Images of homes and trees collapsing into raging waters in Alaska have become the latest stunning symbols of climate change in a summer of wild weather — this time caused by melting glaciers.
Juneau this week saw flooding that destroyed some houses and caused others to be condemned, while other items such as trees and oil tanks were carried away.
The event was caused by water from Mendenhall Glacier pooling in its Suicide Basin. When the basin fills, it funnels water to Mendenhall Lake, which then ends up in the Mendenhall River.
Aaron Jacobs, a senior service hydrologist with the National Weather Service, said that such water has been released since 2011, but he described this year’s event as “unprecedented” — with river flooding nearly 3 feet above the previous 12-foot record set in 2016.
“We never saw anything like this, this is pretty much unprecedented — how much water came out of the Suicide Basin,” Jacobs said.
This led to “immense erosion,” he added, which took away part of the riverbank, leading homes to become exposed or even fall in.
While it may be difficult to attribute any singular event to climate change, he and other experts said global warming causing ice to melt is a factor in events like this one.
“The climate is warming, and so we have seen a warming environment,” Jacobs said.
“We’ve definitely seen a lot of ice melt and glacier receding and thinning in my time here — about 22 years,” he said.
Ben Orlove, a professor at Columbia University’s schools of international and public affairs and climate, said the glacier is primarily melting because of climate change.
“This is a very well-known and well-understood glacier,” he said. “Its accelerated melting has been observed for decades.”
The Juneau region, where there are several such glaciers, faces risks because of the melting, he said, but noted that the risks may vary between specific valleys in the area.
“These glaciers are coming down from very high mountains … and each of these glaciers comes down a particular valley,” he said. “The risk of flooding is going to vary from valley to valley.”
He said that area fisheries could also be at risk.
Orlove noted, citing the Intergovernmental Panel on Climate Change, that Alaska is expected to see “peak water” — when the most meltwater will be released — between 2050 and 2080.
Orlove said some warming — and related glacial melting — is already baked in, but some of it could be prevented.
“If we stop emitting any greenhouse gases this afternoon, there would continue to be melting because there’s some inertia in the system, but nonetheless, there’s big differences in what we choose to do, particularly in the next five to 10 years.”
“If we move quickly to reduce emissions, we’ll save a lot of ice,” he said.
However, Marco Tedesco, a research professor at Columbia University, said that there is years’ worth of warming already in the atmosphere.
“If you’re cooking a lasagna in the oven, even if you turn on the oven only once, the oven will still be warm,” and the pasta can still be cooked and burned, Tedesco said.
Bruce Raup, a senior associate scientist at the University of Colorado Boulder’s National Snow and Ice Data Center, said that, in general, glacial melt can pose risks to nearby communities around the world.
“Things like this have happened in Peru, certainly in many places in the Himalayas, in Alaska,” Raup said.
But, he noted, that secondary consequences of glaciers and ice sheets melting could impact even more people because of the contribution to rising sea levels.
The floods in Alaska come amid a summer full of weather disasters, including extreme heat that has plagued the southwestern U.S. and other parts of the globe and Canadian wildfires that sent hazardous pollution as far as the Southeast — putting a spotlight on the changing climate.
“It’s telling us how things will be in 20, 30 years — 10 years maybe,” said Tedesco. “I’m actually very surprised at the pace at which the events have occurred this year.”