When I hear about the thawing of the permafrost, my mind generally goes straight to the greenhouse gases being emitted, and how that’s making the climate crisis that much worse. Maybe I’m in the minority here, but I tend to forget that it also has more immediate effects, down here on the ground. When we talk about changes to mountain snowpack, and melting glaciers, I think a lot of people get that that ties to water shortages either now, or in the not-so-distant future. Permafrost, in addition to holding a vast amount of dead plant matter, also holds a lot of water, and when that melts, it can join in with the snowpack and glacier water to change how the rivers downstream behave.

Streamflow is increasing in Alaskan rivers during both spring and fall seasons, primarily due to increasing air temperatures over the past 60 years, according to new CU Boulder-led research.

This increased volume of free-flowing water during the shoulder seasons is compounded by earlier snowmelt and thawing permafrost, also driven by increasing temperatures; all of which are affecting the formation and safety of Alaska river ice in winter, and the timing of when rivers “break up” in response to seasonal warming each spring.

The findings are the result of a collaboration between researchers at CU Boulder, the United States Geological Survey (USGS) and the National Park Service, who analyzed data from 1960 to 2019 for nine major river basins in Alaska. Their results, published in February in Environmental Research Letters, show how rivers can serve as a measurable quantity for understanding the cumulative impacts of climate change in Arctic regions.

“Measuring rivers is useful because it integrates all these other changes in temperature, precipitation, permafrost and snow cover. All the dynamics that feed the hydrologic cycle eventually get filtered into the amount of water in a river,” said Dylan Blaskey, lead author on the study and doctoral student in civil engineering.

[…]

The researchers analyzed six decades’ worth of monthly data from river gages in nine Alaskan rivers, comparing streamflow to air temperature, soil temperature, soil moisture and precipitation across the basins. They also accounted for large scale climate anomalies, such as El Niño and La Niña.

Streamflow in Alaskan rivers typically peaks in summer, and remains quite low in winter, with stark transitions between the two seasons. The study found that while the amount of water flowing through these rivers on a yearly basis is not changing, when it flows through them is shifting, with more water freely flowing from October through April—creating more gradual seasonal transitions.

Changes in air temperature have had the biggest impact on streamflow in these Alaskan rivers. The average days above freezing in April and October have increased by about a day every decade, according to Blaskey. These months are also when average monthly streamflow has increased the most: by 15% per decade in April and 7% per decade in October.

They also found that the correlation of increased streamflow with temperature is only getting stronger over time when data from the first 30 years (1960–1989) are compared to the most recent 30-year period (1990–2019).

Since the 1960s, winter air temperatures have increased by 7.2 degrees Fahrenheit (4 degrees Celsius) on average across the global Arctic. The findings from Alaskan river gages help quantify the disproportionate impacts that climate change is having on the planet’s northernmost ecosystems.

“One of the opportunities and challenges of researching in Alaska is that signals of climate change have already begun to appear,” said Blaskey.

I’ve been primarily a city-dweller for over a decade now, and I’ve lived in places that don’t tend to have serious water problems yet. That means that while my work has generally kept me aware of what’s happening in the world around me, seemingly small fluctuations in river flow don’t really affect my life in any direct way. For the Indigenous people who have been living off the land in Alaska for millennia, there’s no choice but to deal with these changes:

Indigenous communities use rivers for vital transportation and sustenance, whether frozen in ice or as free-flowing water. Many rivers are part of traditional hunting and fishing routes, which can be traveled over when they are frozen. Rivers also serve as essential thoroughfares to connect communities and to bring in seasonal supplies, such as fuel and food, because road networks are limited in Alaska.

As the seasons shift, ice freezes later and breaks up earlier, undermining the stability and safety of river ice.

“The shrinking of the fall and spring seasons affects how long river ice persists and is safe to travel over. Indigenous communities have suffered an increasing number of fatalities over the last few decades,” said Musselman. “It seemed that everyone at the workshop had stories of someone who had fallen in the ice and lost their life.”

We’re well past the point where the metaphor of the canary in the coal mine is relevant – we’ve been losing actual miners for a while now. Fortunately, if we look to the history of mine safety, we know how to improve things- it’s by organizing and working together. Whether it’s activists or people just trying to go about their lives, we are losing people in this fight. The changes have barely begun, compared to what lies ahead, but the world has already been made measurably less safe in a myriad of small ways that can be difficult to quantify.

Take all of the evidence together, though, and it’s pretty clear that we’re in trouble. Those people who’ve been forced to the bottom, and to the margins of society are getting hit first, as we’ve always known they would, but there’s nowhere that’s not affected now, and it’s only going to keep getting hotter.