Greenland was for centuries synonymous with immobility, a territory that seemed oblivious to the passage of time, protected by an ice sheet so vast that even polar explorers could see it. like something eternal. From the first Inuit settlements to the European expeditions of the 19th century, the island was more a symbol of resistance than change, a place where the landscape imposed its own rules. Precisely for that reason, any alteration On its surface today it has a historical weight that goes far beyond what appears at first glance.
A dark spot on the ice. Something seemingly insignificant is growing on the immense Greenland ice sheet, but with a disproportionate effect: microscopic algae that dye the snow green, red or grayish brown and reduce its ability to reflect solar radiation.
In a warming Arctic up to four times more faster than the rest of the planet, this so-called “dark zone” accelerates the loss of hundreds of billions of tons of ice each year, directly contributing to sea level rise and adding a new layer of complexity to an already destabilized climate system.
Dust, nutrients and a cycle. counted the new york times last week that much of the latest research shows that the wind blows phosphorus-rich dust from the rocky fringes discovered on the margins of Greenland into the ice, fueling algal blooms.
Here’s the crux of it all, because as the ice melts, also releases trapped nutrients for decades or centuries in its deep layers, creating a kind of vicious cycle: one where more melting releases more food, algae proliferate, the ice darkens and melts even faster.
This mechanism, time and time again, turns warming into a self-accelerating process that is difficult to stop once it has started.
The measurable impact of a microscopic phenomenon. In southwest Greenland, one of the fastest melting regions, algae already explain about 13% of runoff water generated by summer thaw.
In fact, studies published in journals such as Environmental Science and Technology and Nature Communications have shown that even minute amounts of phosphorus and nitrogen, released from the ice or transported through the air, are enough to sustain these biological communities, suggesting that the phenomenon could extend to areas much wider of the cap.
A climate problem. Plus: ice darkening does not occur in a political or economic vacuum. The retreat of sea ice around Greenland is opening new sea routes and facilitating access to mineral, oil and gas resources, increasing the strategic interest for the region.
Any additional industrial activity could release, for example, soot and particles that further aggravate the darkening of the ice, accelerating a process that, in the worst case scenario, could contribute to a global rise in sea level of up to seven meters if the ice sheet completely disappeared.
What is known… and what is not yet. The scientists match in which algae are not the cause of global warming, but rather a consequence which amplifies its effects, while underlining that the root of the problem continues to be the burning of fossil fuels on the planet.
However, it is still unknown precisely to what extent this “dark spot” can expand and how to integrate your impact in sea level rise models. Meanwhile, Greenland seems to offer us a most ominous warning (another one): that even the smallest changes, those invisible to the naked eye, can tip the balance of one of the largest and most fragile systems on the planet.
Image | Jenine McCutcheon/University of Waterloo
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