Thursday, April 25, 2019

South American Diary #13: Blue ice


Asia Glacier, Chile

    Pollution does more than merely spoil the environment. As bad as sooty air, plastic-clogged beaches and poisoned rivers are, there's another insidious element that can get overlooked. Pollution gets into your head, into your mind, twisting your expectations of the natural world, so that when I first saw these stupendous glaciers in Chile I thought, "Tide."
     As in detergent. 
    My frame of reference for things that looked like this was blue tinted plastic wrap and blue laundry soap and blocks of old styrofoam. 
Clear glacial ice
    It was difficult enough for the brain to process these enormous sheets of ice, some 200 feet tall and a half mile across. Their tint being, not just pale blue, but a dozen shades of azure, from powder to royal, made it seem not a thing in nature, even though it was entirely natural. Then add the seams of crushed rock, picked up in their slow journeys across the landscape, and the glaciers at first seemed not the pristine wonders they were, but dirty, littered, polluted themselves.  
     It took time to get used to them, to accept their majesty on its own terms and see them for what they are. 
     And more time still to understand where that blue comes from. 
     Powdery snow looks white because it's fluffy, puffed with air, allowing the multifaceted snow crystals to reflect the entire spectrum of colors which, mixed together, look white. (If you don't believe me, take a peek at the classic science class "Newton's disc" experiment).
     Or, better yet, pour yourself a glass of beer. The liquid is brown, the foamy head is white. Why? The bubbles in the foam, reflecting light.
      Glacial ice is old—the snowfalls from 10,000 years, or 100,000, each season compressed for millennia under the crushing weight of the seasons that followed. Over time, the air is pressed out, making the ice very clear, and thus able to let more light in deeper, where it is trapped instead of being reflected, particularly the reds: glacial ice absorbs red light six times more efficiently than blue light, which bounces back into our awestruck and disbelieving eyes. 

Garibaldi Glacier, Chile

   

1 comment:

  1. glaciers are frozen rivers moving towards the sea. Typically they move about 1 meter per day. thats a kilometer about every 3 years. The longest glacier is about 400 kilometers . Some move slower. Some much slower. All the ice in the longest glacier falls into the sea or a lake in about 130 years. For most glaciers its less. For some its more. There is very old ice. Its just not in glaciers

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