Assessing some risks of thawing permafrost

A team of scientists led by the U.S. Geological Survey, or USGS, has found that the thawing of permafrost could release as much as 44 billion tons of nitrogen and 850 billion tons of carbon into the environment, according to a news release issued by the USGS. Permafrost, or supposedly permanently frozen ground, is pervasive across the Arctic and is under threat of melting, as the Earth’s climate warms.

“This study quantifies the impact on Earth’s two most important chemical cycles, carbon and nitrogen, from thawing of permafrost under future climate warming scenarios,” said USGS Director Marcia McNutt. “While the permafrost of the polar latitudes may seem distant and disconnected from the daily activities of most of us, its potential to alter the planet’s habitability when destabilized is very real.”

“The scientific community researching this phenomenon has made these international data available for the upcoming Intergovernmental Panel on Climate Change,” said study lead Jennifer Harden, USGS research soil scientist. “As permafrost receives more attention, we are sharing our data and our insights to guide those models as they portray how the land, atmosphere, and ocean interact.”

The scientists conducting the study obtained the carbon and nitrogen release estimates by investigating how different types of permafrost-affected soils thaw in response to various climate scenarios. The scientists discovered that soil material with a high peat content will tend to release nitrogen into both the atmosphere and the ecosystem. More nutrient-rich soils, on the other hand, will tend to move nitrogen just into the ecosystem. All soil types will release carbon dioxide, and possibly methane.

A major release of carbon and nitrogen could exacerbate global warming and would impact water systems, USGS says. The study results have been published in the journal “Geophysical Research Letters.”

—Alan Bailey