The summer season above the arctic circle may be brief, but due to rising average temperatures the permanently frozen ground is beginning to thaw. Underlying the tree-less sub-arctic tundra is a thick layer of partly decayed plant material, laid down over the eons, which contains a massive amount of carbon and methane gas.
The gradual melt-down of that organic layer is releasing its stored carbon in the form of carbon dioxide, which would aggravate the greenhouse pollution that is already at critical levels high up in our atmosphere.
The ominous break-down of the permafrost is being studied by the Woods Hole Research Center, an independent climate change think-tank headquartered in Massachusetts. Senior scientist Max Holmes said that the fate of permafrost has all kinds of consequences for people and animals living in arctic regions as well as globally. The scale of the thawing is immense and circumpolar, across Alaska, northern Canada, Europe, and Siberia.
Student teams from the University of Alaska have been drilling sample cores in the frozen tundra and discovered that the permafrost extends down to 500 metres in some regions, but 20 metres below the surface the ground temperature had already risen by 3 degrees C over the past decades.
The effect of the thaw is that the banks of northern rivers are collapsing, sending carbon-rich silt downstream choking off all life. Parts of the tundra are slumping, creating extensive depressions that fill with water, rendering the tundra region less suitable as habitat for terrestrial wildlife including caribou.
The melting of permafrost directly impacts northern residents because the foundations of buildings are shifting, walls are cracking, roads and airport runways are buckling. A less obvious but very serious environmental factor with global implications is that the melting of frozen organic matter also releases methane gas, which is twenty to twenty-five times more potent as a greenhouse gas than CO2.
“Methane is made up of one atom of carbon and four hydrogen atoms,’ says Dr. Kevin Schaefer, a polar research scientist with the National Snow and Ice Data Center at the University of Colorado. Methane smells of rotting eggs and is commonly known as swamp gas, a volatile and combustible gas that bubbles up from marshy ponds and wetlands in spring. Methane is released by microbes and bacteria eating the organic bottom sediments of water bodies. In combination with oxygen, the gas turns into carbon dioxide (CO2), but in the absence of oxygen, the end product is methane, which is the most likely scenario in the arctic tundra because much of the formerly frozen ground is saturated with water.