Milankovitch oscillations, also known as Milankovitch cycles, are a set of cyclic variations in Earth’s orbital parameters that play a significant role in shaping the planet’s climate and its glacial-interglacial cycles.
These oscillations are named after Serbian mathematician and astronomer Milutin Milankovitch, who first formulated these ideas in the early 20th century. There are three main Milankovitch parameters:
- **Eccentricity**: This refers to the shape of Earth’s orbit around the Sun, which can vary from nearly circular to more elliptical. The eccentricity of Earth’s orbit changes in a cyclic pattern over periods of approximately 100,000 and 413,000 years. When the orbit is more elliptical, it can result in greater variation in solar radiation received by the Earth during its orbit, affecting climate.
- **Obliquity (Axial Tilt)**: Earth’s axial tilt, which is the angle between its rotational axis and the plane of its orbit, varies between about 22.1 and 24.5 degrees over a cycle of approximately 41,000 years. Changes in obliquity can impact the distribution of solar energy across the seasons, affecting climate patterns.
- **Precession**: Earth’s precession refers to the slow wobbling or “precession” of its rotational axis. This wobble has a cyclic period of about 26,000 years. Precession can influence the timing of the seasons, as it changes the orientation of Earth’s axis relative to its orbit.
These orbital variations affect the way solar radiation is distributed on Earth and have a significant impact on the planet’s climate. For example, when eccentricity is high, and the Earth’s orbit is more elliptical, there can be more significant temperature variations between the seasons. Obliquity changes can influence the severity of seasons, while precession can alter the timing of when these variations occur.
The combined effect of these Milankovitch cycles can lead to the onset and duration of ice ages and interglacial periods. These variations in Earth’s orbit and axial tilt influence the amount and distribution of solar energy received by the planet, which, in turn, can drive shifts in climate patterns over long timescales. However, it’s important to note that while Milankovitch cycles provide a framework for understanding long-term climate changes, they do not explain the more recent and rapid climate change driven by human activities, such as greenhouse gas emissions.