On the time scale of the entire history of the Earth, denudation rate is controlled by the tectonic processes that supply fresh bedrock to the subaerial Earth-surface environment. There are two important aspects to this. One is the uplift of mountains and volcanism to produce steep terrains that undergo weathering-limited erosion. The other is the rise and fall of global sea level that affects erosion and sedimentation on the cratons. Low sea level equates with erosion of the cratons. High sea level equates with cessation of erosion and even sedimentation on the cratons. Glaciers are the most potent agents of physical erosion on cratons and perhaps in mountain terrains were the bedrock is resistant to chemical weathering. The role of continental ice sheets in excavating shield over the history of the Earth deserves further consideration.