Header image: Mountains of Alaska from NASA's B-200 plane as it flew to the Arctic Circle. Credit: Charles Miller
In the far north regions of Earth, where forests stretch across Alaska and Canada, climate change is unfolding at an accelerated pace.
Arctic and boreal regions are warming two to four times faster than the global average, putting immense pressure on ecosystems that absorb CO2 and help slow climate change. Through photosynthesis, vast expanses of vegetation naturally pull carbon from the atmosphere and sequester it in their biomass.
As climate-related disturbances like wildfires and drought intensify, parts of the region may shift from carbon sinks to carbon sources, disrupting the delicate global carbon balance. Understanding exactly how much carbon these ecosystems store or release through their biomass is important for climate mitigation efforts but getting accurate measurements is a challenge.
Two new papers aim to improve how scientists measure biomass across Arctic and boreal zones. Led by University of Utah biologists Wanwan Liang and Jon Wang, one evaluates the accuracy of existing satellite-based datasets, and the other introduces a new biomass map that captures 40 years of ecological change in unprecedented detail.
The research emerged from the Arctic-Boreal Vulnerability Experiment (ABoVE), a NASA-funded, 15-year field research campaign to understand ecosystem change in northern high latitudes.
Making sense of remote-sensing
The first study, published in Environmental Research Letters in March 2026, examines the growing number of satellite-based datasets used to map aboveground datasets across Arctic and boreal North America.
"There are so many datasets out there now, but there's very little guidance for users on how to choose among them," explained Liang, U postdoctoral researcher and the study's lead author.
One major contributor to dataset abundance is the rapid advances in remote sensing technology. Satellites continuously capture images of Earth's surface, and scientists use those data, combined with field measurements, to estimate forest structure, growth and carbon storage.
As the number of datasets has grown, so has confusion about their accuracy and intended use. Different maps often produce different answers, depending on their structure, data sources and landscape coverage.
"Two maps can give completely different estimates for the same region and if you're not an expert, it's really hard to know which one to trust," said Wang, assistant professor in the U's School of Biological Sciences and the study's principal investigator.
To address that problem, Liang and her collaborators conducted a large-scale meta-analysis, comparing nine biomass datasets across North America's Arctic and boreal regions. Rather than declaring a single "best" map, the study identifies which datasets are most reliable for specific uses, from tracking wildfire impacts to estimating national carbon budgets.
"It's more like a guide," Wang said. "Different maps are better for different purposes."
Size of a baseball diamond
Liang also led the development of a new biomass dataset, one of the most detailed of its kind. Built using satellite imagery from the NASA/USGS Landsat program, airborne LiDAR measurements and extensive forest inventory data from the U.S. and Canadian Forest Services, the dataset tracks aboveground biomass annually across nearly four decades. The dataset is described in a paper published in the journal Remote Sensing of Environment on April 30, 2026.
Spanning from 1984 to the present, the map captures changes at a resolution of 30 meters, roughly the size of a baseball diamond. That level of detail allows researchers to detect not only large disturbances like wildfires, but also smaller-scale changes such as logging or land conversion.
"Anything happening at 30 meters or larger, we can detect," Liang said.
The dataset provides a powerful new lens for understanding how northern ecosystems are responding to climate change. By tracking where biomass is increasing or decreasing, scientists can identify the forces driving those changes, be it drought, fire, human activity, warming temperatures or rising atmospheric CO2 concentrations.
This matters because Arctic and boreal forests are potential buffers against climate change. As temperatures rise, scientists have hypothesized that these ecosystems could absorb more carbon, helping offset emissions from fossil fuels. But the reality is far more complex.
"There's been this idea that northern forests will just keep taking up more carbon as it gets warmer," Wang said. "But we don't actually know if that's true."
The same warming that can stimulate plant growth can also increase wildfire frequency and intensity, insect outbreaks and drought stress-factors that boost forest mortality and release carbon back into the atmosphere.
"If plants start to die, they stop absorbing carbon," Liang explained. "And as they decompose, they release CO₂. That would accelerate climate change."
The uncertainty has real-world implications. Governments rely on carbon estimates to inform climate policy and report greenhouse gas inventories. In Canada, for example, national carbon accounting influences how emissions targets are set and evaluated.
"When different datasets give different answers, it creates a lot of uncertainty," Wang said. "And that makes decision-making harder."
Beyond policy, high-resolution biomass maps can help estimate how much carbon might be lost in a fire, identify high-risk areas and guide land-use decisions.
In contrast to some private-sector efforts that restrict access to carbon data, Liang and Wang's project aims to make information transparent and usable for scientists, policymakers, and the public.
"This is taxpayer-funded science," Wang said. "We want people to be able to use it."
Edited from an article originally published by the College of Science.
