Lights out for the earth? Research reveals dip in brightness of the planet in the past 2 decades

Climate change due to warming ocean waters have caused a drop in brightness of the earth.

It looks like the lights are going off the face of the earth. The brightness of the earth has dropped a bit, says a study. And the reason? Climate change.

The study has pointed out that the warming ocean waters have forced a dip in the brightness of the earth. The study was published in the much-respected AGU journal Geophysical Research Letters.  The findings were based on research that measured the intensity of earthshine, which is the light reflected by the earth and that lights up the surface of the moon. Further, the research also gauged earth’s reflectance over the past couple of decades using satellite mechanisms.

The findings were a revelation. Compared to 20 years ago, the earth currently reflects half a watt less light per square meter. The study also found that a majority of the drop in reflection came about during the last three years of earthshine data.  This in actual terms means that there has been a 0.5 per cent dip in the Earth’s reflectance. If you would remember, science teachers had taught us in school that the earth reflects about 30 per cent of the sunlight that shines on it.

Decrease in bright, reflective clouds over eastern Pacific Ocean

It is common knowledge that the sunlight reaching the earth is related to the sun’s brightness and the earth’s reflectivity. However, the study found that the dip in earthshine did not have anything to do with changes in the sun’s brightness. The culprit was something on the home front, and the meant that researchers were on course to find what caused the earthshine to dip.

Studies regarding this led researchers to come across a reduction of bright, reflective low-lying clouds over the eastern Pacific Ocean. A Physorg report said that satellite measurements made as part of NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project found that this was a recent phenomenon.

The study went on to record that, areas over the eastern Pacific Ocean and off the west coasts of North and South America saw an increase in sea surface temperatures due to the reversal of a climatic condition called the Pacific Decadal Oscillation. This the study suggested could be linked to global climate change.

This apart, the earth’s dimming has also been measured comparing it with how much more solar energy is captured by Earth’s climate system. So, when additional solar energy stays in Earth’s atmosphere and its oceans, the researchers calculated that it could enhance global warming. This, in turn, is seen as serious.

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