Greenland darkens and after being less white, it reflects less sunlight, which contributes to its warming, according to a study.
Greenland’s ice cap has warmed by at least 2.7 degrees Celsius since 1982. This has led to the rapid melting of the ice, according to a study published in Geophysical Research Letters.
And for a decade, satellite observations have shown that the proportion of reflected light from snow, known as albedo, is declining. As a result, Greenland darkens and becomes warmer.
But the reason for this color change has so far been a mystery. Was it caused by the presence of light-absorbing particles in the snow, such as soot caused by burning fossil fuels or something else?
To answer this question, scientists from the American University “Dartmouth” traveled hundreds of kilometers in Greenland in two sampling campaigns – in 2016 and 2017.
The size of the snowflakes, the way they reflect light, and the debris present in the snow have been measured in dozens of places. Scientists have concluded that soot pollution is not to blame for the observed phenomenon.
According to Gabriel Lewis, one of the authors of the study, the Greenland snow is among the cleanest in the world. So the culprit for the warming was sought elsewhere.
Finally, it was identified as an atmospheric blockage. This is a climatic phenomenon that can last for several weeks over some regions of Greenland. It is expressed in a change in air circulation and significantly reduces snowstorms, and they are vital.
“When the snow falls and stays on the surface, it changes shape and the snowflakes get bigger,” Lewis said. “After just a few days, the reflectivity of the snow changes as it drops significantly. That’s why the presence of fresh snow is so important to avoid warming and melting glaciers.”
This year, the melting of Greenland ice forms about 40% of the total rise in the world’s oceans. If Greenland’s ice cap melts, it will raise sea levels by more than 7 meters. At first glance, it may not seem like much, but in reality, it will have catastrophic consequences. Many of the world’s most densely populated regions will remain underwater, including the Netherlands, northern Germany, parts of New York, Philadelphia, Florida, and a vast area of eastern China.
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