Climate Change increases risk of releasing Toxic Mercury in Arctic Region

Permafrost, the Arctic’s frozen soil, acts as a massive ice trap that keeps carbon stuck in the ground and out of the atmosphere, where, if released as carbon dioxide, the greenhouse gas would drive global warming. But as humans warm the climate, they risk thawing that permafrost and releasing that carbon, with microbial organisms becoming more active and breaking down the ancient plant life that had previously been preserved in the frozen earth. That would further worsen global warming, further thawing the Arctic and so on.

–           That cycle would be scary enough, but U.S. government scientists on Monday revealed that the permafrost also contains large volumes of mercury, a toxic element humans have already been pumping into the air by burning coal.

–           There are 32 million gallons worth of mercury, or the equivalent of 50 Olympic swimming pools, trapped in the permafrost, the scientists wrote in a study published in the journal Geophysical Research Letters. For context, that’s “twice as much mercury as the rest of all soils, the atmosphere, and ocean combined,” they wrote.

–           Mercury, a naturally occurring element, binds with living matter across the planet – but the Arctic is special. Normally, as plants die and decay, they decompose and mercury is released back to the atmosphere. But in the Arctic, plants often do not fully decompose. Instead, their roots are frozen and then become buried by layers of soil. This suspends mercury within the plants, where it can be remobilized again if permafrost thaws.

–           The problem is that mercury, although naturally occurring, is damaging to humans and wildlife, especially in certain forms. We’re already causing buried mercury to enter the atmosphere by burning coal, which lofts the element into the atmosphere, where it travels long distances. When it rains out into the ocean or lakes, it enters the food chain, first accumulating in the bodies of microorganisms and then growing increasingly concentrated in predators that feed off smaller organisms – for instance, larger fish.

–           When humans consume mercury-laden fish in quantities too large, it can be dangerous – especially for pregnant women.

–           However, the magnitude of this risk is as yet unknown, the best option for managing these permafrost-related risks is to keep the permafrost – and the carbon and mercury contained in permafrost – frozen, through immediate reduction of fossil fuel emissions.