Berkeley Lab scientists create model to map permafrost carbon, climate feedback

Charlie Koven/Courtesy

A team of researchers, led by a scientist from Lawrence Berkeley National Laboratory, has developed a model that accounts for the atmospheric effect of emissions released from carbon sequestered in melting permafrost soil.

The computer model predicts that the thawing of Arctic permafrost soil, a consequence of global warming, will significantly contribute to greenhouse gas emissions as it releases carbon dioxide trapped inside. The team’s research was published Monday in the Philosophical Transactions of the Royal Society A journal.

Charlie Koven, a Berkeley Lab staff scientist who led the research, stressed the role of natural factors in significantly increasing greenhouse gas emissions in addition to human contribution to climate change in rain forest deforestation and car pollutants.

In recent years, according to scientists, global warming has raised temperatures to the point that the surface layers of permafrost have begun to melt, emitting some carbon dioxide into the atmosphere. The resulting emissions create a positive feedback mechanism, releasing carbon into the atmosphere that, in turn, contributes to temperature increases, causing more permafrost to melt.

As temperatures continue to rise, permafrost carbon could ultimately become a larger factor in climate change, according to Christina Schadel, a research associate at Northern Arizona University who worked on the project.

In its model of a high warming scenario, the model found that permafrost could release between 27.9 and 112.6 petagrams of carbon into the atmosphere, which Koven noted fell within the range of previous studies.

“It’s not as cataclysmic as some studies say and not as negligible as others say,” Koven said. “It’s somewhere in the middle.”

Compared with Earth system models, which consider much larger amounts of information in a global system, the research team used a simpler model, aiming to find clearer connections between the specific data entered and resulting projections.

“There’s nothing wrong with Earth system models, but we wanted to make an independent estimate using a different approach,” said Ted Schuur, a professor of ecosystem ecology at Northern Arizona University who worked on the project. “One way we check things in science is measuring them in very different ways.”

The research was funded in part by a grant from the National Science Foundation designed to increase understanding of the effects of permafrost carbon.

Schuur considers the research evidence that people should take preventative action against climate change now to prevent exponential damage to the environment in the future.

“There could be thresholds and tipping points that will make things much harder the longer that we wait,” Schuur said. “The more we can reduce our emissions now, the less we warm the planet, the less the chance there might be a big surprise coming from the Arctic in the future.”

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