For years, scientists have pointed to warming permafrost in the Arctic tundra as a source of increased carbon in the atmosphere; As this soil warms, it releases greenhouse gases that have been trapped in the frozen soil.
New research from Northern Arizona University shows that even more carbon is released from thawed permafrost than climate scientists previously thought.
Professors César Plaza, Christina Schädel and Ted Schuur, from the Center for Ecosystem Science and Society (Ecoss), have written an article published this month inNature Geoscience.
The paper presents a new way of tracking soil carbon in permafrost, which changes the understanding of how environmental change influences ecosystem carbon storage.
The experiment is based on a long-term permafrost tundra warming study that Professor Schuur and other collaborators are doing in Alaska.
"This study was novel because we used new methods to directly track soil carbon losses, and they were much higher than we previously thought," said Professor Schuur.
"This suggests that not only is carbon being lost through greenhouse gases directly to the atmosphere, but it is also dissolving in the waters that flow through the ground and probably carry carbon into streams, leaves and rivers."
This study quantifies soil carbon relative to a fixed ash content, using the soil mineral component as a metric for pool comparisons over time, allowing the team to obtain direct measurements of changes in soil. soil carbon.
The researchers used this approach to directly measure changes in the soil carbon pool over a five-year period, showing an annual loss of more than five percent of soil carbon.
As nearly a third of the Earth's terrestrial carbon surface is trapped in permafrost, this indicates greater ramifications not only in the present, but also as the world grapples with climate change in the near future.
Scientists studying permafrost see a cycle: higher temperatures lead to further thawing of the permafrost, which leads to the release of carbon from the soil into the atmosphere, which leads to higher temperatures, which leads to the thawing of the permafrost, and so on.
According to the study, between 5 and 15 percent of the soil carbon contained in permafrost could be released into the atmosphere by the end of the century, using the current scenario.
The modeling exercise that the research team used to compare agreed with the observations, but suggests that the rate of loss could be double or higher.
"Our results demonstrate the potential for repeated measurements that quantify changes in soil carbon throughout the permafrost region to better understand its environmental fate," the study says.
"An effort like this is a critical and currently ignored link to determine the magnitude of terrestrial permafrost carbon for climate change"
Connecting all the pieces to climate change will be an important factor as global society tries to combat its effects, said Professor Schuur.
"This is critical because the carbon lost from these ecosystems ends up in the atmosphere and can accelerate climate change," he said.