About 50 percent of the world’s organic carbon stored in the soil is locked down in the frigid northern reaches of the Arctic, below an icy permafrost cap and in rich peat lands. If all that carbon were released, atmospheric CO2 concentrations could go up a whopping 660-870 parts per million.
Global warming is gradually unlocking these Arctic carbon reserves. In a paper published recently in the Journal of Geophysical Research, University of Alaska, Fairbanks geophysicist Guido Grosse and colleagues tease out two forces acting on the Arctic carbon reserve. “Press” disturbances present a slow, persistent force on the carbon reserves. And “pulse” disturbances present rapid and extreme releases. The result is a complicated web of environmental implications for the Arctic and the globe.
At Point Hope, Alaska, the tundra is gradually succombing to the effects of warming. Photo: Josh Kellogg.
Among the most important “press” disturbances is the continual melt of Arctic permafrost, which until now has kept deep layers of carbon-rich soil intact. By the year 2100, an estimated 20 percent of all the permafrost will be seasonal only, which has dramatic ramifications on the soil ecology. Warming soils will change the biological processes (enzyme kinetics) of plant ...