Where icebergs are born

In this close-up, Chile's Grey Glacier is decidedly blue. That's because red light has a much longer wavelength than blue light, so reds and infrareds are easily absorbed by the crystalline structure of glacial ice while blues are easily reflected. Optical science aside, glaciers worldwide seem to be singing the blues. Nearly all of them are melting at alarmingly high rates. Grey Glacier has retreated more than a mile since the 1980s, and in 2017 an iceberg measuring 1.5 million square feet calved from the icy giant's face.