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It’s not easy to see aerosols in Earth’s atmosphere,

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but they’re there.

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And NASA scientists say these tiny particles

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are having a profound effect

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on snowpack and spring climate in the Northern Hemisphere.

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At any moment, millions of tons of aerosols lifted by winds

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and generated by wildfires and the burning of fossil fuels

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are traveling across the globe.

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In snow-covered regions,

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certain kinds of aerosols can darken the snow and ice

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causing it to absorb more of the sun’s energy and melt faster.

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Scientists call this phenomenon the snow darkening effect.

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The snow darkening effect is basically another way of saying

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what happens when snow gets “dirty.”

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Snow that has become darkened by aerosols

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absorbs more sunlight, than snow that is pristine.

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This may not seem significant,

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but it can actually have a big effect

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on the melting during spring.

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Using a NASA climate model,

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researchers studied the impact of three types of aerosols

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on snowpack in the Northern Hemisphere spring,

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specifically dust, black carbon, and organic carbon.

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The areas colored red to purple on this map

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show where the surface absorbed more energy from the sun

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due to snow that has become darkened by these aerosols.

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This surface warming resulted in

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reduced amounts of snow in spring,

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shown here in areas colored blue.

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These reductions might reflect an earlier melting of winter snowpack

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and ground warming of areas normally covered by snow.

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In some places,

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temperatures are up to about 10 degrees Fahrenheit warmer

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than it would be if the snow were pristine.

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As we add more of these aerosols to the mix,

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we are changing the makeup of particles in the air and snow,

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potentially increasing our overall impact on Earth’s climate.

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