JUL 22, 2015

Snirt: Does Dirty Snow Melt Faster?

WRITTEN BY: Brenda Kelley Kim
In the summer the conventional wisdom is to wear light colored clothing. When it's hot, the last thing you want to wear are black pants or a black blazer. Warm weather is for pastels and lightweight fabrics. Unfortunately, the Earth's surface doesn't have the luxury of changing its surface colors to suit the climate.

A recent study from NASA has shed new light on what scientists call "Snow Darkening Effect" or SDE for short. The simple version is that dark colors heat up faster than light colors. The longer explanation is that the numbers matter and data collected by NASA satellites can be extrapolated to explain some parts of climate change. Snow is white, but when it's not, it's going to melt faster, but the numbers tell the whole story.

The study, conducted with the use of a NASA computer model of environmental data that included temperatures, melting rates and lots of other big data input, gave scientists quite a bit to think about when it comes to ice temperatures and accelerated ice melting. It's basically all about the numbers.

NASA has a lot of satellites and some of the data they collect is fed into a computer model known as the GEOS-5 climate model. The team, which consisted of scientists and researchers from Japan, Korea and the United States added data to that model to reflect the darkening of snow by various pollutants. The three main pollutants that were studied were dust, black carbon and organic carbon.

Dust comes from a variety of sources on Earth that occur naturally, but the carbon contribution is more complex. Black carbon is the result of burning fossil fuels such as gasoline, oil and coal. Organic carbon comes from the burning of biofuels such as forests and other renewable energy sources. When taken all together, the resulting fallout of dark aerosols that reach the Earth's surface means that the surface temperatures of some areas can rise as much as 10 degrees Fahrenheit

The study results showed that each factor played out differently depending on the area being studied. Dust, a normal environmental factor in lots of different areas was a significant contributor to surface warming in the western Himalayas and Central Asia. Black carbon, mostly from fossil fuels, increased the snow darkening effect mostly in Europe and the eastern portions of Asia and the Himalayas. The effect of snow darkening as a result of organic carbon was the lowest of the three factors, however it was still preset in the areas of Southern Siberia, north eastern Asia and the western part of Canada.

In a statement form NASA, research scientist Teppei Yasunari from the Goddard Space Center in Maryland said, "As we add more of these aerosols to the mix, we are potentially increasing our overall impact on Earth's climate,"

The study, based on a computer model of data run on NASA computers was published on June 15, 2015 in the Journal of Geophysical Research. Check out the video below to learn more about the effect dirty snow has on global surface temperatures