Earth reflects less light as climate continues to change, reveals new study

Scientists involved in new research have suggested that our planet Earth is reflecting less light than it did in the past, and the reason for this has been accredited to climate change. Published in the journal Geophysical Research Letters, the researchers arrived at this conclusion by observing two decades' old data about a phenomenon called "earthshine". Light from the Earth is reflected due to numerous features that our planet possesses. The oceans, land, clouds, snow, and ice contribute to the reflection of light. Where clouds reflect about half the sunlight that hits them, the oceans reflect very little, while the land is about twice as much. Climate change has made the reflection phenomenon dimmer as ice sheets in the glaciers are melting out of existence, and the clouds which also contribute to the reflection are also getting affected. 

What did the scientists find?

According to a report by LiveScience, the scientists studied the phenomenon "earthshine", where they observed the amount of light reflected by Earth to the Moon's dark side from all the features of our planet. They reportedly combined two data sets: one from NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project from 1997, operating with instruments on different NASA and National Oceanic and Atmospheric Administration (NOAA) satellites. The other data set included the study of fluctuations in "earthshine" since 1998, looking for daily to decadal changes. 

Upon combining the data, it was revealed that the amount of light Earth reflected dropped about 0.5% in just the full two-decade span. This measurement equals half a watt less light per square meter. The earthshine data showed that a major change occurred in just the last three years. Furthermore, the data from 2017 up to 2019 showed even more decline in the rate of reflection. In addition to this, the CERES data revealed that the bright low-altitude clouds over the USA's west coasts and over the eastern Pacific Ocean had also decreased, causing a rise in oceanic temperature. Scientists concluded that this non-reflection of light due to loss of resources should be a concern as the trapped light will only add to the heating of the Earth.

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