A new study indicates that rapid warming is profoundly affecting the northern ecosystem, raising concerns that vegetation in the area may struggle to bounce back from climate-related stresses.
Researchers found that repeated disturbances such as wildfires, which devastate plant life, along with ongoing drought and deforestation, are severely diminishing the resilience of various plant communities in southern boreal forests. This decline in rebounding capacity may disrupt the Arctic carbon budget, suggesting a future scenario where the area could transform from being a carbon sink to a carbon source, limiting its ability to absorb atmospheric CO2 in the upcoming decades.
Yue Zhang, the study’s lead author and a graduate student in earth sciences at The Ohio State University, noted that Arctic and boreal regions are warming several times faster than the global average, and further warming is anticipated soon.
“Often, when we discuss how forests respond to climate change, we focus on tropical rainforests,” Zhang explained. “However, the extensive boreal forests are crucial due to their massive size, substantial carbon storage, and potential for climate mitigation.”
The research was published in Nature Ecology & Evolution.
To comprehend the ecological changes caused by rising temperatures, the researchers analyzed historical data from NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE). They used remote sensing techniques to detect subtle variations in greenness in Alaska and western Canada from 2000 to 2019. This analysis allowed them to gauge how quickly vegetation could recover from either small variations or substantial losses, even in areas that have not experienced major losses yet.
The study indicated that while the resilience of plant communities in the southern boreal forests notably dropped, resilience seemed to have improved in most Arctic tundra areas. Factors like heat and drought, alongside wildfires, may have contributed to decreasing plant resilience in the southern regions, whereas changes in nutrient availability seemed to support vegetation growth in the Arctic.
While nutrient release may enhance plant growth and resilience, the associated rising temperatures could also lead to a quicker thawing of Arctic permafrost. This thawing could release as much carbon as 35 million cars emit annually, accelerating the onset of critical climate tipping points.
It’s currently unclear how much of the released carbon will be absorbed by plants and how much will exacerbate global warming, Zhang stated.
“This is quite worrying, as greening might reflect increased productivity and carbon absorption now, but the drop in resilience suggests that this situation may not be sustainable long-term,” she added.
The study indicated that these ecological changes are signs of a precarious system, as a significant portion of southern boreal forests is losing stability, raising the risk of widespread forest loss and alterations in biomes.
Regions experiencing simultaneous greening and resilience decline could indicate that they are nearing a critical point before substantial forest loss occurs, according to Yanlan Liu, the study’s senior author and assistant professor of earth sciences at Ohio State. This suggests that while these areas might absorb considerable carbon in the short term, if resilience continues to fall, the Arctic boreal ecosystem may not be as effective in long-term climate mitigation as previously thought.
“Temperature records illustrate that this area is warming at a rate two to four times faster than the global average,” Liu noted. “This is a hotspot for vegetation transformation, and studying it can provide insights into ecosystem stability and its tolerance limits before substantial forest loss occurs.”
The study further demonstrated that warm, dry regions with high elevation and dense vegetation were among those experiencing the most resilience decline. However, because existing climate models often lack clarity regarding the interaction between vegetation changes and carbon cycling, this team’s research aims to improve those models by highlighting where vegetation changes are likely to happen.
Ultimately, Zhang stated, their methodology revealed deeper insights into the health of the region’s vegetation beyond the previously noted greening and browning. This approach also equips researchers with a tool to forecast potential vegetation losses in other regions over the next few decades.
As they plan to enhance their predictions regarding ecosystem changes, the researchers emphasize the need for further field studies to better assess and comprehend the region’s resilience.
“It’s imperative for scientists to learn how to gauge climate-induced risks from diverse perspectives,” Liu emphasized. “In addition to satellite remote sensing, more ground-level observations are essential to help us identify strategies for utilizing these findings in future resource and risk management.”
The study received support from NASA and the Ohio Supercomputer Center. Co-authors included Kaiguang Zhao from Ohio State, Jonathan Wang from the University of Utah, and Logan T. Berner and Scott J. Goetz from Northern Arizona University.
