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IMAGE: Since the discovery that atmospheric carbon dioxide (CO2) concentrations were lower during past ice ages, the cause has been a mystery. Now, Princeton geoscientists Danny Sigman and Ellen Ai (seen. view more
Credit: Laura Pedrick
The last million years of Earth history have been characterized by frequent glacial-interglacial cycles, large swings in climate that are linked to the growing and shrinking of massive, continent-spanning ice sheets. These cycles are triggered by subtle oscillations in Earth s orbit and rotation, but the orbital oscillations are too subtle to explain the large changes in climate. The cause of the ice ages is one of the great unsolved problems in the geosciences, said Daniel Sigman, the Dusenbury Professor of Geological and Geophysical Sciences. Explaining this dominant climate phenomenon will improve our ability to predict future climate change.