Why is Greenland's ice getting darker?

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The ice and snow in Greenland is getting darker and darker since 1981. Scientists have been studying the cause of this problem, and they conlcuded that it's caused by the increase of the solar radiation absorbation. This increase is caused by the global warming, that make the ice melt and reduce the amount of ice, making it darker not only for the absotbing of the radiation, the wildfires of China and other countries are making this effect increase year by years, and now the study is focused on how to stop it.
Investigators say that we must reduce the climate change and reestablish the natural temperature of the planet to make this ice more solid and whiter than now.