Albedo is the reflection of sunlight back into space, mainly from bright surfaces such as clouds, snow, ice and atmospheric particles, providing an essential planetary cooling shield.

However, a 2021 NASA study found that the excess of incoming sunlight over outgoing radiation, known as Earth’s energy imbalance, has doubled since 2005. Satellite data reported in this study shows our planet now reflects 1.7 percent less sunlight than 20 years ago, and the decline is speeding up, amplifying global warming.

An international Albedo Accord is needed to reverse the darkening of the world, making sunlight reflection a key climate strategy.

Albedo loss causes about four times more immediate warming than carbon dioxide emissions, according to “Global Warming in the Pipeline,” a 2023 article by James Hansen and colleagues.

With more solar heat entering the Earth system, sunlight that used to be reflected safely back to space is now heating the oceans, land and air. Hansen’s analysis shows that albedo loss is not a subtle background shift — it’s becoming a dominant driver of........

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