Milankovitch Cycles and Paleoclimate

First published: 2024

Brief summary

NASA source on orbital forcing in climate history.

Article

Milankovitch cycles are long-term variations in Earth’s orbital geometry that alter the seasonal and geographic distribution of incoming solar radiation. The principal components are eccentricity, obliquity and precession.

Eccentricity changes the shape of Earth’s orbit over roughly 100,000-year timescales. Obliquity changes axial tilt over about 41,000 years, while the combined effects of axial and apsidal precession produce an average cycle of about 23,000 years.

These variations are especially important for summer insolation at high northern latitudes, where cool summers favour the persistence of snow and expansion of ice sheets. Warmer summers favour melting, and feedbacks involving ice reflectivity, greenhouse gases and ocean circulation amplify the response.

Deep-sea sediments, ice cores and other paleoclimate records contain variations that correspond with orbital frequencies. Orbital forcing is widely accepted as an important pacemaker of glacial–interglacial change, although it does not explain the rapid warming of 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/