Timing Is Everything

Deep ocean sediments document past environmental changes over space and time. The information gleaned from such deposits allows scientists to test climate models that are used to predict future climate change. However, the causes and consequences of changing climate can be unraveled only if geological data from different regions are synchronized in time so that lead-lag relationships can be properly established. Synchronization of geological archives across regions requires precise and accurate age models, but available age models are often not sufficiently accurate to rigorously test causality arguments. We therefore propose to launch an international, coordinated effort to revise and recalibrate the dating tools available to paleoclimatologists-that is, the local and regional information obtained from bio-, magneto-, and chemo-stratigraphy as well as radioisotopic geochronology-with the synchronizing tool of astrochronology. Cross-fertilization of expertise is needed to generate new age models for sediment records from which key climate events have been or can be reconstructed. We expected this initiative could make a significant contribution to the understanding of Earth history, biotic evolution, and particularly, Earth's climate history.