Melting Arctic Permafrost Could Unleash Earth's Largest Reserve of Mercury
Mercury is a visually fascinating, but poisonous, element. The children of yesteryear would often celebrate when a thermometer broke, the metallic liquid leaked out, and they would play with it as a sort of proto-silly putty. Then a ton of them started getting very sick and dying.
Now, a new study about how much mercury found that that the largest reserve of natural mercury is trapped in the Alaskan permafrost. What's more, the rising air temperatures caused by climate change risks melting that permafrost layer, thus releasing large quantities of mercury into ecosystems around the globe.
"Our results indicate the active layer alone represents the largest [mercury] reservoir on the planet," says the study, published yesterday in the Geophysical Research Letters journal. "The active layer and permafrost together contain nearly twice as much [mercury] as all other soils, the ocean, and the atmosphere combined."
This amounted to about 15 million gallons of mercury in the northern permafrost—approximately 10 times more than all of manmade mercury emissions over the last 30 years. This could have huge consequences for the environment.
"There would be no environmental problem if everything remained frozen, but we know the Earth is getting warmer," said lead study author Paul Schuster. "Although measurement of the rate of permafrost thaw was not part of this study, the thawing permafrost provides a potential for mercury to be release—that's just physics."
Steve Sebestyen, a research hydrologist at the USDA Forest Service in Grand Rapids, Minnesota, who wasn't involved with the study, nonetheless acknowledges that it sets in motion a potentially catastrophic chain of events: if the mercury is transported across waterways, it risks becoming absorbed by microorganisms and transformed into methylmercury, a toxin that causes illness and disease in animals ranging from motor impairment to birth defects.
"There's a significant social and human health aspect to this study," he said. "The consequences of this mercury being released into the environment are potentially huge because mercury has health effects on organisms and can travel up the food chain, adversely affecting native and other communities."
Though some of the worst-case climate change scenarios have recently been debunked, a recent study of climate change's effects on Norweigan Glaciers revealed some 6,000-year-old, pre-Viking artifacts preserved in melted ice that helped form a picture of the region's climate history. Meanwhile, climate change is causing 99 percent of Australian sea turtles to be born female, and will also likely contribute to an increase in volcanic eruptions in the coming years.