A possible effect of ice ages on the Earth's magnetic field

ICE ages and reversals of the Earth's magnetic field are two widely different geophysical phenomena; but they may be casually linked by the following mechanism. The moment of inertia of the Earth will be changed by variations in size of polar ice sheets and the resulting redistribution of water mass. To conserve angular momentum the Earth's rotation must therefore change. Calculations on the basis of a simple model then suggest that conditions at the core–mantle boundary may be perturbed in such a way as to affect the generation of the Earth's magnetic field.