Picture 500 million cars stacked in rows. That’s how much carbon—about 1,000 petagrams, or one billion metric tons—is locked away in Arctic permafrost.
Currently, scientists estimate that 5-15% of the carbon stored in surface permafrost soils could be emitted as the greenhouse gas carbon dioxide by 2100, given the current trajectory of global warming. This emission, spurred by microbial action, could lead to 0.3 to 0.4 degrees Celsius of additional global warming.
But this estimation is missing a crucial path that carbon dioxide may be entering the atmosphere: sunlight.
According to a University of Michigan study, organic carbon in thawing permafrost soils flushed into lakes and rivers can be converted to carbon dioxide by sunlight, a process known as photomineralization.
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