What's behind the colored snow? - The colored snow is the sign of global environment


Many people love white snow scenery. And interestingly, this white campus also shows the condition of environments. When you see snow with black or any color, it's the sign of environmental crisis.

What’s the cause of colored snow? Snow contains various impurities. One of the main impurities that changes to black snow is black carbon.  Also in Japan,Yellow sand is brought from mainland China. Yellow sand is a grain of sand rolled up in the wind in the Gobi Desert  and the Taklamakan Desert spreading to the west of China.[1] Although there are various kinds of impurities in the snow, black carbon is the one of the big cause of melting snow, raising sea level, and progress global warming.

So How black carbon affects to snow melting?
Usually snow reflects sunlight but when black carbon covers the surface of the snow and ice, snow becomes dark, difficult to reduce radiation. As a result, the melting speed of snow becomes faster. Also heat stays near the earth, and accelerate global warming.[2] Black carbon is sold as de-icer material in the shop. 

The melting toe of the Athabasca Glacier in Canada. 
Photo from The Damaging Effects of Black Carbon

How black carbon is created? The reason why the amount of snow decreased might be not only global warming, but also human economy activities. Black carbon is mainly generated when carbon-based fuels is burned burn such as diesel engine exhaust gas, coal combustion, forest fires, and biomass fuel combustion.[3] Soot is also called a short-lived climate pollutant (SLCP) because it is both an air pollutant and a substance that affects the climate. These have the effect of warming the atmosphere and warming the climate, as well as air pollutants that have a negative impact on human health, agriculture and ecosystems.[4]

So protecting environment also connects to beautiful white scenery too.