MERCURY IN ARCTIC’S PERMOFROST (Syllabus: GS Paper 3 – Env and Eco)

Context: A recent study warns that the thawing of Arctic permafrost due to climate change is releasing vast amounts of toxic mercury into the environment, posing severe health risks to global flora and fauna.

Permafrost

• Definition: It refers to ground that stays consistently frozen—reaching temperatures of 32°F (0°C) or below—for a minimum of two consecutive years. Such permanently frozen areas are prevalent in locations with elevated mountains and in the higher latitudes of the Earth, particularly near the North and South Poles.
• Geographical Distribution: Arctic regions of Siberia, Canada, Greenland, and Alaska—where nearly 85 percent of the state sits atop a layer of permafrost.

o Also found on the Tibetan plateau, in high-altitude regions like the Rocky Mountains.

• Composition: Permafrost comprises a blend of soil, rocks, and sand that are bound together by ice. Throughout the entire year, both the soil and ice within permafrost remain in a frozen state.
• Organic Carbon: Near the surface, permafrost soils house substantial amounts of organic carbon, a residue from deceased plants that failed to decompose due to the persistent cold. Deeper permafrost layers, in contrast, predominantly consist of mineral-rich soils.

Arctic Mercury Contamination

• Global Contaminant: Mercury, a significant global environmental contaminant, originates from both natural sources and human activities.

o Mercury is a neurotoxin that can severely damage the brain and nervous system, particularly through bioaccumulation in the food chain.

• High Mercury Concentrations: The amount of mercury stored in Arctic permafrost surpasses the total mercury present in all other earth systems combined, including oceans, soils, atmosphere, and biosphere.
• Transport to the Arctic: The majority of mercury in the Arctic is transported from outside the region through long-range air and ocean pathways, with over 98% of atmospheric mercury being emitted elsewhere.
• Impact on Arctic Populations: Arctic residents, including indigenous communities, are among the most exposed populations globally, facing heightened health risks due to mercury contamination.
• Permafrost Accumulation: Mercury absorbed by plants in the Arctic eventually becomes part of the soil and freezes into permafrost, accumulating over thousands of years.
• Climate Change Effects: The thawing of permafrost, accelerated by climate change, releases stored mercury, posing increased risks as this ‘giant mercury bomb’ becomes more likely to impact the environment