Anthropogenic climate change is triggering a massive, and perhaps irreversible melting of Greenland’s ice fields.

It now appears that in addition to causing sea level rise, it appears that it is also triggering a massive release of mercury into the environment.

I had though at first that this was pollution from coal use over the past few hundred years, but this is far more extreme than would be predicted by this mechanism.  It appears that much of this mercury is natural and has been sequestered by the ice:

Greenland’s melting ice sheet is unleashing an astonishing amount of mercury into the nation’s rivers and fjords.

Downstream of three glaciers in the southwest, researchers have found coastal ecosystems are swimming in high concentrations of the heavy metal, which can build up in the food web to toxic levels.

The quantity of mercury observed in three glacial rivers and three fjords in Greenland was among the worst in recorded history. In fact, researchers say the concentrations here are only matched by the polluted waterways of Industrial China, which overall produces about one-third of the world’s mercury pollution.

As Greenland’s glaciers continue to melt in line with our worst-case scenarios, experts are worried even more trapped mercury (Hg) could one day be released into the environment.

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Previous studies have shown moderate mercury concentrations in run-off from melting glaciers, but the concentrations found in Greenland are two orders of magnitude higher than what scientists have found in other Arctic rivers.

“We didn’t expect there would be anywhere near that amount of mercury in the glacial water there,” says climate scientist Rob Spencer from Florida State University (FSU).

“Naturally, we have hypotheses as to what is leading to these high mercury concentrations, but these findings have raised a whole host of questions that we don’t have the answers to yet.”

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If the hunch is right, Greenland may very well be a neglected hotspot of natural mercury emissions, which have been trapped in ice for millennia. Even if we curb industrial mercury emissions tomorrow, the rapid melting of all this ice could sabotage human efforts to reduce pollution from this heavy metal to safe levels.

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“But mercury coming from climatically sensitive environments like glaciers could be a source that is much more difficult to manage.”

Given that Greenland is a major exporter of seafood, and the region is home to precious marine ecosystems, we’d best find out what’s going on.

The study was published in Nature Geoscience.

The fact that this may be a natural source is potentially even more concerning, because it can be far more extreme and unpredictable.

We are in for a bumpy ride.