When ice from the polar regions melts and flows towards the equator, the mass distribution of the Earth changes. This shift in mass causes in increases in the Earth's moment of inertia. According to the principle of conservation of angular momentum, if the angular momentum ( L=Iω ) remains constant and the moment of inertia ( I ) increases, the angular velocity ( ω ) must decrease. A decrease in angular velocity means the Earth rotates more slowly, leading to an increase in the duration of a day.