Milankoviin

Milankoviin is a term used for the Milankovitch cycles, the theory that long-term changes in Earth's orbit and rotational dynamics modulate climate on timescales of tens to hundreds of thousands of years. The concept is named after Serbian astronomer Milutin Milanković, who developed a mathematical framework to link orbital variations to changes in solar radiation reaching Earth.

Three orbital parameters drive the cycles: eccentricity, obliquity, and precession. Eccentricity describes changes in Earth's orbit shape, with roughly 100,000-year cycles and a longer ~413,000-year component. Obliquity, the axial tilt, varies between about 22.1° and 24.5° on a ~41,000-year cycle, altering seasonal contrast. Precession is the wobble of Earth's axis, shifting the timing of the seasons with a ~23,000-year cycle. The combined effect changes the distribution of solar radiation, especially Northern Hemisphere summer insolation, influencing ice-sheet growth and retreat.

Historical and scientific significance: Milanković's calculations, published in the early 20th century, proposed orbital forcing as the pacing mechanism for Pleistocene glaciations. Later paleoclimate data from ice cores and sediments supported this view, though climate responses involve CO2, albedo feedbacks, volcanism, and tectonics.

Remarks: Although named after Milanković, the cycles form a general framework widely used in paleoclimatology. While orbital forcing sets the tempo, climate responses are complex and not strictly periodic; internal variability and other forcings modulate the expressed climate states.