Coral Paleoclimatology

The interaction of warm tropical ocean surface waters with the overlying atmosphere on seasonal, interannual, and decadal timescales is the source of climate extremes throughout the tropics and beyond. Tropical cyclones, heatwaves, extreme rainfall, droughts, and El Niño have severe effects on ecosystems and societies globally. Projecting their amplitude and frequency changes in a warming climate requires knowledge of how the tropical ocean-atmosphere system operated in the past.

We use tropical shallow-​water corals to extend the short and rather sparse instrumental record of sea surface observations at monthly resolution. Coral geochemical and isotopic records deliver quantitative information about the fluctuations of sea surface temperature and hydrology on seasonal, interannual, and decadal timescales, with precise chronology. They provide a paleo-observational constraint on climate model simulations of past and future tropical ocean-atmosphere variability.

Our coral-based reconstructions of surface ocean conditions cover time intervals of the recent centuries, the Holocene, the last deglaciation, and the last interglacial warm period. Our work combines ultra high-resolution coral reconstructions, novel analytical techniques, advanced statistical methods, and Earth system modeling in order to contribute to improved projections of tropical marine climate variability and the future of coral reef ecosystems.