Final answer:
An ice age can be triggered by insufficient sunlight reaching the planet's surface, resulting in the accumulation of ice. Changes in the tilt of Earth's rotational axis, Milankovitch cycles, changes in the sun's intensity, volcanic activity, and changes in ocean circulation patterns and Earth's orbit can all contribute to the onset of ice ages.
Step-by-step explanation:
A few factors can trigger an ice age, but generally such climate changes occur when insufficient sunlight is able to reach the planet's surface. Then temperatures drop in northern latitudes, resulting in the accumulation of ice. As the glacial ice sheets grow and spread across the land, water is pulled from the oceans, causing sea levels to drop.
These ice ages were primarily the result of changes in the tilt of Earth's rotational axis, produced by the gravitational effects of the other planets. Milankovitch cycles, which involve changes in Earth's orbit around the Sun, are also believed to play a role in triggering ice ages. Changes in the sun's intensity and volcanic activity are additional factors that can potentially cause cooling and contribute to the onset of ice ages.
Additionally, changes in ocean circulation patterns, shifts in Earth's orbit, and massive volcanic eruptions in the tropics can trigger ice ages as well. For example, the Little Ice Age, which occurred from the 17th to the 19th centuries, was likely influenced by changes in ocean circulation patterns, shifts in Earth's orbit, and volcanic eruptions that released clouds of sulfate particles into the atmosphere.