A recent study indicates that rapid warming is dramatically impacting northern ecosystems, raising concerns among scientists that local vegetation may be losing its capacity to recover from climatic disruptions.
Researchers found that frequent events such as wildfires, which destroy plant life, along with ongoing challenges like drought and deforestation, have considerably weakened the resilience of various plant communities in southern boreal forests. This diminished ability to bounce back might disrupt the Arctic carbon balance, suggesting a future where this area could transform from a carbon sink, which absorbs carbon dioxide, to a carbon source, releasing more carbon into the atmosphere over the next few decades.
Yue Zhang, the lead author of the study and a graduate student in earth sciences at The Ohio State University, explained that the Arctic and boreal regions have experienced warming significantly faster than other regions worldwide, with additional warming expected soon.
“Often, when discussing how forests respond to climate change, we focus on tropical rainforests,” Zhang noted. “However, remote boreal forests are crucial due to their vast size, substantial carbon storage, and potential for climate change mitigation.”
This research was recently published in Nature Ecology & Evolution.
To comprehend how increased warming has altered the ecosystem, researchers utilized historical data from NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE) project. They remotely assessed subtle changes in vegetation greenness across Alaska and western Canada from 2000 to 2019. This allowed them to gauge how quickly vegetation could recover following minor changes or significant losses, even in areas that haven’t yet experienced major losses.
The study revealed a notable decline in plant resilience in southern boreal forests, although some regions showing greening trends seem to have increased resilience in the Arctic tundra. Besides wildfires, factors such as elevated temperatures and drought could contribute to the reduced plant resilience in southern areas, while shifts in nutrient availability may be promoting vegetation growth in the Arctic.
Although the increased availability of nutrients may foster plant growth and resilience, rising temperatures contributing to this phenomenon could accelerate the melting of Arctic permafrost, releasing as much carbon as the emissions from 35 million cars annually and potentially triggering climate tipping points.
At this time, it remains uncertain how much of the carbon released will be absorbed by plants versus how much will add to further warming, according to Zhang.
“This is concerning because while greening suggests an uptick in productivity and carbon uptake in these regions currently, the decline in resilience indicates this may not be sustainable in the long term,” she stated.
The study indicates that these changes signal a risk to the entire ecosystem, as significant portions of southern boreal forests are losing stability, which could lead to extensive forest decline and changes in biomes.
Regions experiencing greening alongside declines in resilience may indicate that the area is struggling to endure before facing notable forest loss, suggested senior author Yanlan Liu, an assistant professor of earth sciences at Ohio State. This implies that while short-term carbon absorption may be significant, if the trend of declining resilience continues, the Arctic boreal ecosystem might not be as effective at mitigating climate change long-term as previously expected.
“Temperature records indicate this area is warming up to two to four times faster than the global average,” Liu explained. “Studying this region of vegetation change can provide insights into ecosystem stability and its capacity to cope before it shifts to a different state characterized by widespread forest loss.”
Further findings indicated that warm and arid high-elevation areas with dense vegetation were hotspots for resilience decline. However, many climate models currently do not agree on how vegetation change connects with carbon dynamics; this research aims to enhance such models by pinpointing where vegetation changes are likely to occur.
Ultimately, Zhang emphasized that their approach highlighted subtle shifts in the health of the region’s vegetation, beyond previously noted greening and browning trends. This method also serves as a valuable tool for researchers to identify potential vegetation loss in other areas over the coming decades.
In light of their commitment to accurately forecast ecosystem changes, researchers believe their findings necessitate more field studies to enhance understanding of the region’s resilience.
“Scientists must learn to quantify climate-induced risks from various perspectives,” Liu remarked. “In addition to satellite remote sensing, we need more on-the-ground observations to help guide effective resource management and risk strategies based on these discoveries.”
This study received support from NASA and the Ohio Supercomputer Center. Co-authors include Kaiguang Zhao from Ohio State, Jonathan Wang from the University of Utah, and Logan T. Berner and Scott J. Goetz from Northern Arizona University.
