Session: Invited talks
Author: Kim M. Cobb / email@example.com / School of Earth and Atmospheric Sciences, Georgia Institute of Technology
Co-author: Pamela R. Grothe, Giovanni Liguori, Emanuele Di Lorenzo, Antonietta Capotondi, Yanbin Lu, Hai Cheng, R. Lawrence Edwards, John R. Southon, Guaciara M. Santos, Daniel M. Deocampo, Jean Lynch-Stieglitz, Tianran Chen, Hussein R. Sayani, Kayla Townsend, Melat Hagos, Gemma O’Connor, Diane M. Thompson, Lauren T. Toth, Andrea L. Moore;
Ocean-atmosphere interactions in the tropical Pacific drive a large spectrum of natural climate variability, and modulate the response of the global climate system to external climate forcing. Newly available datasets of past tropical Pacific climate resolve interannual to millennial-scale variability spanning from the last glacial period to the last century, and their relationship to both internal and external climate forcing. In particular, this study presents new coral-based reconstructions of central equatorial Pacific temperature and hydrology spanning the last seven millennia, with a particular focus on the last millennium. We uncover evidence for a sustained, significant reduction in El Nino-Southern Oscillation (ENSO) variability from 3-5kybp, outlining a new target for simulations of the ENSO’s response to precessional forcing. We also uncover a significant response of tropical Pacific climate to volcanic forcing during the last millennium, focusing in particular on the Samalas eruption of 1258-1259AD. Our new dataset of pre-industrial ENSO activity has significantly lower variance than the ENSO activity of last decades, raising the specter that anthropogenic climate change has already altered the character of ENSO extremes. Lastly, we outline a new strategy for producing continuous, replicated reconstructions of tropical Pacific over the last 1-2 centuries for more robust comparisons with model hindcasts of historical trends in temperature and hydrology in this key region.