Climate change, as it is commonly used, refers to global warming—the ongoing rise in global average temperature—and its effects on the Earth’s climate system. In a broader sense, climate change includes previous long-term changes to the Earth’s climate. The current rise in global average temperature is faster than previous changes, and it is primarily the result of humans burning fossil fuels.
Alaska appears to be a pristine wilderness untouched by humans from the window of a NASA Gulfstream III research aircraft. The land is lush green with lush vegetation and dotted with bright blue lakes. Snow-capped mountains reach for the sky, and rivers the color of chocolate milk snake across the landscape. Cities, roads, and infrastructure are obvious signs of human activity.
However, upon closer inspection, some hints of human-induced change emerge. Land that has been sunk. Trees that are unusually tilted. Ponds where there was once dry land The signal is clear, according to scientists collecting data from the ground and the air: the Arctic is being affected by climate change more than most other places on Earth. Since 2015, scientists participating in NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) have been studying the impacts of climate change on Earth’s far northern regions and how those changes are intertwined.
“ABoVE is a large-scale study of environmental change, not just climate change,” said Peter Griffith, a carbon cycle researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and one of the leaders of ABoVE. “And we’re doing this as only NASA can: by studying this region from leaf to orbit.”
Previous field and airborne campaigns focused on things like changes in plant cover and shifting animal migration patterns. In the summer of 2022, the team investigated permafrost thaw, methane emissions from lakes, and the effects of wildfires in Alaska and northwestern Canada. They did this with instruments observing from research aircraft and with scientists collecting measurements on the ground.
ABoVE is a large-scale study of environmental change, not just climate change. And we’re doing this as only NASA can: by studying this region from leaf to orbit.
Peter Griffith
Studying Arctic Changes from Air and Space
One of the key components of ABoVE is the airborne campaign, which uses research aircraft like the NASA Gulfstream III airplane. This year the plane was mounted with the Uninhabited Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, which sends out pulses of radio waves that reflect off of Earth’s surface and give scientists an accurate idea of the shape of the land and water surfaces below—even when looking through clouds or thick vegetation.
Each year members of the ABoVE team fly over their field sites, as well as wildfire burn scars and other areas of scientific interest, allowing them to compare measurements taken from both the air and ground. They also revisit sites from year to year to see how the landscapes evolve over time.
UAVSAR is similar to the main instrument on an upcoming satellite. The NASA-ISRO (NISAR) satellite will be a joint mission between the Indian Space Research Organization and NASA to observe Earth’s land and ice. NISAR is also part of NASA’s upcoming Earth System Observatory.
“ABoVE and UAVSAR give the research community a really good example of what NISAR data will look like and what kind of science they can extract from these datasets,” explained Franz Meyer, a NISAR science team member who also is the chief scientist of the Alaska Satellite Facility in Fairbanks.
NISAR will collect data globally and year-round, allowing research groups like the ABoVE team to study critical processes—the development of methane emission hotspots, how and where permafrost is thawing, long-term consequences of wildfires—even when they can’t be there in person.
Thawing Permafrost is Making New Lakes, New Methane Hotspots
Permafrost, or soil layers that have remained frozen for at least two years, underpins much of Alaska and northwest Canada. Permafrost covers much of the landscape in some places, particularly near the Arctic Circle. This frozen soil can be found in patches in other places. In any case, it has remained mostly frozen for thousands of years. However, as our planet warms, permafrost is thawing faster. This is altering the shape and vegetation of landscapes, as well as creating new ponds and lakes, which are also hotspots for greenhouse gas emissions.
When the hard, frozen permafrost layer warms, it changes into softer, spongier ground. That mushy ground sinks and can damage roads, houses, and other infrastructure sitting on top of it. In some areas like interior Alaska, the permafrost layer also contains large chunks of ice. As permafrost thaws and this ice melts, the resulting sinkholes can fill with the meltwater and form new ponds and lakes.
The warmer temperatures that cause permafrost to thaw also increase the activity of microbes that digest dead plants and other thawed organic matter. This microbial decay releases methane, a potent greenhouse gas that bubbles to the lake surface and enters the atmosphere.
This thawing process is happening all over Alaska and northwestern Canada, which already has millions of lakes and ponds. But most of these lakes are hundreds or thousands of years old, meaning the microbes have run out of organic matter to decompose and the lakes are no longer releasing significant amounts of methane.
In 2022, the ABoVE team closely examined Big Trail Lake, just outside of Fairbanks. “Lakes like Big Trail are new, young, and important because they are what’s going to happen in the future as the climate changes and permafrost thaws,” said Katey Walter Anthony, an ecologist at the University of Alaska-Fairbanks working with the ABoVE team.
Arctic and Boreal Fires are Becoming More Extreme
Year-to-year observations from the sky and the ground are especially important for understanding the evolving impacts of wildfires on Arctic and boreal landscape. Fires have long been a natural part of these ecosystems. But as Earth’s climate changes, wildfires in these areas are becoming larger, more frequent, and more severe. This can make it difficult for ecosystems to recover after a fire—changing the plants that grow back and accelerating permafrost thaw.
Fires in Alaska and northwestern Canada may differ from those in the continental United States. The soft, peaty layer of soil and organic material above the permafrost layer is flammable, and this causes the ground to burn at times. Furthermore, fires in remote areas are usually left to burn themselves out unless they threaten houses or other infrastructure. This provides scientists with a “natural experiment” to study how fire burns.
“These tundra fires are so rare that we don’t always get a great opportunity to study them,” said Liz Hoy, a wildfire researcher at NASA Goddard and one of the project’s lead scientists.
