Alarm bells are ringing with a new study claiming that if the current rate of permafrost thawing continues, it could unleash massive amounts of carbon in the atmosphere within just a few decades.
Permafrost is soil that has remained frozen for years or centuries under topsoil. Permafrost are said to be one of the richest sources of carbon because of carbon-rich organic material, such as leaves, that froze without decaying. As rising Arctic air temperatures cause permafrost to thaw, the organic material decomposes and releases its carbon to the atmosphere in the form of the greenhouse gases carbon dioxide and methane.
For their predictions, researchers used data on soil temperatures in Alaska and Siberia from the University of Alaska, Fairbanks, with a numerical model from the National Center for Atmospheric Research in Boulder, Colorado, to calculate the changes in carbon emissions as plants grow and permafrost thaws in response to climate change.
Researchers divided the Arctic into two regions of equal size, a colder northern region and a warmer, more southerly belt encircling the northern region and assessed when the Arctic will transition to a carbon source instead of the carbon-neutral area it is today — with some processes removing about as much carbon from the atmosphere as other processes emit.
There is far more permafrost in the northern region than in the southern one. Over the course of the model simulations, northern permafrost lost about five times more carbon per century than southern permafrost.
The southern region transitioned more slowly in the model simulations, Parazoo said, because plant growth increased much faster than expected in the south. Plants remove carbon dioxide from the air during photosynthesis, so increased plant growth means less carbon in the atmosphere. According to the model, as the southern Arctic grows warmer, increased photosynthesis will balance increased permafrost emissions until the late 2100s.