The warming process of oceans led to a decrease in the brightness of our planet suggests a recent study.
Researchers analyzed decades of earthshine measurements, the light reflected by the planet illuminating the surface of the Moon, combined with other satellite measurements to discover that there was a considerable decrease in Earth’s reflectance, also known as albedo, over the past twenty years.
Our planet currently reflects roughly half a watt less light per square meter compared to 20 years ago.
The data shows an alarming increase of the drop over the past three years, as per the study published in the AGU journal Geophysical Research Letters.
Earth reflects approximately 30% of the sunlight that strikes it.
The estimates suggest that Earth reflects 0.5% less light than it used to do.
Philip Goode, a researcher from the New Jersey Institute of Technology and study’s lead author, said:
“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.”
When the latest data was compared to that from previous years, a dimming trend was immediately noticed.
The net sunlight reaching the planet is impacted by two factors – the Sun’s brightness, combined with Earth’s reflectivity.
It was also noticed that the variations in Earth’s albedo weren’t lining up with the variations of the Sun’s brightness, meaning that changes in the planet’s reflectiveness are provoked by something within the planet.
From that point, finding a culprit was simple. The conclusion was that the reduction of bright, reflective low-lying clouds over the eastern Pacific Ocean in the most recent years, as reported by measurements made during NASA’s Clouds and the Earth’s Radiant Energy System project.
Interestingly, it’s the same area, off the west coast of North and South America, where the rise in sea surface temperatures was recorded due to the reversal of the Pacific Decadal Oscillation, a climatic phenomenon, which is likely tied to global climate change.