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How can changes in the Sun’s energy output affect Earth’s climate?
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Global warming
A series of photographs of the Grinnell Glacier taken from the summit of Mount Gould in Glacier National Park, Montana, in (from left) 1938, 1981, 1998, and 2006. In 1938 the Grinnell Glacier filled the entire area at the bottom of the image. By 2006 it had largely disappeared from this view.
Changes in the Sun’s energy output, or solar irradiance, influence Earth’s climate by altering the amount of energy available to drive atmospheric circulation and heat the planet.12
Mechanisms of Influence
- Direct Irradiance: Variations in solar activity, such as the frequency of sunspots, correlate with decadal to millennial changes in solar output. While the exact physical mechanism remains a subject of study, periods of significantly reduced solar activity—such as the Maunder Minimum—have been associated with cooler climatic periods like the Little Ice Age.13
- Stratospheric Modulation: Changes in solar irradiance, particularly in the ultraviolet spectrum, affect photochemical reactions that produce ozone. This alters the atmosphere's vertical temperature profile, which can influence phenomena such as the strength of winter jet streams.1
- Orbital Cycles: Long-term climate shifts, including the onset of glacial periods, are driven by Milankovitch cycles. These are cyclical changes in Earth’s orbit—specifically eccentricity, axial tilt, and precession—that redistribute the amount of solar radiation received at different latitudes and seasons.4