Study shows arctic ecosystem shifting from carbon sink to carbon source

2016-02-22-alaskaA new study measuring carbon dioxide emissions from frozen soils finds that carbon loss from soils during the snow covered period offsets carbon uptake by plants during the growing season. This results in a shift in the subarctic tundra ecosystem from a carbon sink to a carbon source, meaning that these ecosystems are now contributing to climate change.

Furthering their research on permafrost thaw, a team of scientists conducted a study in the Alaskan tundra and produced its results in an article recently published in the Journal of Geophysical Research: Biogeosciences. The authors, including WHRC’s Associate Scientist Susan Natali, found that as the high latitudes continue to warm, particularly during winter, the vast reservoirs of permafrost carbon are indeed becoming more vulnerable.

The study, which focused in the high latitudes and on the arctic winter, the region and season where the greatest warming is occurring, was conducted at a climate change experiment near Denali National Park and Preserve over the period 2008 – 2014. Stored over millennia in the Earth’s high latitudes, permafrost – or frozen soil – contains twice as much carbon as is currently in the atmosphere. As that region warms, permafrost will become vulnerable to a heightened rate of decomposition, resulting in a potentially enormous release of carbon dioxide to the atmosphere.

According to Dr. Natali, “Carbon losses during the winter were even higher in areas where the soil was experimentally warmed, suggesting that continued warming in the Arctic will lead to greater carbon emissions to the atmosphere, further exacerbating climate change.”

This study highlights the importance of winter respiration to annual carbon budgets in the Arctic, but, adds Dr. Natali, “further work is needed to determine regional estimates of carbon emissions from the Arctic during the non-growing season.”

Link to abstract » Increased wintertime CO2 loss as a result of sustained tundra warming

WHRC is an independent research institute where scientists investigate the causes and effects of climate change to identify and implement opportunities for conservation, restoration and economic development around the world.