12/12/14 - Alaska Natives and Climate Change: Melting permafrost threatens infrastructure, homes
Here is the last in KNBA’s 5-part series on Climate Change and Alaska Natives.
As we’ll see, the effects of warming temperatures on infrastructure can be costly and sometimes dramatic.
In much of Alaska, bridges, roads, buildings, and runways have been built on permafrost. That’s soil that became frozen during ice ages from 400 to 10,000 years ago, and a few feet down is frozen rock-hard year around.
Geophysics professor Vladimir Romanovsky, of the University of Alaska Fairbanks Geophysical Institute, said that due to human activity that removes the natural ground cover and warming temperatures, permafrost from the Brooks Range south is becoming unstable. He said when permafrost that’s a mix of ice and soil melts, the water often flows away and the surface sinks.
“It’s not just everything sinking evenly,” said Romanovsky. “But there’s some dips and troughs and all kind of thing develops, which for infrastructure is the worst case scenario.”
The Alaska Department of Transportation and Public Facilities’ chief of maintenance and operations Mike Coffey said as permafrost thaws, it takes more time and money to keep roads in shape.
"When it thaws, then we maintenance and operations spend just about all summer up north fighting the roller coaster ride," said Coffey. "So, we're removing pavement, re-leveling, smooth roads, then repaving or chip sealing back over the top to try to smooth roads out."
Coffey said during most of the 32 years he’s been with the Department of Transportation, Fairbanks winters were cold.
“Historically in the fall they instantly, or very suddenly, went to below zero and they stayed below zero until spring,” said Coffey.
Now, Coffey said, warmer temperatures are changing maintenance requirements for Fairbanks roads.
“We're getting freeze, thaw, freeze, thaw, freeze, thaw. We had a huge rainstorm in January; I think that was in 2011,” said Coffey. “It's forced us to change the way we do our winter maintenance operations in that we’re actually now having to do anti-icing in the Fairbanks area, which 10 or 15 years ago probably wouldn’t have even been thought of.”
Jack Hébert is founder and CEO of the Cold Climate Housing Research Center in Fairbanks. He said melting permafrost can also damage building foundations, putting houses at a tilt or out of square. Sometimes houses sink into the ground, or the soil subsides, leaving stairs dangling above the ground. But Hébert said there are ways to save a structure whose foundation is damaged.
“There’s ways that you can inject material where the ground is starting to subside,” said Hébert. “And actually -- it’s called slab jacking -- you can actually lift parts of the foundation that are failing that can either be done with a fluid, even concrete, or it can be done with a slab jacking foam, and that pushes the foundation back up.
Also in Fairbanks, some hillside residents have seen their wells run dry, and downhill residents’ have seen their basements fill with water as permafrost melts. Hébert said mortgage funders and some municipalities now require soil tests so homes are not built on permafrost at risk of thawing.
Climate change has some people hoping warmer summers and milder winters will become the norm in Alaska. Other effects range from disastrous to inconvenient.
Mike Brubaker, director of the Alaska Native Tribal Health Consortium Center for Climate Change and Health, said people can prepare for the downsides of climate change by increasing local self-sufficiency ̶ food, water, and energy security
“It’s something that’s always been a challenge and always been a priority for small rural Alaska communities,” said Brubaker. “And I think we just have to continue to work on that, and to make sure as opportunity presents itself through construction, through investment, through development that we're making good decisions and helping to make our communities as climate resilient as possible.”
While there may be challenging times ahead, Jack Hébert said he’s still optimistic for the future.
“We can learn and work together on finding ways to address this climatic change that we’re experiencing just as in many other ways we have to adapt to the times we’re living in,” said Hébert. “I think we’ve got the talent to do that up here. It’s going to take research. It’s going to take commitment. Working together, I think we can get there.”
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