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Study shows Alaska’s landscape is changing quicker than the Lower 48

Map created using Landsat data
Map created using Landsat data(NASA)
Published: Jan. 28, 2021 at 7:50 PM AKST
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ANCHORAGE, Alaska (KTUU) - Satellite data shows Alaska’s landscape is changing quicker than the Lower 48′s.

About 13% of Alaska’s landscape has changed between 1984 and 2015, Research Physical Scientist Neal Pastick, who is a contractor for United States Geological Survey, said.

“That’s an area the size of Wisconsin just a little bit bigger, at 1,800 square kilometers,” Pastick said.

In approximately the last 65 years, the state’s climate has warmed about 2.5 degrees Celsius, which can cause glaciers to retreat and permafrost to melt. However, he said the biggest driver of the change has been wildfires.

To humans, these changes can have serious implications, like flooding, the need to change hunting patterns and villages who use permafrost to keep their food cold, won’t have a natural refrigerator anymore.

Once permafrost begins to thaw, a lot of CO2 and methane can be released into the atmosphere, which creates a positive feedback loop, Pastick said. “So as soon as you start thawing permafrost, you can actually warm up the atmosphere a lot more, causing a cyclical little cycle of never-ending warming. So it’s pretty important to understand where these changes are occurring and why.”

But for animals, it could be good or bad.

“It depends if you’re the caribou that loves eating lichen. It depends if you’re the black bear that loves to forage in recently burned areas,” Pastick said. “As willows start to increase due to climate warming, or summer air temperature increases, moose might be better off. But their counterparts might not. So it really depends on the perspective. If your furry, or scaly or human.”

He said some of these changes have been happening for thousands of years.

“It’s just the rate at which these changes are unfolding now are a little bit faster than what we’ve seen, especially after the 1980s,” Pastick said.

Much of the change isn’t directly human-caused, the permafrost is melting from the temperatures and many wildfires are starting naturally, he said. “But climate warming is definitely driving some of this that we’re seeing.”

The data from the Landsat project was used to find the rate of change.

The program consists of two satellites circling the globe and capturing images of the ground.

Timothy Newman, program coordinator for National Land Imaging with USGS, said one of the satellites revisits a specific spot every eight days, so the data is tracked almost weekly.

The Landsat Program has been collecting data for nearly 50 years, meaning today’s images can be compared to what the land looked like in the 1970s, he said.

Newman said projects like Pastick’s is exactly what the Landsat program was created for.

The purpose of Landsat is to do a global survey of Earth’s surface and “monitor it over time to see the change, detect the change. And then that in turn would give folks on the ground a chance to determine what was the change? What caused the change? Was it a natural change? Was it a human-caused change?” Newman said.

The imagery captures not only what is visible to our eyes, but also infrared imagery, he said.

“That data is used by a wide variety of folks from scientists that study change on the Earth’s surface to farmers that are managing large plots of land, to city managers that are determining where the cities are going to grow out into,” he said. “It’s kind of that Swiss Army knife in space because it has so many different applications for users.”

The next satellite will be launched this year. One of the two already in orbit will be decommissioned.

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