Overview

• Satellite records from 2001 to 2024 show both hemispheres reflecting less sunlight, with the Northern Hemisphere drifting by about 0.34 watts per square meter per decade relative to the south.
• The analysis reports a global rise in absorbed solar energy of roughly 0.83 watts per square meter per decade over the study period.
• Declining sea ice and snow cover reduced surface reflectivity in the north, increasing solar absorption there.
• Aerosol loads fell in Europe, the United States, and China, weakening cloud-related reflection in the north, while Australian megafires and the 2021–2022 Hunga Tonga eruption boosted southern aerosols and reflectivity.
• Atmospheric and oceanic circulation plus cloud responses did not fully compensate for the shift, leaving an estimated 0.21 watts per square meter per decade residual in the north and prompting calls to refine climate models.