Milankovitch Cycles and Earth's Climate
First published: 2024
Brief summary
NASA introduction to eccentricity, obliquity and precession and their role in long-term climate cycles.
Article
Milankovitch cycles are long-term variations in Earth’s orbit and rotational geometry that alter the distribution of incoming solar radiation. The three principal components are eccentricity, obliquity and precession, and each operates on a different timescale.
Eccentricity describes changes in the shape of Earth’s orbit over roughly 100,000 years. Obliquity is the variation in axial tilt, which changes the strength of the seasons over about 41,000 years, while precession changes the direction of Earth’s axis and the seasonal timing of perihelion over approximately 19,000 to 23,000 years.
These orbital changes have relatively small effects on globally averaged annual sunlight, but they strongly influence summer insolation at high northern latitudes. Cooler northern summers favour the survival of winter snow and the growth of ice sheets, while warmer summers favour melting and retreat.
Marine sediments, ice cores and other paleoclimate records show recurring changes that correspond with orbital frequencies. The cycles help explain the timing of glacial and interglacial periods over hundreds of thousands of years, but they do not explain the rapid warming observed during the modern industrial period.
Source details and credits
- Source / publisher: NASA Science
- Source type: Educational article
- URL type: WWW
- Credits: NASA Science
- URL: https://science.nasa.gov/science-research/earth-science/milankovitch-orbital-cycles-and-their-role-in-earths-climate/