The investigators will deconvolute and understand phenomena that produce variations in atmospheric Carbon 14 as a function of time. Knowledge of the time history of Carbon 14 production is essential for dating archeological samples. The cause of these variations may also be diagnostic of processes involved in climate change. The main effort is to examine this variation with high precision measurements of annual tree rings in samples of wood of a known age. Measurements will be made with liquid scintillation counters in an underground laboratory, and by accelerator mass spectrometry. A major goal will be to evaluate the effect of climate change on the upwelling of Carbon 14 depleted carbon dioxide along the western coasts of North America, South America, and Africa.