What were the causes for the changes in sea levels on the Earth over time? There are multiple causes that can be divided into two groups: intrinsic, or internal drivers, originating within the Earth’s system, and extrinsic drivers, which originate outside the Earth’s system. Some of these operate over the timeframe of the Earth’s history, and others operate over shorter timeframes. Some influences are global in scale, while others are more regional or localized. The following pages are part of a partial list of these influences. These drivers are also interconnected, with one influencing another in many cases.