Scientists analyzed more than a million satellite images to assess how glaciers melted lakes have been affected by global warming and other processes.
The pictures show the number of glacial lakes that increased by 53% between 1990 and 2018, increasing the Earth’s volume by about 51%. According to the survey, 14,394 glacial lakes cover about 9,000 km किमी of the planet’s surface.
Based on the data, researchers estimate that the amount of glacial lakes in the world has increased by 48% in the same period and now has 156.5 cubic km of water.
“Our findings show how fast the Earth’s surface system is responding to climate change, and the global nature of it,” said Stephan Harrison, a professor of climate and environmental change at the University of Exeter. “More importantly, our results help fill a gap in science because, until now, it was not known how much water was in the world’s glacial lakes.”
Glacial lakes are an important source of freshwater for the world’s poorest people, especially in the mountains of Asia and parts of South America. But the lakes present a growing threat from severe flooding, which can tear down villages, wash roads and destroy pipelines and other infrastructure.
The fastest growing lakes are in Scandinavia, Iceland and Russia, more than double the area in the period studied. Because many lakes are relatively small, increasing the volume globally is not enough.
Elsewhere, such as in Patagonia and Alaska, glacial lakes grow slowly, about 80%, but many lakes in these areas are huge, leading to an absolute increase in water content.
According to the report, published in Nature Climate Change, the three largest Patagonian lakes grew at a much slower rate, but reached 3,582 sq km in 2018, 27 sq km after 1990.
In other areas, the picture was more variable. To the north of Greenland, glacial lakes were rising rapidly, which was more extreme in the global warming Arctic. In southwest Greenland, some of the snowy lakes had shrunk, but often this was because they had already burned.
Although molten water is important for many communities living in valleys beneath glaciers, a sudden eruption from glacial lakes can cause havoc. Writing in the journal, scientists reveal special threats to hydropower plants in the Himalayas; The Trans-Alaska Pipeline, which locates mountains hosting glacial lakes; Major roadways, such as the Karakoram Highway between China and Pakistan, are a corridor that carries billions of dollars of goods annually.
Harrison said, “As the lakes get bigger, they are expected to fill the water quickly and the glacial lake outbreak will increase.” For example, they are a real threat in many valleys associated with repelling glaciers in parts of the Himalayas and the Andes.
“Such snowy lake floods, or GLOFs, have killed thousands over the last century and destroyed valuable infrastructure such as hydroelectric power schemes. However, this is a complex issue. Some lakes become less vulnerable to GLOF triggers as they become larger, but the more water available, the worse it will become if there is GLOF. ”