Forest snows keep northern soils relatively toasty, diminishing how much climate-warming carbon they can sequester
Arctic winters may be snowy and cold, but a deep blanket of snow can actually keep the soil surface fairly warm, a new study finds — at least in taiga, the conifer forests that may constitute almost half of the Arctic’s land cover.
Temperature plays a major role in determining not only plants’ uptake of climate-warming carbon, but also the soil’s potential for storing the element.
Scientists who develop computer programs to evaluate climate under changing conditions know this. Yet for convenience, their simulations have largely treated Arctic snows as if they blanket forest-free tundra, notes climate modeler Isabelle Gouttevin of the CNRS/University Joseph Fourier-Grenoble in France.
Her team has now quantified the impact of ignoring the taiga snows’ insulating capacity in climate simulations, and found that the oversight may make a substantial difference. At a depth of 50 centimeters, soil in wintry taiga can be 12 degrees Celsius warmer than computer simulations predict when all snow-covered Arctic terrain is treated like tundra, the researchers conclude June 2 in the Journal of Geophysical Research. Gouttevin’s team also finds that because forested soils heat up from a warmer baseline in spring, their summer temperature at 50 centimeters depth could be 4 degrees Celsius warmer than all-tundra simulations had assumed.