EAST PROVIDENCE, R.I. (WPRI) — While ‘sunshine’ is an everyday term, did you know there’s also ‘Earthshine?’
For decades, scientists and researchers have used the term to describe the amount of sunlight reflected by the Earth. ‘Earthshine’ is also what illuminates the darker portion of the moon.
Data collected over decades shows the Earth is losing reflectance, especially over the past 20 years or so.
What’s causing the Earth to become dimmer?
According to a new study, the Earth is dimming, and the cause is relative to the rising surface temperatures of our oceans. The research also pinpoints a specific location on the planet where reflective, low-lying clouds have been reduced in recent years, which is shown by satellite measurements made as part of NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project.
This lack of cloud cover over the eastern Pacific Ocean means more sunlight is reaching Earth and less is being reflected out into space.
The diagram below provides a visual of the sun’s light being reflected off the clouds in our atmosphere. The balance of receiving and reflecting the sun’s light relies on cloud cover. With some cloud cover disappearing in parts of the world, more sunlight is able to reach the Earth’s surface and atmosphere. With more sunlight comes more warming of the Earth.
The Earth typically reflects about 30% of the sun’s light.
How does this connect with ocean temperatures?
According to an American Geophysical Union (AGU) press release, that same area in the eastern Pacific (just west of North and South America) that is seeing less reflective cloud cover has also seen a rise in ocean surface temperatures.
Could this impact climate change?
Another way of viewing the dimming of the Earth is how much more solar energy the planet’s climate system is capturing. The AGU says that once the additional solar energy is in the Earth’s atmosphere and oceans, it may contribute to global warming.