New study finds the world’s glaciers contain far less ice than previously thought, raising concerns for some communities that rely on seasonal melting.
Advances in satellite technology have revealed that the world’s glaciers contain significantly less ice than previously thought, according to a study published in Nature Geoscience.
The revised estimate reduces global sea level rise by 3 inches (7.62 centimeters) if all glaciers were to melt.
But this raises concerns for some communities that rely on seasonal melting of glaciers to feed rivers and irrigate crops. If glaciers contain less ice, water will run out sooner than expected.
While some ice naturally melts throughout the year, rising temperatures due to climate change are accelerating glacier refuge. Between 2000 and 2019, these ice rivers lost about 5.4 billion tons.
Countries are already struggling with glaciers disappearing. Peru is investing in desalination to make up for declining fresh water. And Chile hopes to create artificial glaciers in its mountains.
“We had a rather poor understanding of how much ice is actually stored in glaciers,” said lead study author Romain Millan, a glaciologist at the Grenoble Alpes University. Previous analyzes, for example, double-counted glaciers along the periphery of the Greenland and Antarctic ice sheets, which overestimate ice volume.
The Nature Geoscience study, published Monday, determined how fast glaciers move across the landscape, or their velocity. Such measurements allow scientists to measure volume more accurately, as the way glaciers flow indicates where ice is thick or thin. But the collection of this information is limited by technology.
However, high-resolution satellites deployed in recent years have made the first analysis possible of how 98 percent of the world’s glaciers move, “from small glaciers in the Andes to massive glaciers in Svalbard and Patagonia,” Millan said.
“Our study does not include Greenland and Antarctica, which will be the main drivers of sea level rise in the long run,” Millan told Al Jazeera of Grenoble.
“If we just look at the total volume of the ice sheets compared to the glaciers if the whole of Antarctica were to melt, it has the potential to increase the rise in sea level by more than 50 meters, which is much more than 25 centimeters. of the glaciers, “he said.
The work analyzed more than 800,000 pairs of images of glaciers taken between 2017 and 2018 and found them to be much shallower than previously estimated.
Scientists now estimate that there is 20 percent less glaciers present with the potential to melt into the ocean and raise sea levels. Currently, glaciers account for 1 millimeter of annual sea level rise, or 30 percent of annual rise.
“This is one of the first truly impressive results to emerge” of satellite advancement, says Daniel Farinotti, a glaciologist at ETH Zurich who is not involved in the research.
Millan and his colleagues also found that Asia’s Himalayas contained 37 percent more ice than previously estimated, while South America’s Andean glaciers contained about 27 percent less ice. Already, Peru’s glaciers have lost 40 percent of their surface area since the 1970s.
According to Millan, the parts of the world that will be most affected are the Andes, where the study indicates that there should be less fresh water availability for humans.
“On the contrary, in the Himalayas, we have found that there is probably more fresh water that can reduce the pressure on these resources there,” he said.