Solar activity and climate

Solar activity and climate is the study of how changes in the Sun’s energy output and magnetic behavior affect Earth’s climate, directly and through atmospheric processes.

Connect

Total solar irradiance: The Sun’s total radiant power received per unit area at Earth’s mean distance. Its small variations alter the energy entering Earth’s climate system.
Sunspot: A relatively dark, cool region on the Sun’s visible surface associated with concentrated magnetic fields. Sunspot counts became a long-running proxy for changing solar magnetic activity.
Medieval Climate Anomaly: A period of regionally varied climate conditions, often relatively warm in parts of the Northern Hemisphere, around 950–1250. Its timing overlaps proposed solar highs, but regional evidence resists a single solar explanation.
Anthropogenic climate change: Long-term climate change caused by human activities, especially greenhouse-gas emissions and land-use change. Its recent warming trend greatly exceeds the small solar contribution observed over the same period.
Ultraviolet radiation: Electromagnetic radiation with wavelengths shorter than visible light and longer than X-rays. Solar ultraviolet varies more proportionally than total output and changes stratospheric ozone.
Solar magnetic field: The magnetic field generated by motion in the Sun’s electrically conducting plasma. Its changing structure underlies solar cycles and many proposed climate pathways.
Little Ice Age: A period of regional cooling and glacier advance, especially from the sixteenth through nineteenth centuries. This historical cooling is often linked to reduced solar activity, though multiple forcings contributed.
Volcanic winter: Temporary global or regional cooling caused by volcanic aerosols that reflect incoming sunlight. Volcanic cooling can coincide with solar minima but arises from a separate atmospheric forcing.
Stratospheric ozone: Ozone concentrated in the stratosphere that absorbs much of the Sun’s ultraviolet radiation. Solar ultraviolet changes can alter ozone and stratospheric temperatures.
Maunder Minimum: A period from about 1645 to 1715 when observed sunspots were exceptionally rare. Its coincidence with parts of the Little Ice Age prompted claims about solar cooling.