According to the data, the Earth is getting dimmer and dimmer as warming oceans block light from being reflected off-planet – trapping even more energy in our atmosphere

Do you ever think about what the Earth looks like from the moon? ‘Earthshine’, also known as albedo, is the lunar experience of this planets’ light, glowing in the black expanse of space. It is what astronauts see when they look to their home planet.

Earth reflects about 30% of the sunlight that shines on it.

Now, ‘earthshine’ data collected by the American Geophysical Union show that there is a trend of dimming – with the albedo decreasing as climate change increases. The light emitted by the planet has decreased by 0.5%.

“The albedo drop was such a surprise to us when we analyzed the last three years of data after 17 years of nearly flat albedo,” said Philip Goode, a researcher at New Jersey Institute of Technology and the lead author of the new study, referring to the earthshine data from 1998 to 2017 gathered by the Big Bear Solar Observatory in Southern California.

How are the oceans connected to the light of Earth?

There have been less reflective low-lying clouds over the eastern Pacific Ocean in the most recent years- according to satellite measurements made as part of NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project.

That’s the same area, off the west coasts of North and South America, where increases in sea surface temperatures have been recorded because of the reversal of a climatic condition called the Pacific Decadal Oscillation.

This is highly likely to be happening because of global climate change.

Does the dimmer light matter?

Yes. 

The dimming could contribute to global warming, even if the increase would be relatively gradual – extra sunlight is still being trapped in the atmosphere of Earth.

“It’s actually quite concerning,” said Edward Schwieterman, a planetary scientist at the University of California at Riverside who was not involved in the new study. For some time, many scientists had hoped that a warmer Earth might lead to more clouds and higher albedo, which would then help to moderate warming and balance the climate system, he said.

“But this shows the opposite is true.”

Read the full study here.