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Italy's melting glaciers face new threat: Pink ice


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Italy's melting glaciers face new threat: Pink ice

Glacier scientists are investigating the appearance of pink ice at Italy's Presena Glacier, an Alpine region known for skiing and outdoor sports. Research suggests the algae could

 

contribute to increased glacial melt.

 

Striking photos and videos have been making the rounds on social media in recent days, with people marveling over the appearance of pink ice in the Italian Alps.

 

The colored ice — known as "watermelon snow" — has been spotted at the Presena Glacier, a popular winter sports area in Italy's northern Trentino region, which is already feeling

 

the effects of climate change. The area has seen at least 15% of its glaciers retreat since the beginning of the century, and researchers are now looking into whether the

 

proliferation of this natural phenomenon, caused by algae, could speed up the melting process even further.

 

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The pink ice is caused by a naturally occurring algae, common to snowy regions around the world

 

Key facts

    Even if we act swiftly to curb carbon emissions in the coming decades, more than a third of the world's remaining glaciers are expected to disappear by the end of the century


    Glaciers in the European Alps have shrunk by about half since 1900, according to the European Environment Agency. Climate scientists have warned the Alps could be ice free

 

by 2100 if nothing is done to curb CO2 emissions


    Algal bloom — more commonly associated with the world's oceans — also darkens the surface of glaciers, increasing the amount of sun they absorb and, therefore, how

 

quickly they melt


    The algae found in Italy, likely Chlamydomonas nivalis, are quite common in the Alps and snowy regions around the world, according to Biagio Di Mauro of Italy's National

 

Research Council

 

Algae: Bad news for glacial melt

 

Algae found in the Alps remain dormant during the winter, and only begin to spread on the ice in the spring and summer months when conditions are ideal: increased light and

 

nutrients, plenty of meltwater and a temperature slightly above freezing.

 

It turns shades of pink and red when exposed to sunlight, which causes it to produce a naturally protective red carotene layer to shield it from harmful ultraviolet radiation.

 

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Di Mauro says the ice, darkened by the algae, absorbs the sun's rays and melts faster, eating away at the glacier

 

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Chlamydomonas nivalis, which exhibits its red coloring in the close-up, uses pollutants carried in snow as food

 

But it doesn't just give snow the look of strawberry gelato. Algal bloom can also tint ice shades of brown, violet yellow or green, as seen in a recent survey that analyzed the

 

slushy coastal regions of Antarctica where warmer temperatures and the excrement of marine animals and birds cause it to spread.

 

 

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Initial reports suggested the algae might be Ancylonema nordenskioeldii, a species common on the ice sheet in southwest Greenland. In a paper published earlier this year, Di

 

Mauro wrote about his discovery of the first signs of this algae at the Morteratsch Glacier in Switzerland.

 

"Warm summers and dry winters create the perfect environment for the algae to grow. So, in the future the presence of algae on snow and ice could be favored by climate

 

change," Di Mauro told DW, though he said that remained to be proven.

 

Di Mauro said it was still unclear how the algae had made its way to the Alps from Greenland, or whether it had already spread elsewhere. But, he added, "I would not be

 

surprised to find it on other glaciers in the Alps."

 

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Algae doesn't just color ice red

 

Algae 'spectacular,' but not glaciers' main threat

 

No matter the color, the algae don't help the already endangered glaciers. The bright, white surface of a typical glacier generally has a high albedo, meaning it reflects around

 

80% of the sun's radiation back into the atmosphere. But as the algae spread over the surface of the glacier, it darkens the ice and causes it to absorb more solar radiation,

 

heating the glacier and speeding up the melting process.


This isn't a new problem for glaciers, though. Matthias Huss, a glaciology professor at ETH Zurich, told DW in an email that organic material, dust and combustion residue — soot

 

and ash — can accumulate on glaciers over time and "significantly" reduce their ability to reflect the sun's rays.

 

Huss doesn't think the pink algae will affect "glacier retreat significantly." He said that while the pink algae are "very spectacular," they only last for a relatively short time and

 

aren't very widespread in the Alps. He believes it's possible that algae may contribute to a slight additional reduction in ice volume by the end of the century, but said more

 

research was necessary.

 

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Some ski resorts have begun covering their slopes with insulating tarps in the summer, preserving up to 70% of the snow

 

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On a large scale, however, this would be too expensive and could cause more environmental damage

 

The main cause of glacial melt, however, continues to be climate change. In a 2019 study published by the European Geosciences Union (EGU), Huss said that if nothing is done to

 

curb global CO2 emissions "the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5% or less of the present-day ice

 

volume."

 

The study, co-authored by Huss, Harry Zekollari of the Delft University of Technology and Daniel Farinotti of ETH Zurich, used computer models to examine ice flow and melt

 

processes. It showed that glaciers in the Alps were already on track to lose about 50% of their total volume by mid-century, no matter what happens with emissions. Algae growth

 

did not factor into their projections.

 

'Alps are Europe's water tower'

 

Ice fields are an integral part of the Alpine ecosystem and economy, as they attract tourists and "act as natural fresh water reservoirs" for agriculture and hydroelectricity, said

 

the EGU study.

 

"The Alps are Europe's water tower," said Huss. "If the glaciers begin to provide less water during the summer, this could become problematic in periods of drought." However,

 

he said, given that the glaciers aren't expected to disappear completely before the end of the century, in the worst-case scenario they will likely provide enough water for decades

 

to come.

 

Read more: Hotter, higher seas to worsen extreme floods without 'urgent and ambitious' action: UN

 

According to Zekollari, it might be possible to save "approximately one-third of the present-day [glacial] volume by the end of the century," if the world follows CO2 curbs on par

 

with the 2015 Paris climate agreement.

 

But he said the signs weren't very positive at the moment, with the US abandoning the Paris accord and the EU still stuck in discussions of how it will reach its "ambitious goals."

 

"It is clear that our actions today and decisions we make in the near future will have a large effect on the evolution of glaciers in the second part of the 21st century," said

 

 

 

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