Milankovitch oscillations, also known as Milankovitch cycles, are long-term variations in Earth’s orbit, axial tilt, and precession that are believed to be related to changes in Earth’s climate over geological time scales.

Get the full solved assignment PDF of MEVE-011 of 2023-24 session now.

These cycles are named after the Serbian scientist Milutin Milankovitch, who developed the theory in the early 20th century. The Milankovitch oscillations are considered one of the factors influencing Earth’s climate variability and the timing of ice ages.

The three main components of Milankovitch oscillations are:

Eccentricity:

Eccentricity refers to the shape of Earth’s orbit around the Sun. The Earth’s orbit is not a perfect circle but an ellipse, and eccentricity measures the deviation from a perfect circle. Eccentricity varies over time, transitioning between more elliptical and more circular shapes. This cycle has a periodicity of about 100,000 years.

Obliquity (Axial Tilt):

Obliquity refers to the tilt of Earth’s axis relative to its orbital plane around the Sun. The axial tilt varies between approximately 22.1 and 24.5 degrees over a cycle of about 41,000 years. Changes in obliquity affect the distribution of solar radiation received at different latitudes, influencing seasonal variations and climate patterns.

Precession:

Precession involves the gradual shift in the orientation of Earth’s axis of rotation. Instead of pointing toward a fixed point in space, the axis traces out a circular path over time. The precession cycle has a periodicity of about 26,000 years. The changing orientation of the axis affects the timing of seasons and the distribution of solar radiation.

The combined effects of these three Milankovitch cycles influence the amount and distribution of solar radiation reaching Earth’s surface, which, in turn, can contribute to variations in climate. The Milankovitch theory suggests that the timing of glaciations (ice ages) on Earth is correlated with changes in these orbital parameters.

Key points related to Milankovitch oscillations:

Changes in the Earth’s orbit, axial tilt, and precession influence the amount and distribution of solar radiation received on Earth.
These orbital variations are considered one of the factors contributing to long-term climate changes and the timing of ice ages.
The Milankovitch cycles are relatively predictable and have periodicities of tens to hundreds of thousands of years.
The theory gained prominence in the 1970s when it was proposed as an explanation for the timing of glacial-interglacial cycles observed in paleoclimate records.

While Milankovitch oscillations provide a framework for understanding long-term climate variability, they are not the sole drivers of Earth’s climate. Other factors, such as greenhouse gas concentrations, ocean currents, and volcanic activity, also play crucial roles in shaping the Earth’s climate over different time scales.