The climate change debate is getting warming due to a discovery by a team of researchers from UNC-Chapel Hill.
The team, led by Dr. Rose Cory, a UNC professor, have uncovered a new threat in the warming arctic tundra – melting of the permafrost and the subsequent release of previously frozen carbon into the atmosphere. The resulting carbon dioxide could double greenhouse gas emissions and thus have a big impact on climate change, the study found.
“What we discovered is that the conversion of previously frozen soil carbon in the Arctic to carbon dioxide (CO2, greenhouse gas) will be increased by reactions with sunlight and their effects on bacteria,” Dr. Cory, an assistant professor of environmental sciences and engineering, told WRAL News.
“This is important because tremendous stores of organic carbon have been frozen in permafrost soils for thousands of years, and if thawed and released as CO2 gas these stores have the potential to double the amount of the greenhouse gas carbon dioxide in the atmosphere on a timescale similar to human inputs of fossil fuels.”
There are physical consequences as well. Researchers found, photographed and tested areas of previously frozen tundra where gashes in the surface appeared due to the melting and resulting flow of water. Nearby waterways are turned from blue to light blue by the runoff. (A YouTube video shows some of the damage.)
While debate about melting icecaps has raged for years, the UNC team’s findings add the CO2 threat to the mix.
“Organic carbon locked into permafrost stores more than twice the amount of carbon that is currently in the atmosphere,” Cory said. “But it has always been frozen, so it has not participated in the carbon cycle for thousands of years. With the earth getting warmer, that’s all changing.”
“Thermokarst” Failures – Sinkholes and Landslides
At 27 sites, the team, which also included researchers from the University of Maryland and the University of Michigan, found what it calls “thermokarst failures,” or areas of melting. Sinkholes or landslides were produced, based on the area’s topography. The research team focused on territory in Alaksa’s far north near the Alaskan National Wildlife Reserve, or ANWR. A debate has raged for years about whether to permit oil drilling in ANWR.
They described the melting process and carbon release as “baking.” The carbon trapped in the soil is attacked by bacteria, and 40 percent or more of it is converted to CO2. Given how much CO2 is generated and how much land mass is being exposed to sunlight over time, the scientists say the impact on the environment “on a global scale,” Cory said.
The findings, which were reported in the Feb. 11 in the Proceedings of the National Academy of Sciences, could mean that more warming of the atmosphere will occur. And as more of the permafrost melts when exposed to sunlight, the more CO2 will be released.
Cory, who recently received the Camille & Henry Dreyfus Foundation award for environmental chemistry award, described the process as a “feedback” cycle.
“In other words, there is the potential for a positive feedback where as the Earth warms from human release of heat-trapping gases into the atmosphere, the frozen arctic soils also warm, thaw, and release more CO2 to the atmosphere,” she explained. “This CO2 accelerates the Earth’s warming, which further accelerates the thawing of arctic soils and the release of even more CO2.
A “Feedback” Cycle
“Our research shows that there is a greater potential for this feedback when soil carbon is exposed to sunlight at Earths’ surface.”
Cory noted that “sunlight makes carbon better food for bacteria. What that means is that if all that stored carbon is released, exposed to sunlight and consumed by bacteria, it could double the amount of this potent greenhouse gas into the environment.”
Cory warned that more CO2 means more warming. Whether one agrees or not with “global warming,” she said what’s happening in the Arctic is a”bellwether” for what is to come in the years ahead.
“There are plenty of reasons to be interested in the role of the Arctic in global climate change,” she said. “The Arctic is warming faster than the rest of the Earth, and as such is a bellwether for change. Increasing temperatures will melt ancient soils, cause damage to cold-region infrastructure, and will alter carbon cycling with resulting feedbacks at global scales. An increased understanding of the fate of carbon, and especially how and how fast it may be released to the atmosphere as CO2 where it can lead to more warming, will help define these potential impacts and thus prepare society for understanding what is to come.”
No Easy Solution
Asked if there was a way to restore areas where the thermokarst failures have occurred, she said a bigger answer was needed.
“There is no simple, “technological” fix to this problem,” Cory said. “The best remedy is to slow the rate of human inputs of greenhouse gases to the atmosphere.”
As for the threat posed by the increasing amount of CO2 itself and the entire climate change debate, Cory said change is “unavoidable,” and people need to be prepared for consequences.
“The situation of climate change requires us to think about solutions in a more integrated way, which includes understanding the science behind the change and also mobilizing government officials and managers to better prepare society for what will come,” she explained.
“In the short term we are at the mercy of the heat-trapping gases we have already dumped into the atmosphere that are causing the impacts we see today. Our best short-term strategy is to better prepare for managing the unavoidable changes that will occur, and to avoid the most drastic and unmanageable changes of the future by limiting greenhouse gas emissions now.”