Study: High Levels of CO2 Could Boost Biomass Carbon Absorption in Parts of Alaska 'til 2100

Jul 1, 2016

A possible short-term benefit to a greenhouse gas …


Scientists have long worried the warming climate caused by buildup of carbon in the atmosphere will thaw long-frozen Arctic soils, which in turn will release more carbon. As will wildfires, which new research says will become more commonplace in Alaska.

“What we’ve found is, for the boreal forest, we can expect to see more frequent and larger-extent fires, like we’ve been seeing in the past two decades,” says Scott Rupp, a UAF forestry professor.

UAF forestry professor Scott Rupp explains moisture content in boreal forest "duff" – vegetation and organic matter on the forest floor – and its effect on fire behavior during a 2009 outing to the Nenana Ridge Research Burn near Fairbanks.
Credit UAF

Rupp contributed to a recently published U.S. Geological Survey assessment of recent research on the dynamics of carbon in Alaskan ecosystems. The study raised eyebrows because it suggests among other things that higher levels of atmospheric carbon will boost vegetation growth in northern and southeastern Alaska enough to offset the carbon released from the state’s boreal forests through thawing and wildfires.

“For the boreal forest, we do see a loss of carbon for that portion of the system,” Rupp said. “It’s just being offset by some of the other portions of the Alaska.”

David McGuire, co-principal investigator for the assessment, says researchers weren’t expecting that finding.

David McGuire, right, an ecosystem modeler for UAF and USGS, and a volunteer conduct field research in 2012 in the Kanuti National Wildlife Refuge northwest of Fairbanks.
Credit UAF

“It’s surprised us a little bit, in that we thought that drought would play a stronger role and that permafrost thaw might expose more carbon than it did in the soil to decomposition,” he said.

McGuire is an ecosystem modeler for UAF and the USGS, and he co-wrote and co-edited the assessment, which he says focuses only on Alaska, but is consistent with other findings elsewhere around the Arctic.

“In Russia, they indicate that they have large carbon uptake at this time. And they also have large wildfires,” he said.

The assessment says although Alaska encompasses less than a fifth of U.S. territory, it holds more than half the country’s total stored carbon.

The USGS assessment suggests among other things that high levels of atmospheric carbon could boost vegetative growth in northern, western and southern Alaska sufficiently to offset carbon production in the boreal forests of the Interior and southcentral portions of the state, through the year 2100.
Credit USGS

It also says around the year 2100, Alaska’s boreal forests will be producing more carbon than vegetation in the other regions will be able to absorb. So, McGuire says, the study shouldn’t be interpreted as proof that climate scientists’ concerns over atmospheric-carbon buildup are overblown.

“While on the surface, it may look like it’s good news for climate skeptics … a lot of carbon could come out after 2100,” he said.

McGuire says more research is needed on the impact of carbon on the Arctic climate, as well as other climate-change agents such as methane.

Editor's note: This story was edited for online publication.