Massive and meaty, the Taku Glacier in the Alaska Glacier Field in Juneau is a poster child for frozen places that stand against climate change . As the largest of the region's 20 major glaciers and one of the thickest glaciers in the world (measuring 4,860 feet or 1,480 feet from surface to floor), Takuo massively gained mass and spread further into the nearby Taku River near half a century until all the neighboring glaciers shrink. Now, it seems that these glory days are over.
In a new pair of satellite images shared by NASA's Earth Observatory the slow decline of the Taku Glacier finally became apparent. Taken in August 2014 and August 201
(Image Credit: NASA Earth Obs. (19659007) While shrinking is barely noticeable, the results are shocking, according to glaciologist Mauri Pelto, who has been studying the Juneau Ice Field for three decades, predicting Taku to continue its progress for the rest of the century. the retreats have arrived about 80 years ahead of schedule, Pelto said, but they also silence the symbolic flicker of hope in the race to understand climate change. Of the 250 mountain (or "alpine") glaciers Pelto has explored around the world, Taku is the only one who has not begun to give way clearly.
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"It's a big deal for me because I had this one glacier on which I could hold on, "says Pelto, a professor at Nichols College in Massachusetts, at NASA. "But not anymore. This makes climate change: 250 and alpine glaciers: 0. "
Pelto discovered the withdrawal of the Taku Glacier as part of a new study published on October 14th in Remote Sensing . Using satellite data, Pelto examined an area of the glacier known as the Transitional Snow Line or the place where the snow disappears and glacier ice begins. If a glacier loses more melting mass than it gains from snow accumulation in a given year, its snow line moves to higher altitudes. The relative position of this line can help researchers calculate changes in glacier mass from year to year.
Historical records show that between 1946 and 1988, the Taku Glacier gained mass and progressed (ie, grew) by about a foot a year. Then progress began to slow down and the ice began to thin a little. From 2013 to 2018, progress stopped completely – then in 2018 the glacier finally began to recede. In the same year, Pelto observed the largest mass loss and the highest snow line in the history of Taku Glacier. These changes coincide with the hottest July recorded in Juneau, Pelto writes.
Although it was inevitable that even a glacier as thick as Taku would eventually transition from a period of progression to a retreat, these transitions usually lead to stability after decades where the edge of the glacier does not move at all. Meanwhile, Taku's transition from growth to decay seems to have lasted only a few years.
"The fact that the transition can be so rapid indicates that the climate is dominated by the natural cycle of advancement and withdrawal that the glacier usually goes through," Pelto said.
Originally published by Science live .