As the global temperature gets progressively higher, the northernmost regions of America, Europe, and Asia have experienced an unexpected thawing. The frozen solid ground that covers much of this region, known as the permafrost, is melting due to climate change, and this is expected to have serious worldwide detrimental effects. Now researchers have found evidence that defrosting permafrost is also leaking acid.
One of the ways the melting permafrost affects its surrounding is when the solid ground melts, meltwater and many different minerals get mixed together, and then drain downhill affecting the rocks in their path. In a paper published in Geophysical Research Letters, scientists have estimated the effects of this weathering in Western Canada’s permafrost, which is more ice-and sediment-rich than others, and discovered that this permafrost meltwater contains sulfuric acid. The acid erodes rocks liberating carbon dioxide.
Thawing permafrost is already contributing to the emission of greenhouse gasses, such as methane and carbon dioxide, that were previously trapped underground. This research adds a new CO2 source, which is difficult to quantify. There is only limited work done in the chemical composition of permafrost, but it could turn out to be important. Permafrost already contains four times the carbon released into the atmosphere by humans in modern times.
However, if instead of sulfide minerals, the meltwater was rich in carbonic acid, the mineral weathering of limestone would actually consume carbon dioxide. It might not have global effects, but it might offset some of the gas released by the thawing permafrost. Currently, it is not clear just how much of the Arctic permafrost contains sulfides to start calculations.
“We can control many sources of CO2 to the atmosphere, caused by human activities, like fossil fuels and land-use change,” lead author Scott Zolkos, from the University of Alberta, told New Scientist. “But once permafrost starts to thaw and release CO2 and methane, that’s beyond our control. It’s not like we can put a giant thermal blanket on the Arctic.”
Permafrost is defined as ground that has been frozen for at least two years, but there are regions that have been frozen for millennia. Changes to those regions can have a devastating consequence for those natural habits as well as more far-reaching effects that we're only just beginning to understand.
It is not just the catastrophic release of huge amounts of greenhouse gasses, we're seeing the effects that the meltwater has on rivers, fluvial regions, and even changes to the chemistry of the ocean.
[H/T: New Scientist]