The Earth is less bright than it used to be because there are fewer clouds in the air, a study found

• A study found that the Earth has lost some of its shine over time, a study found.
• They think it is because there are fewer clouds to bounce back the light.
• The phenomenon may have implications for the climate, though that requires more study.

The Earth is bouncing back less light into space because its cloud coverage isn't what it used to be, a study found.

This is due to the cloud coverage being reduced due to a fluctuation in ocean temperatures, the researchers said.

Philip Goode, a researcher at New Jersey Institute of Technology, and a lead author on the study, described his findings to CNN.

"Off the west coast of the Americas, the low-lying clouds were burned away and more sunlight came in, so the way we saw it was, the reflectance of the Earth had dropped," he said.

The study looked at a phenomenon called "earthshine."

The same way that the moon bounces back the sunlight, which gives it that silver-gray look in the night sky, the Earth reflects about 30% of the sunlight, it receives which is why it looks like a blue marble from space.

Scientists are able to measure the reflection of the Earth on the dark side of the moon, which is called earthshine.

The Earth's shine on the moon has been more or less constant over the past 17 years. "We were sort of reluctant to do the last three years of data because it looked the same," Goode told CNN.

But when Goode and his colleagues did look, "the reflectance had...gone down noticeably," he told CNN.

So much so that the scientists at the Big Bear Solar Observatory in California, which has been monitoring the earthshine since the mid-90s, thought they had made a mistake.

"We redid it several times and it turns out it was correct," Goode said.

The scientists found that the Earth's capacity to reflect sunlight - a measurable trait called its "albedo" - has gone down by 0.5 watts per square meter.

That means the Earth is getting 0.5% more sunlight compared to levels in the first decade of the 2000s, per CNN, which is "climatologically significant," the scientists said in the study.

The findings were published in the peer-reviewed journal Geophysical Research Letters on August 29.

The scientists attribute the loss of albedo to there being fewer clouds in the atmosphere to bounce back the light into space.

Specifically, they attribute the change to Pacific Decadal Oscillation, a long-term fluctuation of the Pacific Ocean during which the ocean either warms or cools, influencing the jet stream and weather patterns along the way, per NASA.

A 2016 study found that climate change is also changing cloud coverage, shifting it towards the poles which are affecting the Earth's albedo, Insider previously reported.

However, the scientists didn't mention climate change in the 2021 study.

Speaking to CNN, Goode wouldn't venture the guess on how the loss of albedo could affect the planet.

But Edward Schwieterman, a planetary scientist at the University of California at Riverside who was not involved in the study, said in a statement that it was "actually quite concerning,"

Scientists had hoped that the Earth warming would lead to more clouds in the atmosphere, potentially counteracting some of the warming by reflecting additional sunlight.

"But this shows the opposite is true," he said.