Soot and Dirt Is Melting Snow and Ice Around the World

It's easy to imagine new snow 
so bright that we must avert our eyes 
even while wearing sunglasses. 
What scientists are discovering, though, 
is this brilliant whiteness of snow and ice 
is increasingly being dimmed by air pollution....

From Greenland's ice sheets to Himalayan glaciers and the snowpacks 
of western North America, layers of dust and soot are darkening the color 
of glaciers and snowpacks, causing them to absorb more solar heat and 
melt more quickly, and earlier in spring.

This trend toward darker snow from soot and dirt has been observed for years. 
Sources vary from dust blowing off deserts and snow-free Arctic land, 
to soot from power plants, forest fires, and wood-burning stoves. 
But now soot and dust are taking a greater toll, according to a 
report released this week, causing Greenland's ice sheets to darken
—and melt—at a faster rate in spring than before 2009.

This matters because Greenland is mostly covered in ice, and meltwater 
from thawing continental glaciers like those found in Greenland and Antarctica 
flows into the ocean, causing seas to rise. 
Greenland, the world's largest island, holds enough ice that if it all melted 
seas would rise—likely over centuries—up to 20 feet.

This darkening of Greenland ice by soot and dirt will probably cause seas 
to rise faster toward the end of this century than previously forecast. 
(Reports last month indicated portions of the 
Antarctic ice sheet were also melting faster than forecast.)...
[...]news.nationalgeographic.com