email:
The monthly Palmyra coral delta18O data are available at (


Any assessment of future climate change requires knowledge of the full range of natural variability in the El Niño/Southern Oscillation (ENSO) phenomenon. Here we splice together fossil-coral oxygen isotopic records from Palmyra Island in the tropical Pacific Ocean to provide 30–150-year windows of tropical Pacific climate variability within the last 1,100 years. The records indicate mean climate conditions in the central tropical Pacific ranging from relatively cool and dry during the tenth century to increasingly warmer and wetter climate in the twentieth century. But the corals also document a broad range of ENSO behaviour that correlates poorly with these estimates of mean climate. The most intense ENSO activity within the reconstruction occurred during the mid-seventeenth century. Taken together, the coral data imply that the majority of ENSO variability over the last millennium may have arisen from dynamics internal to the ENSO system itself.