Greenland's lakes have drastically changed in just a year, becoming unsightly. What caused this transformation? (photos)

For over a decade, scientists have been monitoring water bodies and have now unexpectedly found that most of them have changed beyond recognition—this has alarmed the researchers.

https://focus.ua/technologies/689717-ozera-grenlandii-vsego-za-god-massovo-stali-urodlivymi-chto-zastavilo-vodoemy-izmenitsya-foto2025-01-23 07:50:10

Historically, Western Greenland is a relatively arid tundra region. In summer, the thawed local landscape is covered with low-growing vegetation, while the permafrost remains frozen beneath the soil. The area is also dotted with thousands of lakes — scientists have counted around 7,486 bodies of water — and a new study has uncovered something quite alarming, reports Popular Science.

Jasmin Saros, a professor of lake ecology at the University of Maine, has been visiting Western Greenland every summer since 2011. She travels to the northern part of the region to gather data on freshwater systems. In 2022, Professor Saros and her colleagues collected samples from the lakes and found nothing alarming overall; however, everything changed the following year.

The researchers note that, generally, things progressed as expected: the results slowly shifted in accordance with climate change, yet the lakes appeared the same — their water was so crystal clear that scientists could see the rocky bottoms. However, in 2023, the situation changed — researchers discovered that the water in one of the lakes had turned a rich tea-brown color. Initially, scientists thought this affected only one body of water, but it turned out to be significantly more — the researchers were alarmed.

The authors of the study point out that the changes were not merely superficial. The results indicate that Greenland's lakes have lost about 90% of their microbial biodiversity, gained 1000% more dissolved iron, and shifted from absorbing carbon dioxide to releasing it.

According to Professor Saros, this transformation was triggered by an especially warm and wet autumn and, most concerningly, may be permanent. In simple terms, the changes in the lakes of Western Greenland likely serve as a striking example of a climate tipping point. Scientists had previously warned that the planet could reach such tipping points, but now we have a vivid illustration.

Typically, research focuses on lakes in the Arctic, as they are significant indicators of climate change and often show alterations first. Previous studies have also shown that the Arctic is warming significantly faster than the rest of the world, but other regions are not immune either — Western Greenland is a troubling example.

Professor Saros and her colleagues analyzed the collected samples and found a series of alarming discoveries:

there is more silt, soil, and plant detritus in the waters;
the level of iron in the water surged by 1000%;
there is an increase in other metals, such as aluminum and cobalt;
bacterial toxins have decreased, while algae have increased;
photosynthesis has decreased;
the level of methane surged by 72%;
the lakes have become new sources of greenhouse gas emissions in the summer — emitting four times more carbon.

The team also attempted to determine the cause of such changes. To do this, scientists studied long-term weather and climate data. The results indicate that in the autumn of 2022, Greenland experienced record heat and precipitation caused by several atmospheric rivers. During the heatwave and heavy rains, a significant amount of permafrost melted, releasing a large volume of organic matter and metals bound in the soil.

According to Professor Saros, this extreme period led to the lakes expanding and becoming more interconnected. Additional heavy rains and heat in July 2023 contributed to this accumulation. Satellite images show that the changes were not specific to the lakes. With the addition of heat and water, the land also transformed, becoming noticeably greener.

It is worth noting that the darkening of lakes is not a new phenomenon. This has occurred many times throughout Earth's history in response to climate shifts and other changes in local conditions. However, previously, all of this happened significantly more slowly than once thought. It is estimated that it would take about 1,000 years for such darkening to occur naturally in a lake. Unfortunately, according to Saros, it remains unclear what conditions or how long it will take for the lakes to return to their former state.