Scientists are investigating how blood splatter-like spots in snow could be connected to climate change. The reddish dots are made up of tiny algae that grow on snowy mountain ranges. The algae is originally green, but when it’s hit with sunlight, it turns red, creating the eerie blush.
Researchers at the Scientific Research National Center have collected samples of the red snow up in the Le Brévent mountain in France, Reuters reports. The red snow is troubling because scientists have connected the growing presence of the snow algae, which is called Sanguina nivaloides, to elevated levels of carbon dioxide.
Just this month, the National Oceanic and Atmospheric Association reported that CO2 levels in the atmosphere are now more than 50% higher than pre-industrial levels—the highest in millions of years. Global warming is contributing to less mountain snowpack all over the world.
The algae-affected snow can compound the effects of snow loss. Clean snow is one of many natural buffers against the Sun’s heat, as bright white snowpack can reflect over 80% of sunlight, according to NASA, bouncing heat back into space.
However, darker spots in the snow, like dirt and even the red algae, absorb heat instead of reflecting it, which contributes to warming. The heat absorption means that the growing presence of the algae accelerates the snowmelt, which is why researchers are racing to understand the different factors involved in the phenomenon, Reuters reports.
“The warmer it is, the more algae there are and the more the snow melts quickly,” Alberto Amato, a genetic engineering researcher at CEA Centre de Grenoble, told Reuters. “It’s a vicious circle and we are trying to understand all the mechanisms to understand this circle so we can try to do something about it.”